EP2318325A2 - Formulation d'oxyde de métal valve - Google Patents

Formulation d'oxyde de métal valve

Info

Publication number
EP2318325A2
EP2318325A2 EP09781550A EP09781550A EP2318325A2 EP 2318325 A2 EP2318325 A2 EP 2318325A2 EP 09781550 A EP09781550 A EP 09781550A EP 09781550 A EP09781550 A EP 09781550A EP 2318325 A2 EP2318325 A2 EP 2318325A2
Authority
EP
European Patent Office
Prior art keywords
dispersion
acid
carboxylic acid
short
suspension
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09781550A
Other languages
German (de)
English (en)
Inventor
Benno Gries
Jörg LAUBE
Rolf Wagner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HC Starck GmbH
Original Assignee
HC Starck GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by HC Starck GmbH filed Critical HC Starck GmbH
Publication of EP2318325A2 publication Critical patent/EP2318325A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
    • C04B35/486—Fine ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/62685—Treating the starting powders individually or as mixtures characterised by the order of addition of constituents or additives
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63416—Polyvinylalcohols [PVA]; Polyvinylacetates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63424—Polyacrylates; Polymethacrylates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63444—Nitrogen-containing polymers, e.g. polyacrylamides, polyacrylonitriles, polyvinylpyrrolidone [PVP], polyethylenimine [PEI]
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63448—Polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63468—Polyamides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3225—Yttrium oxide or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
    • C04B2235/449—Organic acids, e.g. EDTA, citrate, acetate, oxalate
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5409—Particle size related information expressed by specific surface values
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/604—Pressing at temperatures other than sintering temperatures
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/608—Green bodies or pre-forms with well-defined density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/61—Mechanical properties, e.g. fracture toughness, hardness, Young's modulus or strength
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/76—Crystal structural characteristics, e.g. symmetry
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/77—Density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance

