Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
  • B05B7/14—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas designed for spraying particulate materials
  • B05B7/1481—Spray pistols or apparatus for discharging particulate material
  • B05B7/1486—Spray pistols or apparatus for discharging particulate material for spraying particulate material in dry state
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
  • C03B11/06—Construction of plunger or mould
  • C03B11/08—Construction of plunger or mould for making solid articles, e.g. lenses
  • C03B11/084—Construction of plunger or mould for making solid articles, e.g. lenses material composition or material properties of press dies therefor
  • C03B11/086—Construction of plunger or mould for making solid articles, e.g. lenses material composition or material properties of press dies therefor of coated dies
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B40/00—Preventing adhesion between glass and glass or between glass and the means used to shape it, hold it or support it
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B40/00—Preventing adhesion between glass and glass or between glass and the means used to shape it, hold it or support it
  • C03B40/02—Preventing adhesion between glass and glass or between glass and the means used to shape it, hold it or support it by lubrication; Use of materials as release or lubricating compositions
  • C03B40/027—Apparatus for applying lubricants to glass shaping moulds or tools
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B9/00—Blowing glass; Production of hollow glass articles
  • C03B9/30—Details of blowing glass; Use of materials for the moulds
  • C03B9/48—Use of materials for the moulds
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/02—Coating starting from inorganic powder by application of pressure only
  • C23C24/04—Impact or kinetic deposition of particles
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
  • C23C24/082—Coating starting from inorganic powder by application of heat or pressure and heat without intermediate formation of a liquid in the layer
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
  • C23C24/082—Coating starting from inorganic powder by application of heat or pressure and heat without intermediate formation of a liquid in the layer
  • C23C24/085—Coating with metallic material, i.e. metals or metal alloys, optionally comprising hard particles, e.g. oxides, carbides or nitrides
  • C23C24/087—Coating with metal alloys or metal elements only
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2215/00—Press-moulding glass
  • C03B2215/02—Press-mould materials
  • C03B2215/08—Coated press-mould dies
  • C03B2215/10—Die base materials
  • C03B2215/11—Metals

Definitions

• TITLE Surface treatment of a metal surface of a metal part, such as a glassware mold, by cold spraying of a metal powder.
• This application generally concerns metal castings in the field of glassmaking, in particular cast iron, brass, bronze (and other alloys comprising copper and tin) or steel moulds used to make glass objects such as bottles or, in general, any metal part likely to come into contact with the parison.
• the present application relates more particularly to the surface treatment of the metal surface of these metal parts which comes into contact with the glass parison (or gob) during the manufacture of glass objects. It finds a particular, but not limiting, application in the surface treatment of the molding surfaces of molds in order to improve the thermal and/or mechanical properties of the molds during the roughing and finishing phase.
• the manufacture of a glass object is done in several stages.
• viscous glass is melted (at a temperature between 700 °C and 1200 °C), cast in the form of a parison (drop), fed via a deflector and a distribution channel, into a mold, called a roughing mold.
• the viscous glass undergoes compression in the roughing mold and is then pierced in order to bring it into contact with the walls of the roughing mold and obtain a roughing.
• the roughing then has a temperature of up to 900 °C, depending on the area and thickness of the roughing.
• the blank thus formed is transferred into a finishing mold to be blown and give it its final shape.
• a second stage called finishing the blank thus formed is transferred into a finishing mold to be blown and give it its final shape.
• a significant decrease in temperature occurs as well as an elongation of the glass.
• the final product is obtained after this blowing stage. It then has a temperature of around 600°C.
• Glassware molds thus have several functions.
• glass molds have a thermal function by allowing the glass to cool. It is necessary that, when it leaves the blank mold, the blank is sufficiently cooled to retain its shape. To this end, the blank should remain in the blank mold for a sufficient time to allow the dissipation of a quantity of heat allowing the glass to reach the desired viscosity. It is easy to understand that This amount of heat increases with the weight of the blank, which, at constant thermal conductivity, normally leads to an increase in the residence time in the blank mold. Added to this is the fact that, during the finishing stage, the molding surface of the mold will heat up via the heat transfer between the core of the blank and its surface.