Definitions

  • Zirconia is used as a so-called partially or fully stabilized zirconium oxide for the production of ceramic bodies, which are used as components. Examples include medical implants, thermal barrier coatings, pump rotors or mill linings, but also highly stressed and filigree design components. These components are usually produced by various methods of shaping and subsequent sintering at temperatures above 1000 0 C from a ceramic powder.
  • the shaping of the zirconium oxide powder can be carried out by various methods familiar to the person skilled in the art, such as injection and strip casting, extrusion, slip casting or electrophoretic deposition, but also more easily and inexpensively by axial pressing at or in the vicinity of the room temperature (“cold pressing” in contrast) for hot pressing, where axial compression takes place at high temperatures.)
  • a special form of cold pressing is isostatic pressing, wherein the powder is introduced into a flexible container, this sealed and compacted by means of a liquid as a pressure transmitter at pressures between 300 and 2200 bar. This shape is particularly used for large components, in which case the press or sintered body is machined to work out the contour of the component.
  • the pressed parts are sintered over a suitable temperature control over time, whereby the usual contents of organic aids are decomposed and expelled in the form of gases.
  • the aids have a variety of tasks, among others, they act as a lubricant to allow the necessary in the pressing compression plastic displacement of the per se brittle-hard ceramic particles past each other.
  • Other organic aids act as
  • Examples of pressing or sliding aids are paraffin, ester or acid amide waxes
  • examples of binders are polyethylene glycols, polyvinyl alcohols or polyacrylates whose functional group may also be esterified or alkylated
  • a liquid plasticizer is used, for example glycol, glycerol or a low molecular weight polyethylene glycol, in order to make the binding agent plastically deformable. This enumeration is not exhaustive.
  • Inorganic powders with organic auxiliaries are formulations.
  • Zirconia powders having specific surface areas high enough to provide sufficient driving force for pressureless sintering serve as the starting material for isostatic or axial pressing. Common values are between 3 and 50 m2 / g.
  • stabilization in connection with zirconium oxide is meant that in the lattice of the zirconium oxide other metal oxides are dissolved, which as pure oxides another metal:
  • Oxygen ratio have as ZrO2. Usual are Y2O3, MgO, CaO and other oxides from the group of rare earth oxides, as well as combinations of two or more of the aforementioned oxides. Partial stabilization causes a shift in the transition temperature from tetragonal to monoclinic. Since phase transformations of ZrO 2 are associated with volume changes that would lead to the destruction of the ceramic body, industrially manufactured
  • Ceramic body mainly made of partially or fully stabilized zirconia whose conversion is frozen to the monoclinic lattice type at room temperature.
  • other oxides may also be included which form crystalline or glassy foreign phases, e.g. A12O3, or silicates.
  • a partially or fully stabilized zirconia powder for the production of ceramic bodies should have the lowest possible monoclinic phase content, since it is feared that a high monoclinic phase content is an indication of a poor distribution of the Stabilizing oxide in the zirconia lattice, which leads to diffusion transport during sintering and also to tensions, which in turn reduces the strength of the sintered.
  • the strength is usually determined by bending fracture test on sintered and ground bars according to ISO 843 (4-point bending strength) or JIS R 1601 (3-point bending strength). This doctrine has led to the fact that the production process of partially stabilized zirconia powder to point out to have the lowest possible monoclinic phase content.
  • the formulation is carried out with organic auxiliaries. If cold isostatic or axial pressing is intended as intended use and the powder is thus dry required for the indirect shaping, the zirconium oxide powder is usually dispersed in a liquid, the required auxiliaries dissolved or dispersed therein, optionally the suspension is then subjected to milling by means of a crushing unit, and then dried by sputtering or fluidized bed drying to form a formulation. This produces agglomerates in the range of 50 to 1000 microns dimension.
  • Agglomeration is not absolutely necessary for cold isotstatic pressing, where the formulation can also be prepared so that the zirconium oxide is wetted with a liquid which contains or disperses the required auxiliaries, and the moist powder is dried in a tumble or paddle dryer, for example becomes.
  • the organic aids remain largely after drying, unless unwanted evaporation losses occur.
  • Formulated zirconia powders often still contain organic adjuvants which facilitate the preparation of the dispersion, e.g. Condensers, defoamers, surfactants or reagents for pH adjustment.
  • the liquid used to prepare the dispersion can be either water, alcohols, hydrocarbons, or a ketone or mixtures thereof.
  • organic liquids are an industry standard, it has some disadvantages. These include, for example, flammability, explosiveness of vapors when mixed with air, and adverse health effects on exposed workers.
  • Water is also considered as a liquid, but difficulties arise here because the granules obtained are very hard due to strong interactions of the powder particles with each other (this phenomenon is used, for example, in the production of pottery, where it is the broken body after drying - A -
  • powder formulations for ceramics of zirconium oxides are hitherto preferably prepared from organic liquids as a dispersing liquid by drying.
  • the bending strength of sintered ceramic bodies which is an essential quality criterion, depends on several factors. The most important influencing factors are microstructural defects, as shown by pores or inclusions. Thus, high sintered density and absence of foreign phases, inclusions and macropores are necessary prerequisites. However, a high sintering density is only achieved if the driving force of the sintering is high enough. This is achieved by the specific surface area of the zirconium oxide powder or by its optically determinable primary particle size. Another is a high density. Furthermore, an isotropic pressure density after pressing is necessary, because pressing errors or areas with low compactness produce macropores, sintering distortion or
  • Tensions in the ceramic body A strength of at least 800 MPa, better still greater than 900 MP according to ISO 843 is to be strived for, so that a universal usability of the components is given.
  • the hitherto known zirconium oxide powders as formulations with organic auxiliaries can indeed be produced to give sintered bodies having sufficient strength, but not in net shape technology by means of axial pressing.
  • a large proportion of hard machining is nowadays inevitably required, which has to be carried out consuming with expensive diamond or cBN tools.
  • green state processing may be performed, but this requires green strength and results in powder losses that are difficult to recycle.
  • organic auxiliaries zirconia which can be processed without sacrificing the properties of the sintered body by means of axial compression in net shape technology with little waste to sintered parts without excessive hard machining. Therefore, a sufficiently high cohesiveness is required. This depends almost entirely on the organic aids used, since the ceramic particles, in contrast to metal powders, to behave neither ductile nor kaltversch spabar when compacting and the cohesiveness must be prepared entirely by the organic auxiliaries.
  • Compact density is a measure of the deformation resistance and should be possible low, preferably less than 200 MPa at 50% of the theoretical density
  • the coefficient of friction (a measure of the friction of the powder on the wall of the pressing tool during the compression process, the value should be as close as possible to one, otherwise wear of the dies occurs),
  • the cohesiveness (a measure of the inner cohesion of the compact when ejected from the mold, the value).
  • the cohesiveness is calculated from the ratio of the green strength and the required ejection force, therefore the value should be at least close to one, but at least above 0.8. Otherwise, damage to the compact during ejection is to be expected
  • the actual green density measured at the ejected pressing may be less than the predetermined green density due to the back elongation.
  • Another measure of compressibility is the so-called Hausner Ratio, which is the ratio between tapping and bulk density. The larger the Hausner ratio is beyond the value of one, the lower the resistance to deformation of a powder.
  • Another measure of compressibility is the pressing pressure necessary to achieve a specific press density. This is important for industrial applications because it determines the necessary pressing force in large parts. If the compact density is too low, because, for example, not enough strong press in axial pressing is available, so no sufficient sintering density is achieved. Since then remain pores, the strength of the ceramic part is weakened.
  • Zirconia powder with organic additives wherein the pressing pressure necessary to achieve a green density of at least 50% of the theoretical density is 200 MPa or less and the cohesiveness is 0.7 or more.
  • the invention also relates to an agglomerated zirconium oxide formulation with organic auxiliaries, which can be compressed at pressures of 200 MPa or less to pressures of at least 50% of the theoretical density and a force required to destroy the compact in the axial and radial directions 10 MPa or more and a has sufficient strength in the sintered part.
  • the zirconia in the formulation is stabilized with 2 mole% to 12 mole% yttria, preferably 3 mole% to 8 mole% or 3 mole% to 6 mole%.
  • the zirconium oxide has a monoclinic phase fraction of up to 30%, preferably up to 40%, in particular up to 50% or more.
  • Phase content is however at most 90%.
  • the pressing pressure at which 50% of the theoretical density is reached is less than 200 MPa, preferably less than 150 MPa, advantageously less than 100 MPa, particularly advantageously less than 90 MPa, in particular less than 80 MPa. Most advantageously, this value is less than 70 MPa.
  • the cohesiveness is greater than or equal to 0.7, advantageously greater than 0.8, in particular 1 or greater.
  • the formulation according to the invention contains organic auxiliaries.
  • the formulation advantageously contains at least one carboxylic acid.
  • This carboxylic acid is in amounts of 0.1 to 5 wt .-%, advantageously in amounts of 0.25 to 2.4 wt .-%, in particular 0.5 to 1 wt .-%. In general, use of 0.5% by weight or more of the carboxylic acid gives good results.
  • the carboxylic acid advantageously has a melting point of 35 ° C to 100 0 C.
  • the invention also relates to a process for preparing a zirconium oxide formulation, wherein the zirconium oxide in the presence of a solvent at least one carboxylic acid and at least one
  • Binder is added.
  • the zirconium oxide is present as a dispersion or suspension in the solvent.
  • this is done with water as a solvent in the preparation of the suspension or
  • Dispersion as an intermediate into which the carboxylic acid and the binder are introduced.
  • the carboxylic acid and the binder may be used together, i. may be added together in a solvent, dispersed or suspended, added, or spatially separated from one another but added simultaneously, but advantageously sequentially, to the suspension or dispersion of the zirconia.
  • the carboxylic acid can also be added in solid form or in the form of a melt.
  • the invention thus also relates to a process for the preparation of a zirconium oxide formulation with the
  • the addition of the carboxylic acid takes place at a basic pH and is preferably carried out at a pH of 8 to 12, preferably from 8.4 to 11, in particular at a pH of 9 to 10.
  • the addition of the binder is also carried out at a basic pH, preferably at a pH of 8 to 12, preferably from 8.4 to 11, in particular at a pH of 9 to 10.
  • the addition of both the binder and the carboxylic acid takes place at a temperature of less than 60 0 C, advantageously less than 50 0 C, in particular less than 35 ° C.
  • the temperature is ideally at room temperature, ie from about 15 ° C to about 28 ° C, especially at 18 ° C to 23 ° C.
  • the drying can be carried out in principle by any known method, preferred are spray-drying or related methods.
  • the carboxylic acids used remain advantageous in the final product, the granules.
  • Zirconia formulation comprising the steps of: providing a zirconia suspension or dispersion;
  • Carboxylic acids are understood as meaning those organic substances which have at least one or more carboxyl groups or which are obtained by reaction in the suspension. At least one carboxyl group is not esterified according to the invention, but is present in protonated form.
  • the carboxylic acid can also be used as salt, with water-soluble salts of the alkali or alkaline earth metals, zirconium, yttrium or ammonium salts being advantageous. It is also possible to use corresponding acid chlorides, since they are available in aqueous media Carboxylic acids hydrolyze, which is why they are also referred to as carboxylic acids in the context of the invention.
  • the formulation according to the invention particularly preferably contains those carboxylic acids which are in their solid form at room temperature, since they have a low vapor pressure and thus ensure their retention in the dried formulation.
  • Room temperature liquid carboxylic acid can be used, e.g. Acetic acid or its salts, if necessary for reasons of pH control.
  • carboxylic acid salts are advantageous, since in this case the volatility is reduced.
  • a carboxylic acid of waxy consistency is used, the melting point or melting range between 35 and 100 0 C.
  • the carboxylic acid may also contain ether and / or hydroxyl groups.
  • at least one carboxyl group is terminal.
  • the carboxylic acid may also be short-chain and still be solid at room temperature, but has a higher acidity, for example, oxalic, tartaric or citric acid.
  • carboxylic acids it is generally possible to use monodi-tri- or polycarboxylic acids which have 1 to 30 carbon atoms and advantageously a melting point or
  • short-chain carboxylic acids can be used, which according to the invention are understood as meaning carboxylic acids having 1 to 8 carbon atoms. These advantageously have a melting point or melting range of from 35 to 100 ° C. and are present either as free carboxylic acid or as alkali metal or ammonium salt.
  • carboxylic acids having 10 to 30 carbon atoms, in particular 10 to 23 carbon atoms.
  • aliphatic carboxylic acids which may be saturated or unsaturated.
  • the carbon chain can be linear, branched or ring-shaped, with linear or branched aliphatic carboxylic acids being advantageous.
  • the carbon chain may also contain ether groups.
  • the carboxylic acids may be unsubstituted or substituted, wherein as substituents one or more nitro groups, amino groups, F, Cl, Br, I, or hydroxyl groups are advantageous or also contain ether or hydroxyl groups, such as hydroxypropionic acid or citric acid.
  • the carboxylic acids may also be monounsaturated or polyunsaturated
  • the langekettigenKarbon Acid saturated fatty acids with a melt point or pain area between 35 and 100 0 C such as montanic acid, palmitic acid, stearic acid, mixtures thereof with each other or other carboxylic acids or mixtures of alkali metal or ammonium salts with each other or other carboxylic acids or their Alkahmetall- are advantageous or ammonium salts.