• moulds made of copper and tin alloys, particularly bronze have been proposed, which have good thermal conductivity.
• these moulds are very expensive.
• glassware molds have a geometric function since they give the article its final shape.
• this function is undermined by mold wear issues.
• These molds most often made of cast iron, bronze (and other alloys including copper and tin), or steel (in particular iron-carbon steels, stainless steels, refractory steels), tend to wear quickly, particularly in areas such as the joint plane (or seam), the bottom, the ring or even the neck of the mold, due to an abrasion and/or corrosion phenomenon due to the presence of silica in the glass.
• known hardfacing techniques are not entirely satisfactory, since they only treat the edges and not the entire molding surface. In fact, treating the entire molding surface with these known techniques leads to a high risk of mold cracking. Known hardfacing techniques therefore do not completely prevent mold wear, which must therefore be replaced regularly.
• An aim of the present application is to remedy at least in part the aforementioned drawbacks.
• the invention relates, according to a first aspect, to a surface treatment method for treating a metal surface of a metal part configured to come into contact with a parison, for example a molding surface of a glassware mold, the surface treatment method comprising the following steps: cold spraying of a metal powder in the solid state onto the metal surface so as to obtain a solid deposit; and machining the solid deposit so as to obtain a coating.
• the metal powder is projected using a projection gas subjected to a pressure greater than thirty bars, for example between forty bars and seventy bars, for example around fifty bars;
• the metal powder is projected using a projection gas heated to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C;
• a projection distance corresponding to a distance between a nozzle for projection of the metal powder and the metal surface, is between 15 millimeters and 60 millimeters, preferably between 15 and 35 millimeters, for example equal to approximately 20 millimeters or approximately 30 millimeters;
• a speed of movement of a nozzle for projection of the metal powder during projection is between 200 millimeters per second and 1000 millimeters per second, for example between 200 and 450 millimeters per second;
• the projection step is carried out for a sufficient time to obtain a solid deposit having a thickness of between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 2.5 millimeters;
• an injection flow rate of the metal powder into the projection gas is between 1 and 10 cm 3 /min, preferably between 2 and 3 cm 3 /min, for example of the order of 2.5 cm 3 /min;
• the coating has better mechanical resistance than the metal surface, in particular better resistance to abrasion
• the coating has a higher thermal conductivity than the metal surface
• the metal powder consists essentially of NiCr powder; and/or - the metal powder is essentially composed of, by mass relative to the total mass of the powder:
• a metal part for example a glassware mold, comprising: a metal surface configured to come into contact with a parison; and a coating covering all or part of the metal surface and comprising a metal alloy resulting from the cold projection of a metal powder onto the metal surface in accordance with a surface treatment method according to the first aspect.
• the metal surface comprises at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, a copper-tin based alloy such as bronze, iron-carbon steel, refractory steel or stainless steel, brass;
• the metal powder is mainly composed of nickel and chromium
• the coating is obtained by cold spraying of a metal powder essentially consisting of NiCr powder or of a metal powder essentially consisting of, by mass relative to the total mass of the powder:
• the part comprises a glassware mold, the metal surface corresponding to the molding surface of the glassware mold and comprising at least one of the following materials: graphite cast iron with lamellar, vermicular or spheroidal micrographitic structure, iron-carbon steel, refractory steel or stainless steel.
• an installation is proposed comprising:
• a machine for surface treatment of a glassware mold comprising: a support configured to receive a metal part, for example a glassware mold, having a metal surface configured to come into contact with a parison; and a projection nozzle configured to cold project a metal powder in the solid state onto the metal surface so as to obtain a solid deposit, and a machining station configured to machine the solid deposit and obtain a coating.
• FIG. 1 schematically illustrates an example of an installation for the metal surface treatment of a metal part according to an embodiment
• FIG. 2 is a flowchart illustrating steps of a method for surface treatment of a metal part according to an embodiment
• FIG. 3 is a schematic sectional view of a glassware mold comprising a coating according to an embodiment.
• the present disclosure will be more particularly described in the case of the surface treatment of the molding surface 2 of a glassware mold 1. This is however not limiting, the present disclosure applying to the surface treatment of any metal surface of a metal part configured to come into contact with the parison.
• the present application relates to the surface treatment of all or part of the molding surface 2 of a glassware mold 1.
• the glassware mold 1 may in particular comprise a blank mold 1 configured to receive a drop of glass (parison) and form a blank.
• the molding surface 2 corresponds to the surface of the mold 1 likely to come into contact with the parison during the molding process.
• the molding surface 2 may in particular comprise at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, bronze (and other alloys comprising copper and tin), steel of the iron-carbon steel type, refractory steel or stainless steel, brass.
• the glassware mold 1 is formed entirely from the same constituent material as the molding surface 2.
• it is proposed to cold spray and at a very high speed, by a high-pressure spray gas 3 transporting it, a metal powder 4 onto all or part of the molding surface 2.
• Cold and high-pressure projection known by its English name of “cold spray”, makes it possible to obtain a deposit density very close to the theoretical density of the solid metallic material constituting the powder, without heating the molding surface 2 during deposition, which avoids modifying the metallurgical quality of the molding surface 2 and the solid deposit 5. It also makes it possible to obtain high thicknesses of deposits (up to several millimeters) with low roughness and a material yield of more than 90%, as well as high interparticle cohesion. In addition, the implementation of this cold projection does not require a prior step of preparing the molding surface 2 or masking the mold 1 to be treated.
• FIG. 1 An installation 9 intended for this treatment of all or part of the molding surface 2 of a glassware mold 1 is shown in Figure 1.
• This installation 9 comprises a surface treatment machine 10 and a machining station 11.
• the surface treatment machine 10 is configured to cold spray the metal powder 4, in solid form, onto the molding surface 2 of the mold 1.
• a convergent-divergent nozzle 8 placed downstream of the injection system 18 and configured to accelerate the projection gas 3 when it transports the metal powder 4, the divergent part of the nozzle 8 forming a deposition tube 14;
• a cooling system 15 which may comprise a conduit which surrounds the deposition tube 14 in order to cool the projection gas 3, which transports the metal powder 4, by conduction by circulating a cooling fluid around the deposition tube 14; the fluid cooling may in particular comprise distilled water at a temperature lower than the temperature of the projection gas 3, typically at a temperature between 8 and 20°C.
• the projection nozzle 7 has an outlet diameter (at the free end of the deposition tube 14) of between two and ten millimeters, for example of the order of six millimeters.
• the surface treatment machine 10 further comprises a support 17 configured to fix the glassware mold 1 relative to the spray nozzle and actuators (not shown) configured to move the spray nozzle 7 relative to the molding surface 2 in the three spatial directions.
• actuators can move the spray nozzle 7, the support 17 on which the mold 1 is mounted or both the spray nozzle 7 and the support 17.
• the actuators are configured to move the nozzle 7 relative to the molding surface 2 at a speed of between 200 millimeters per second (mm/s) and 1000 millimeters per second (mm/s).
• the scanning speed is between 200 and 450 mm/s (to within 5%).
• the actuators are further configured to shift the impact zone by a distance of between 0.5 millimeters and 2.5 millimeters (no scanning between two adjacent cords), for example of the order of one or two millimeters (to within 10%).
• the heating system is configured to heat the projection gas 3 to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C.
• the projection gas 3 is furthermore pressurized in the pressurization chamber to a pressure greater than or equal to thirty-five bars, preferably between forty bars and seventy bars, for example of the order of fifty bars.
• the spray nozzle 7 can be controlled by a remote control station 16, placed near the surface treatment machine 10 or remotely.
• the machining station 11 comprises a support configured to receive the mold 1 coated with the solid deposit 5 and a machining tool, such as a milling machine, configured to machine the solid deposit 5 and obtain the coating 6.
• a machining tool such as a milling machine
• the machining tool can be handled by an operator or mounted on the installation 8 and controlled by a remote control station, for example the same control station 16 of the projection nozzle 7.
• a method 100 for treating the casting surface 2, implemented by the surface treatment installation 9, is shown in Figure 2. It comprises the following steps:
• the method 100 can be applied to the entire molding surface 2 of the mold 1 or to only part of this surface 2.