  • formic acid acetic acid, oxalic acid, glycolic acid, propionic acid, methoxyacetic acid, lactic acid, malonic acid, butyric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, butanedioic acid, ethoxyacetic acid, 2,2'-oxydiacetic acid, methoxypropionic acid, succinic acid, ascorbic acid
  • Methylglutaric acid citric acid, 2,3,4,5-tetrahydroxyhexanoic acid (mucic acid), onanethic acid, 2-propylpentanoic acid, butylmalonic acid, diethylmalonic acid, tetrahydroxyheptanoic acid (quinic acid), 2- [2- (methoxyethoxy) ethoxy] acetic acid, azelaic acid, (3R, 4S , 5R) -3,4,5-T ⁇ hyd ⁇ oxy- 1-cyclohexencarboxylic acid (shikimic acid), caprylic acid, pelargonic acid, nonanedioic acid (azelaic acid), sebacic acid, the salts of which are used with alkali metal or ammonium salts, acid chlorides or mixtures thereof
  • carboxylic acids ie carboxylic acids having 10 to 30 carbon atoms
  • fatty acids, their alkali metal or ammonium salts can generally be used. It is more preferably solid at room temperature. It is possible to use saturated as well as mono- or polyunsaturated fatty acids.
  • Suitable and widespread suitable long-chain carboxylic acids according to the invention are saturated fatty acids such as lauric, myristic, palmitic, Marga ⁇ n 1972re, stearic, arachidic, behenic, lignoceric, cerotic, montanic, mehssinklare, monounsaturated fatty acids such as undecylenic, myristoleic, palmitoleic, petroselinic, oleic, elaidic , Vaccenic acid, gadoleic acid, icosenoic acid, cetoleic acid, erucic acid,
  • saturated fatty acids such as lauric, myristic, palmitic, Marga ⁇ nklare, stearic, arachidic, behenic, lignoceric, cerotic, montanic, mehssinklare, monounsaturated fatty acids such as undecylenic, myristoleic, palmitoleic, petroselinic, oleic,
  • Nervonic acid polyunsaturated fatty acids as well as linoleic acid, alpha-linolenic acid, gamma-linolenic acid, calendic acid, punicic acid, alpha-eleostearic acid, arachidonic acid, timnodonic acid, clupanodonic acid, cervonic acid, vernolic acid, ricinoleic acid and mixtures thereof and mixtures of their alkali metal and ammonium salts.
  • the carboxylic acid is preferably added as an aqueous dispersion, and in this case may also contain emulsifiers, such as fatty acid glycine esters If it is partially or completely neutralized, for example with ammonia, also at least partially as a solution.
  • emulsifiers such as fatty acid glycine esters If it is partially or completely neutralized, for example with ammonia, also at least partially as a solution.
  • the carboxylic acid may also be a mixture of several different carboxylic acids, in this case one speaks of a carboxylic acid preparation.
  • a solution or a dispersion of one or more carboxylic acids, both optionally also partially neutralized by ammonia or short-chain amines, is called carboxylic acid preparation. It may also be a mixture of a solution and a dispersion.
  • At least one short-chain and one long-chain carboxylic acid are used, which can advantageously be used as the carboxylic acid formulation as a solution, dispersion or partially dissolved and dispersed as described above.
  • the long-chain and short-chain carboxylic acids may be added as a formulation together, simultaneously or sequentially. Since a simpler reactor can be used for this purpose, the sequential addition is advantageous, in which case the short-chain carboxylic acid is advantageously added first.
  • Table 1 shows suitable combinations of short-chain carboxylic acids with long-chain carboxylic acids or their preparations. Individual combinations are designated by the number of the table followed by the number of the respective combination in Table 1.
  • combination 2.005 means the combination of the carboxylic acids as in Table 1, Item No. 5 with the form shown in Table 2, in which Carboxylic acid is present.
  • Table 2 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt. For carboxylic acids with multiple acid functions, all acid functions are present as salt.
  • Table 3 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the potassium salt. For carboxylic acids with multiple acid functions, all acid fusions are present as salt.
  • Table 4 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the zirconium salt. For carboxylic acids with multiple acid functions, all acid fusions are present as salt.
  • Table 5 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the ammonium salt. For carboxylic acids with multiple acid functions, all acid fusions are present as salt.
  • Table 6 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt. For carboxylic acids with several acid functions, all acid functions are present as salt.
  • acids or their salts can be used both for pH adjustment and, especially in partially or completely neutralized form, e.g. with ammonia or water-soluble amines, for pH buffering, which can improve the control of viscosity and stability of the dispersion.
  • the carboxylic acid preparation is added to the suspension prior to drying.
  • the addition of the carboxylic acid preparation can also take place at any time during the milling step, in this case particularly preferably towards the middle or end of the milling step. It is also possible to add the various proportions of the carboxylic acid preparation at different times. Very particularly preferred is the addition before drying, wherein the suspension of zirconium oxide is stirred or sheared or otherwise mixed in itself and with the carboxylic acid preparation.
  • the state of the carboxylic acids before and after drying and their mode of action can not be precisely defined.
  • any short-chain carboxylic acids present are dissolved in the water or adsorbed on the surface of the ceramic particles, with the acidic carboxyl group binding to the alkaline surface of the zirconia particle. If the short-chain carboxylic acid is partially neutralized, ammonium ions would be released, which raise the pH of the solution, which can also be observed in practice (eg in Example 2).
  • the long-chain carboxylic acid could form micelles in the center of which one or more zirconia particles could be located.
  • the carboxyl group of the long-chain carboxylic acid could be located on the surface of the micelle, while the alkyl radical points inwards and enters into a weak interaction with the enclosed ceramic particle, which may be covered by an adsorbate layer.
  • the ceramic particles become hydrophobic and can no longer form incrustations on drying, which would explain the effect of good plastic deformability of the granules of Examples 2 and 3.
  • Accurate studies on the mechanism of action are very difficult and require expensive methods, since the concentration of carboxyl group is too low for a study with the known methods.
  • Polyelectrolytes such as polyacrylic acid or its salts are not carboxylic acids in the sense of this invention, but can be used as binders within the meaning of the invention.
  • the formulation of the invention also contains a binder which ensures the stability of the compact.
  • Polymers in particular polymers are preferred which have a ceiling temperature of 220 0 C or less, preferably 200 0 C or less, for example, polyethers such as polyethylene glycols (preferably of molecular weights of 1000 to 10,000), polyoxymethylene, polytetrahydrofuran, polyvinyl alcohols and their esters such as polyvinyl acetate (with any degree of saponification), polyvinylpyrilidone, polyvinylimine, polyacrylic acids and their esters such as polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, poly-tert-butyl methacrylate, polyisobutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, poly-tert-butyl acrylate, polyisobutyl acrylate, their blends and copolymers, but also
  • polyvinyl alcohol-co-polyvinyl acetate polymethyl methacrylate-co-polymethyl acrylate or polymethyl methacrylate-co-polybutyl acrylate
  • Advantageous binders can be burned off residue-free and controlled, such as polyvinyl alcohol, polyacetal and polyvinyl acetate.
  • compositions of the two individual polymers such as mixtures comprising polyvinyl alcohol and polyvinyl acetate
  • Polymethyl methacrylate and polymethyl acrylate or polymethyl methacrylate and polybutyl acrylate are advantageously present as suspensions or dispersions of the polymers in water and are added together, simultaneously or sequentially with respect to the addition of the carboxylic acid (s), advantageously sequentially after the addition of the carboxylic acids.
  • the content of binder is in the range from 0.1% by weight to 7% by weight, preferably from 0.1% by weight to 5% by weight, particularly preferably from 0.5% by weight to 3 Wt .-%, based on the finished powder.
  • the pH value has to be simulated with caustic soda, potassium hydroxide solution, gaseous ammonia or ammonia water , or it must be used (advantageously with ammonia) partially neutralized carboxylic acid preparations, ie salts.
  • the required degree of neutralization can be determined by the average person skilled in the art by following the zeta potential of the dispersion.
  • combination 7.005 means the combination of the carboxylic acids as in Table 1, Item No. 5 with the form shown in Table 7, in which Carboxylic acid is present (here: free carboxylic acid) and listed in Table 7 binder (here: polyvinyl acetate).
  • oxalic acid is used as a long-chain carboxylic acid, stearic acid as a short-chain carboxylic acid and polyvinyl acetate as a binder, wherein the oxalic acid is used as a free carboxylic acid.
  • Table 7 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid.
  • the binder used in each case is polyvinyl acetate.
  • Table 8 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • the binder used in each case is polyvinyl acetate.
  • Table 9 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • the binder used in each case is polyvinyl acetate.
  • Table 10 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as a zirconium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • the binder used in each case is polyvinyl acetate.
  • Table 11 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the ammonium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • the binder used in each case is polyvinyl acetate.
  • Table 12 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt, and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • the binder used in each case is polyvinyl acetate.
  • Table 13 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid.
  • a binder polyvinyl alcohol is used in each case.
  • Table 14 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • a binder polyvinyl alcohol is used in each case.
  • Table 15 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • a binder polyvinyl alcohol is used in each case.
  • Table 16 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as a zirconium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • a binder polyvinyl alcohol is used in each case.
  • Table 17 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as ammonium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • a binder polyvinyl alcohol is used in each case.
  • Table 18 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the yttrium salt, and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • a binder polyvinyl alcohol is used in each case.
  • Table 19 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid. In each case polyacrylic acid is used as the binder.
  • Table 20 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • polyacrylic acid is used as the binder.
  • Table 21 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt. In each case polyacrylic acid is used as the binder.
  • Table 22 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a zirconium salt and wherein Carboxylic acids with several acid functions all acid functionally present as salt. In each case polyacrylic acid is used as the binder.
  • Table 23 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the ammonium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt. In each case polyacrylic acid is used as the binder.
  • Table 24 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt, and wherein carboxylic acids having multiple acid functions all acid functions as a salt. In each case polyacrylic acid is used as the binder.
  • Table 25 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid. Polymethylmethacrylate is used as binder in each case.
  • Table 26 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt. Polymethylmethacrylate is used as binder in each case.
  • Table 27 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described in Table 1 above, wherein the short-chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt. Polymethylmethacrylate is used as binder in each case.
  • Table 28 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as zirconium salt and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • Polymethylmethacrylate is used as binder in each case. Table 29
  • Table 29 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the ammonium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt. Polymethylmethacrylate is used as binder in each case.
  • Table 30 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt, and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt. Polymethylmethacrylate is used as binder in each case.
  • Table 31 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid.
  • polyethylene glycol molecular weight 3000 is used as the binder.
  • Table 32 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • polyethylene glycol molecular weight 3000 is used as the binder.
  • Table 33 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • polyethylene glycol molecular weight 3000 is used as the binder.
  • Table 34 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as a zirconium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • polyethylene glycol molecular weight 3000 is used as the binder.
  • Table 35 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the ammonium salt and wherein Carboxylic acids with several acid functions all acid functionally present as salt.
  • polyethylene glycol molecular weight 3000 is used as the binder.
  • Table 36 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the yttrium salt, and with multiple acid carboxylic acids all acid functions are present as a salt.
  • polyethylene glycol molecular weight 3000 is used as the binder.
  • Table 37 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the free carboxylic acid.
  • binder in each case polyvinylimine is used.
  • Table 38 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the sodium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polyvinylimine is used.
  • Table 39 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polyvinylimine is used.
  • Table 40 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the zirconium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polyvinylimine is used.
  • Table 41 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as ammonium salt and wherein carboxylic acids having multiple acid functions all acid functions as a salt.
  • binder in each case polyvinylimine is used.
  • Table 41 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt, and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • binder in each case polyvinylimine is used.
  • Table 42 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid.
  • the binder used in each case is polymethyl methacrylate-polymethyl acrylate blend.
  • Table 43 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • the binder used in each case is polymethyl methacrylate-polymethyl acrylate blend.
  • Table 44 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the potassium salt and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • the binder used in each case is polymethyl methacrylate-polymethyl acrylate blend.