• a high-temperature (typically nitrogen or helium) and high-pressure spray gas 3 is used to propel the metal powder 4 at a supersonic speed (greater than 300 m/s) onto the molding surface 2 to create a solid deposit 5 intended to form the coating 6 by impact of the metal powder 4 onto the molding surface 2, the impact force ensuring the quality of the deposit.
• the deposit is said to be “solid” to the extent that the grains of the metal powder 4 remain in the solid state throughout the spraying and adhesion step 110 to the molding surface 2, as opposed to processes in which the temperature of the metal powder 4 exceeds its melting temperature such that all or part of the powder 4 melts at some point during the process.
• the metal powder 4 comes into contact at high speed with the molding surface 2, it mechanically adheres to the molding surface 2 by plastic deformation with strong adhesion, which makes it possible to avoid defects linked to high temperatures such as oxidation, residual stresses, phase transformations, etc.
• the solid deposit 5 is then integral with the molding surface 2, that is to say that it can only be separated from the molding surface 2 by being completely or partially damaged.
• the projection step 110 is said to be cold insofar as the metal powder 4 is not heated before or during deposition, other than by its contact with the projection gas 3 or the molding surface 2.
• the projection gas 3 is heated and pressurized in order to ensure that the metal powder 4 is projected at a projection speed (speed of the metal powder 4 at the outlet of the nozzle 7) capable of allowing the plastic deformation of the metal powder 4 during its impact against the contact surface.
• a projection speed speed of the metal powder 4 at the outlet of the nozzle 7
• said projection speed is greater than or equal to the critical speed of the metal powder 4.
• This critical speed corresponds to the speed from which the attachment (adhesion) of the solid deposit 5 is possible: when the impact speed is lower than the critical speed of the material, then the particles of metal powder 4 do not deform plastically and can rebound and/or erode the molding surface 2.
• the critical speed depends on the nature of the material and the size of the grains of the metal powder 4.
• the speed critical is for example higher in the case of a metal powder 4 comprising a hard material, such as a titanium dioxide-based material (above 1250 m/s), than in the case of a metal powder 4 comprising a ductile material, such as a copper-based material (of the order of 600 m/s).
• An equation E1 for determining the critical speed of a material has been demonstrated by T. Schmidt, F.
• Tj is the initial temperature of the material to be characterized
• T m is the melting temperature of the material to be characterized;
• c p is the specific heat;
• T r is a reference temperature equal to 293 K
• Fi and F2 are calibration coefficients used to recalibrate the calculated value to measured speed values.
• the pressure applied to the projection gas 3 is therefore chosen so as to exceed the critical speed of the metal powder 4 used for the solid deposition 5.
• the temperature to which the projection gas 3 is heated is typically greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C.
• This heating temperature is advantageously at least 300°C below the melting temperature of the constituent of the metal powder 4 with the lowest melting temperature and for example between 300 and 700°C below this melting temperature.
• the projection gas 3 can further be accelerated by the configuration of the projection nozzle 7 (modification of the gas passage section, for example in a convergent-divergent nozzle 8, etc.).
• the critical speed is for example of the order of 574 m/s.
• the projection gas 3 can be cooled downstream of the point of injection of the metal powder 4 into the gas in order to ensure that the metal powder 4 remains solid without reducing the projection speed of the powder.
• the projection step 110 is carried out so as to obtain a solid deposit 5 whose thickness is sufficient to allow machining of the solid deposit 5 and obtaining of the coating 6.
• This thickness of the solid deposit 5 is typically between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 2.5 millimeters.
• the thickness of the coating 6 (after machining) can thus be between 0.1 millimeters and 1.5 millimeters.
• the molding surface 2 is moved relative to the surface treatment machine 10 during the projection step 110 in order to produce a deposit on all or part of the molding surface 2.
• the projection nozzle 7 can be moved while the glassware mold 1 is fixed, or alternatively the glassware mold 1 can be moved while the projection nozzle 7 is fixed, or both the projection nozzle 7 and the glassware mold 1 are moved.
• the relative movement speed and the number of passes over a given surface determine the thickness of the deposit.