  • Table 45 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as a zirconium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • the binder used in each case is polymethyl methacrylate-polymethyl acrylate blend.
  • Table 46 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the ammonium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • the binder used in each case is polymethyl methacrylate-polymethyl acrylate blend.
  • Table 47 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt, and wherein Carboxylic acids with several acid functions all acid functionally present as salt.
  • the binder used in each case is polymethyl methacrylate-polymethyl acrylate blend.
  • Table 48 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as a free carboxylic acid.
  • binder polybutyl acrylate-polymethyl methacrylate blend is used.
  • Table 49 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and carboxylic acid having multiple acid functions all acid functions as a salt.
  • binder polybutyl acrylate-polymethyl methacrylate blend is used.
  • Table 50 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • binder polybutyl acrylate-polymethyl methacrylate blend is used.
  • Table 51 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as a zirconium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polybutyl acrylate-polymethyl methacrylate blend is used.
  • Table 52 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the ammonium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polybutyl acrylate-polymethyl methacrylate blend is used.
  • Table 53 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as yttrium salt, and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • binder polybutyl acrylate-polymethyl methacrylate blend is used.
  • Table 54 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the free carboxylic acid.
  • binder in each case polybutylmethacrylate is used.
  • Table 55 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as the sodium salt and wherein carboxylic acids having a plurality of acid functions all acid functions as a salt.
  • binder in each case polybutylmethacrylate is used.
  • Table 56 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the potassium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polybutylmethacrylate is used.
  • Table 57 consists of 700 combinations of the long-chain and short-chain carboxylic acids as described above in Table 1, wherein the short-chain carboxylic acid is present as zirconium salt and wherein
  • Carboxylic acids with several acid functions all acid functions as salt.
  • binder in each case polybutylmethacrylate is used.
  • Table 58 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the ammonium salt and wherein carboxylic acids having multiple acid functions are all acid functions as a salt.
  • binder in each case polybutylmethacrylate is used.
  • Table 59 consists of 700 combinations of the long and short chain carboxylic acids as described in Table 1 above wherein the short chain carboxylic acid is present as the yttrium salt, and where multiple acid carboxylic acids are all acid functions as a salt.
  • binder in each case polybutylmethacrylate is used.
  • the BET specific surface area of the finished, binder-free powder is 3 m 2 / g to 70 m 2 / g, preferably 7 m 2 / g to 30 m 2 / g, particularly preferably 10 m 2 / g to 25 m 2 /G. Measured here is the BET specific surface area after burnout of the organic adjuvants without pressing the powder.
  • Both types of powders known as industrial raw materials, are known to achieve strengths above 900 MPa in accordance with ISO 843, but can not be processed green reliably and can not be processed by means of net shape technology.
  • the starting material was a 3 Mo 1% Y2O3 teilstablomes zirconia powder with a specific surface area of 16 m2 / g and a monoclinic phase content of 42%, dispersed in demineralized water.
  • the following parameters for grain distribution were measured by laser diffraction (Coulter Counter) using the Mie model: D50 70 nm, D90 170 nm. The value for D50 was confirmed by a field emission electron microscope.
  • the solids content of the dispersion corresponded to 50% by weight and the pH was 9.
  • An aqueous, partially neutralized preparation of a short-chain carboxylic acid having a pH of 5 was added to this dispersion with vigorous stirring so that 0.5 kg of zirconium oxide was added to 100 kg Carboxylic acid omitted. During the addition, the suspension had room temperature. After the addition was continued stirred, and the pH determined to be 9.8. Then an aqueous, unneutralized carboxylic acid preparation was added, so that accounts for 100 kg of zirconia 2 kg of carboxylic acid. Stirring was continued and the pH was determined to be 8.5.
  • the bulk density and the tap density were determined, and the ratio was formed. A value of 1.24 was determined. This value indicates a very good compaction behavior. 50% of the theoretical density is already reached at 76 MPa.
  • the green strengths are approximately 50% above the values of the comparative samples from Example 1, the cohesivities of over 1 are sufficient for net shape technology via axial pressing. The green workability was very good.
  • Example 2 The dispersion of zirconium oxide in water described in Example 2 was added to an aqueous carboxylic acid preparation, as described in Example 2, so that 3 kg of carboxylic acid are accounted for per 100 kg of zirconium oxide. Then 2.75 kg of polymethyl methacrylate in the form of an aqueous dispersion was added to 100 kg of zirconium oxide, and the resulting formulation was converted into granules by spray-drying. The following values were obtained with this granulate:
  • the bulk density according to ASTM B329 and the tap density were determined, and the ratio was formed. A value of 1.25 was determined. This value indicates a good compaction behavior. 50% of the theretical density is already reached at 55 MPa. The cohesiveness is very high, but the green strength is worse compared to example 3. The sliding coefficient is comparatively high.
  • the Hausner ratio was 1, 31. However, very high compression pressures are required to reach 50% of the theoretical density (> 178 MPa). Cohesiveness and green workability were very good.
  • compacts for bending fracture test according to ISO 843 were prepared by cold isostatic pressing at 1950 bar. After thermal debindering and sintering at 1475 ° C. for 5 h, the following values were obtained: density 6.08, 4-point bending strength 848 MPa.
  • Examples 2 and 5 show the balance of the formulation of Example 2 in terms of processability and strength of the sintered body.
  • the formulation of Examples 3 and 4 show too low strength, Example 4 macropores and the lowest sintered density.
  • Examples 1 to 5 show in direct comparison that the formulation of the present invention, when the binder to carboxylic acid ratio is properly adjusted, results in an optimally formulated zirconia, with both residual porosity, strength and residual pore content in the sintered article and all parameters important for the processability of the powder, are balanced and optimal.
  • the results can be applied to other zirconia powders, taking into account their specific surface area. In practice, it will therefore always be necessary to determine experimentally the optimum content of carboxylic acid. Typical contents are between 0.1 and 5 percent by weight, more preferably between 0.5 and 4 percent by weight.
  • carboxylic acid preparations a long-chain and a short-chain carboxylic acid are used in the appropriate amounts.
  • the long-chain carboxylic acid is used as the free acid
  • the short-chain carboxylic acid as the ammonium salt, potassium salt or free acid.
  • the binders are also indicated, these are added in the form of an aqueous dispersion or solution. The respective combinations are given in the following table:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Composite Materials (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Colloid Chemistry (AREA)