• the relative movement speed of the spray nozzle 7 and the molding surface 2 of the glassware mold 1 may be between 200 millimeters per second (mm/s) and 1000 millimeters per second (mm/s), for example of the order of 200 millimeters per second (mm/s) to 450 millimeters per second (mm/s) (to within 5%).
• the flow rate of supply of the metal powder 4 by the distributor 13 is between 1 and 10 cm 3 /min, preferably between 2 and 3 cm 3 /min, for example of the order of 2.5 cm 3 /min.
• the metal powder 4 thus supplied is entirely transported by the carrier gas to the injection system 18, so that this supply flow rate also constitutes an injection flow rate of the metal powder 4 into the projection gas 3 by the injection system 18.
• the flow rate of carrier gas is typically between 2.0 and 6.0 cubic meters per hour (m 3 /h), for example of the order of 4.0 or 4.5 cubic meters per hour (m 3 /h).
• the size (width of the bead) of the solid deposit 5 is preferably between 0.5 millimeters and two millimeters, for example of the order of one millimeter (to within 10%). This size depends on the distance between the outlet of the projection nozzle 7 of the surface treatment machine 10 and the molding surface 2 and on the outlet diameter of the projection nozzle 7. In order to obtain the aforementioned solid deposit size, said distance is typically between fifteen millimeters and sixty millimeters, preferably between fifteen millimeters and thirty-five millimeters, for example equal to approximately twenty millimeters or approximately thirty millimeters, for an outlet diameter of the projection nozzle 7 of between two and ten millimeters, for example of the order of six millimeters.
• the scanning pitch (distance between the centers of two adjacent solid deposit beads 5) is between 0.5 millimeters and two millimeters, for example of the order of one millimeter (to within 10%). It is preferably substantially equal to the size of the solid deposit 5.
• the metal powder 4 preferably comprises 75% by mass or more, advantageously at least 80% by mass, of spherical grains, relative to the total mass of the powder.
• Laser particle size is measured according to ISO 13320:2019.
• the diameter of the grains of the powder is advantageously between 10 and 50 pm, in particular between 12 and 45 pm, and preferably has a D50 value between 20 and 30 pm.
• the melting temperature of the powder components is typically higher than the parison temperature - which can reach 1100 °C - in order to avoid thermal degradation of the coating 6 during molding.
• the melting temperature of the powder component having the lowest melting temperature is 300 °C higher than the parison temperature.
• the "tapped density” is evaluated according to the bases of the NF EN ISO 3923 (2016) standard relating to "Metal powders - Determination of the apparent density after tamping". Typically, a test tube with a volume of 25 cm3 and a KERN SEAL balance with a maximum capacity of 6000 g and a resolution of 0.1 g are used. The tamping is stopped after 3000 strokes.
• the "yray density” is evaluated according to the bases of the standard NF EN ISO 8130-2 (2011) relating to "Powders for coating - Determination of the density using a gas pycnometer (reference method)".
• a helium pycnometer (Quantachrome Upyc 1200 e) with a 10 cm 3 cell is used.
• the mass of the powder is measured with a balance, for example METTLER TOLEDO AB104 with a maximum capacity of 110 g and a resolution of 0.1 mg.
• the tapped density of metal powder is typically between 3 and 7 g/ cm3 .
• the true density is typically between 6 and 10 g/cm 3 , preferably with a low standard deviation, for example 0.001.
• Metal powders having such a true density in fact make it possible to obtain a denser solid deposit 5 .
• a powder is “essentially composed” of a compound A when the powder comprises at least 98% by mass, preferably at least 99% by mass of the compound A, relative to the total mass of the powder.
• Metal powder comprising a NiCr alloy
• the metal powder 4 is essentially composed of an alloy of nickel and chromium (called nickel-chromium alloy and denoted NiCr).
• NiCr nickel-chromium alloy
• the matrix powder comprises at least 99% by mass of NiCr.
• the other component may for example comprise at least one of the following elements: carbon, silicon, manganese, oxygen, nitrogen. This makes it possible to obtain a coating 6 comprising NiCr which gives the mold 1 thermomechanical protection.
• a coating 6 comprising NiCr gives the mold 1 better abrasion resistance, which is particularly useful in the case of molds for borosilicate glasses and in the case of molds made of a copper and tin alloy.