Abstract

L'invention concerne une formulation d'oxyde de métal valve contenant des agents auxiliaires organiques. La pression de compression nécessaire à l'obtention d'une densité à cru d'au moins 50 % de la densité théorique est de 200 MPa ou moins, et la force nécessaire à la destruction de la pièce moulée, dans la direction axiale et la direction radiale, est de 10 MPa ou plus. L'invention concerne également un procédé de fabrication de ladite formulation.
EP09781550A 2008-08-26 2009-08-06 Formulation d'oxyde de métal valve Withdrawn EP2318325A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008039668A DE102008039668B4 (de) 2008-08-26 2008-08-26 Ventilmetalloxidformulierung und Verfahren zu ihrer Herstellung
PCT/EP2009/060194 WO2010026016A2 (fr) 2008-08-26 2009-08-06 Formulation d'oxyde de métal valve

Publications (1)

Publication Number Publication Date
EP2318325A2 true EP2318325A2 (fr) 2011-05-11

Family

ID=41394869

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09781550A Withdrawn EP2318325A2 (fr) 2008-08-26 2009-08-06 Formulation d'oxyde de métal valve

Country Status (5)

Country Link
US (1) US20110160036A1 (fr)
EP (1) EP2318325A2 (fr)
JP (1) JP5456044B2 (fr)
DE (1) DE102008039668B4 (fr)
WO (1) WO2010026016A2 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015102763A1 (de) * 2015-02-26 2016-09-01 Vacuumschmelze Gmbh & Co. Kg Verfahren zum Herstellen eines thermoelektrischen Gegenstands für eine thermoelektrische Umwandlungsvorrichtung
JP6461833B2 (ja) * 2016-01-27 2019-01-30 信越化学工業株式会社 透明焼結体の製造方法
EP4001243A1 (fr) * 2020-11-17 2022-05-25 Element 22 GmbH Procédé de fabrication de corps moulés par frittage
CN116648430B (zh) * 2020-12-22 2024-11-26 可乐丽则武齿科株式会社 氧化锆颗粒、压粉体和它们的制造方法

Family Cites Families (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2053627C3 (de) * 1970-10-31 1985-01-24 Rheinisch-Westfälische Kalkwerke AG, 5600 Wuppertal Verfahren zur Herstellung von hydrophoben festen, insbesondere pulverförmigen, Öle, bitumöse Stoffe oder Wachse in feiner Verteilung enthaltenden Hydroxiden
JPS59128265A (ja) * 1983-01-14 1984-07-24 株式会社クラレ 高強度セラミツク成形体の製造法
JPS63265849A (ja) * 1987-04-24 1988-11-02 Honda Motor Co Ltd セラミツクス成形体用成形材料
JP2614880B2 (ja) * 1987-12-24 1997-05-28 イビデン株式会社 セラミックス顆粒の製造方法
US5089455A (en) * 1989-08-11 1992-02-18 Corning Incorporated Thin flexible sintered structures
DE4336694A1 (de) * 1993-10-27 1995-05-04 Inst Neue Mat Gemein Gmbh Verfahren zur Herstellung von Metall- und Keramiksinterkörpern und -schichten
DE19547183A1 (de) * 1995-01-31 1996-08-01 Bosch Gmbh Robert Keramische Pulver mit hydrophobierter Oberfläche sowie deren Herstellung und Verwendung
WO1996023744A1 (fr) * 1995-01-31 1996-08-08 Robert Bosch Gmbh Poudres ceramiques a surface rendue hydrophobe, leur fabrication et leur utilisation
JP3680338B2 (ja) * 1995-02-15 2005-08-10 東ソー株式会社 ジルコニア顆粒の製造方法
US6068828A (en) * 1997-06-13 2000-05-30 Nippon Shokubai Co., Ltd. Zirconia powder, method for producing the same, and zirconia ceramics using the same
US5900201A (en) * 1997-09-16 1999-05-04 Eastman Kodak Company Binder coagulation casting
JP2001089145A (ja) * 1999-09-24 2001-04-03 Toray Ind Inc ジルコニア粉末
US20040179994A1 (en) * 2003-01-21 2004-09-16 Fenouil Laurent Alain Zirconia extrudates
JP2006027914A (ja) * 2004-07-12 2006-02-02 Toray Ind Inc プレス成形用セラミックス顆粒
DE102004061697A1 (de) * 2004-12-22 2006-07-06 Degussa Ag Dispersion von Zirkondioxid und Zirkon-Mischoxid
US7452481B2 (en) * 2005-05-16 2008-11-18 Kabushiki Kaisha Kobe Seiko Sho Polishing slurry and method of reclaiming wafers
JP2007197265A (ja) * 2006-01-27 2007-08-09 Toray Ind Inc プレス成形用セラミックス顆粒、およびセラミックス顆粒の充填方法
CN101500943B (zh) * 2006-08-17 2012-07-18 H.C.施塔克有限公司 氧化锆及其生产方法
DE102006055975A1 (de) * 2006-11-24 2008-05-29 Evonik Degussa Gmbh Granulate von Metallen und Metalloxiden