• borosilicate glasses are particularly abrasive and generally lead to premature wear of the molds.
• copper and tin alloy molds they have good thermal conductivity and are usually very expensive, so it is advantageous to lose some of the thermal conductivity of the mold if it allows it to be preserved longer.
• the glassware mold 1 is a mold for borosilicate glass or a mold made of a copper and tin alloy, for example bronze.
• the nickel content in the NiCr alloy is advantageously between 40% and 85% by mass, preferably between 45 and 80% by mass, relative to the total mass of the NiCr alloy, the remainder being essentially made up of chromium.
• the nickel content in the NiCr alloy is between 40 and 50% by mass, while the chromium content is between 50% and 60% by mass, relative to the total mass of the NiCr alloy (i.e. the balance necessary to reach essentially 100% of the mass of the NiCr alloy).
• the nickel content in the NiCr alloy is substantially equal to 50% by mass, the chromium content also being substantially equal to 50% by mass, relative to the total mass of the NiCr alloy (i.e. the balance necessary to reach essentially 100% of the mass of the NiCr alloy).
• the nickel content in the NiCr alloy is about 80% by mass, while the chromium content is about 20% by mass, relative to the total mass of the NiCr alloy (i.e. the balance necessary to reach essentially 100% of the NiCr alloy mass).
• the particle size of the NiCr powder is advantageously between 10 and 50 pm.
• the D50 value of the NiCr powder is typically between 20 and 30 pm, preferably between 25 and 27 pm, for example substantially equal to 26.1 pm.
• the D10 value of the NiCr powder is typically between 10 and 20 pm, preferably between 14 and 16 pm, for example substantially equal to 14.7 pm.
• the D90 value of the NiCr powder is typically between 40 and 50 pm, preferably between 43 and 45 pm, for example substantially equal to 44.0 pm.
• the tapped density of NiCr powder is typically between 4 and 5 g/cm 3 , in particular between 4.3 and 4.8 g/cm 3 , for example of the order of 4.7 g/cm 3 .
• the true density of NiCr powder is typically between 7.5 and 8.5 g/cm 3 , in particular between 7.6 and 8.0 g/cm 3 , for example of the order of 7.71 g/cm 3 .
• the metal powder 4 comprises or is essentially composed of an alloy of copper, nickel, aluminum and zinc, which for the sake of simplification will be called “cupronickel” in the following or CuNiAIZn.
• a coating 6 comprising an alloy called “cupronickel” which gives the mold better thermal conductivity, which makes it possible to cool the glass more homogeneously during contact with the coated mold.
• Such a coating is particularly advantageous in the case of molds for soda-lime glasses.
• the glassware mold 1 is a mold for soda-lime glasses.
• the material of the mold 1 is typically a cast iron, for example a graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, an iron-carbon steel, a refractory steel or a stainless steel.
• the metal powder 4 is essentially made up of a powder of an alloy comprising, by mass relative to the total mass of the alloy:
• the possible complement preferably being essentially composed of chromium, manganese and/or iron; it being understood that the sum of the components is equal to 100%.
• the matrix powder comprises at least 97%, preferably at least 99%, of copper, nickel, aluminum and zinc.
• the other component represents at most 3% by mass, preferably at most 1% by mass, relative to the total mass of the alloy.
• the other component may comprise, by mass relative to the total mass of the alloy:
• the “cupronickel” matrix powder may comprise (relative to the total mass of the matrix powder):
• the tapped density of “cupronickel” powder is typically between 1 and 6 g/cm 3 , especially between 4.5 and 5.5 g/cm 3 .
• the true density of “cupronickel” powder is typically between 4 and 9 g/cm 3 , especially between 7.5 and 9.0 g/cm 3 .
• the particle size of the “cupronickel” powder is advantageously between 15 and 45 pm.
• the D50 value of the “cupronickel” powder is typically between 20 and 30 pm.