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2010026016A2 *

Also Published As

Publication number Publication date
DE102008039668B4 (de) 2013-03-28
JP2012500770A (ja) 2012-01-12
WO2010026016A3 (fr) 2010-04-29
WO2010026016A2 (fr) 2010-03-11
US20110160036A1 (en) 2011-06-30
DE102008039668A1 (de) 2010-03-25
JP5456044B2 (ja) 2014-03-26

Similar Documents

Publication Publication Date Title
EP2819973B1 (fr) Procédé de fabrication d'un corps moulé fritté céramique composé d'oxyde de zircon stabilisé par y2o3
DE3610041C2 (de) Keramik auf Zirkoniumdioxidbasis mit Aluminiumoxid, Spinell, Mullit oder Spinell und Mullit und mit verbesserter hydrothermaler und thermischer Stabilität
US20100048376A1 (en) Granules of metals and metal oxides
DE4126738A1 (de) Zr0(pfeil abwaerts)2(pfeil abwaerts)-haltiger keramikformkoerper
WO1995028364A2 (fr) Produit fritte d'al2o3, son procede de production et son utilisation
DE102008039668B4 (de) Ventilmetalloxidformulierung und Verfahren zu ihrer Herstellung
DE102006051661A1 (de) Zubereitung zur Herstellung feuerfester Materialien
DE2163917A1 (de) Verfahren zur Herstellung von Rohlingen für die Erzeugung von Aluminiumoxidkeramiken
WO2015014930A1 (fr) Sphères frittées
EP2462080B1 (fr) Materiau fritté à base d' alpha-alumine et procedé pour la produktion d' un produit faconné, microcristallin de haute densité à partir de ce materiau et son utilisation.
DE102012200654B4 (de) Schlicker, Granulat und Keramik, Verfahren zu deren Herstellung und Verwendung
DE2123045A1 (de) Verfahren zur Herstellung von feinteiligen Metalloxiden und deren Verwendung zur Herstellung von gesinterten hitzebeständigen Formteilen
DE102005020781A1 (de) Zirkondioxid und Aluminiumoxid enthaltender Schlicker und daraus erhältlicher Formkörper
DE69800047T2 (de) Verfahren zum Herstellen von Grünkörpern
DE102009046036B4 (de) Verfahren zur Herstellung von redispergierbaren hochreinen Nanospinellpulvern und redispergierbares hochreines Nanospinellpulver
DE102008019529B4 (de) Feuerfestes keramisches Erzeugnis und zugehöriges Formteil
DE69003717T2 (de) Verfahren zur Herstellung teilchenförmiger keramischer Materialien.
EP0610848B1 (fr) Procédé de fabrication de pièces ceramiques frittées dense en nitrure de silicium ayant une résistance mécanique élévée
EP4392388A1 (fr) Procédé de production d'oxyde de zirconium granulaire
DE19733700C2 (de) Hartstoffverstärkte stabilisierte Zr02-Keramik mit mechanischer Stabilität unter hydrothermaler Beanspruchung, Verfahren zu deren Herstellung und Verwendung
WO2014048586A1 (fr) Mélange pour formation d'un matériau réfractaire, matériau réfractaire, procédé de fabrication d'un matériau réfractaire et utilisation d'une substance comme agent auxiliaire de frittage
DE102012200652B4 (de) Schlicker, Granulat und Keramik, Verfahren zu deren Herstellung und Verwendung
DE4422632C2 (de) Verfahren und Verwendung einer Terpolymers zur Herstellung eines Oxidkeramik-Materials
WO2018167128A1 (fr) Procédé de métallurgie des poudres pour réaliser une ébauche dentaire
DE102010032174B4 (de) Verfahren zur Herstellung von stäbchenverstärkten Keramiken, Keramikwerkstoff und seine Verwendung, Pulverwerkstoff, Granulat, sowie vorgesinterter Körper

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20110328

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

AX Request for extension of the european patent

Extension state: AL BA RS

DAX Request for extension of the european patent (deleted)
17Q First examination report despatched

Effective date: 20140123

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20160920