• Metal powder 4 is obtained by mixing a NiCr matrix powder with a TiO2 lubricating powder, in the following proportions: - 95% by mass of NiCr powder comprising 50% by mass of nickel and 50% by mass of chromium (i.e., in the total powder, 47.5% by mass of nickel and 47.5% by mass of chromium); and
• NiCr powder used is made up of an alloy comprising approximately 50% by mass of Nickel and approximately 50% by mass of Chromium. It is marketed by SANDVIK OSPREY.
• the melting temperature of the NiCr compound is 1345 °C.
• the NiCr powder comprises at least 75% by mass, advantageously at least 80% by mass of spherical grains, relative to the total weight of the NiCr powder.
• the average value of the tapped density after three measurements is 4.7 g/ cm3 .
• the powder test portion for true density measurement was 30.8561 g.
• the mean true density value after five measurements was 7.71 g/cm 3 with a standard deviation of 0.001.
• TiC>2 powder used is marketed by Saint Gobain, under the name “TiC>2 anastase nanostructured powder”.
• the TiC>2 powder comprises at least 95% by weight, advantageously at least 98% by weight of spherical grains, relative to the total weight of the TiC>2 powder.
• the surface appearance of the grains is very smooth.
• At least 80% by weight of the grains have internal porosities, relative to the total weight of the TiC>2 powder.
• the average value of the packed density after three measurements is 1.2 g/ cm3 .
• the true density was measured under the same conditions as for the NiCr compound, with a powder test portion of 7.3359 g.
• the mean value of the true density after five measurements was 4.16 g/cm 3 with a standard deviation of 0.002.
• Each plate has a free surface representative of the metal surface of the metal part, for example the molding surface 2 of a glass mold 1, intended to receive a drop of glass.
• the five plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.
• Each plate has its free surface covered with a coating obtained according to the method 100 of the present disclosure
• Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the method 100 of the present disclosure, with the following parameters:
• Laval type ceramic spray nozzle 7 (convergent-divergent) with an outlet diameter of 6 mm; powder flow rate: 2.89 cm 3 /min; spray gas 3: nitrogen; spray gas flow rate: 4 m 3 /h; cooling fluid: distilled water; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above in example 1, at room temperature (20°C); and number of passes: 10
• Thickness j Deposit plate j (mm) 0.84 0.60 0159 0.72 1.02 Plate 5 has an optimum thickness. The deposition efficiency of plate 1 is also satisfactory.
• the porosity of the coatings was evaluated by making a slice of the coating.
• Comparison of plates 3 and 4 shows equivalent efficiency and similar porosity by increasing the pressure and temperature parameters (40 bar - 900°C to 50 bar - 1000°C).
• Plate 3 was made with a scanning pitch of 2 mm and a speed of 200 mm/s while the coating of plate 1 was made with a pitch of 1 mm and a speed of 400 mm/s.
• reducing the pitch and increasing the projection speed allows to increase the deposited thickness and to decrease the porosity (evaluated by image analysis at 1.0% ⁇ 0.5 for plate 1 against 2.3% ⁇ 0.3 for plate 3).
• the comparison of plates 1 and 5 demonstrates a gain in efficiency (ratio between the mass of the coating obtained and the mass of powder projected on the plate) by increasing the temperature of the projection gas from 1000°C (plate 1) to 1100°C (plate 2).
• the efficiency (%DE, acronym for deposition efficiency) of plates 1 and 5 is 52% and 68% respectively.
• the projection distance is optimized at 20 mm because we observe a slight reduction in the thickness deposited on plates 3 and 2 (20 mm and 35 mm).
• Plate 5 leads to the thickest coating and especially a very good compactness of the coating which displays very little porosities.
• the quantification of the porosity rate by image analysis evaluates the porosity rate of the coating of plate 5 at 0.3% ⁇ 0.05 and that of plate 3 at 2.3 ⁇ 0.3.
• the following table gives the porosity size indices (area equivalent diameters) of the coatings of plates 3 and 5 calculated by image analysis.
• the minimum size of the porosities considered is 0.99 pm 2 .
• the median size (area equivalent) of the porosity is three times smaller in the coating of plate 5 than in the coating of plate 3. Note that these porosity size values are satisfactory for application to glassware molds.
• the binding rate of the coating of plate 3 is evaluated by image analysis at 83.7% and that of plate 5 at 98.4% demonstrating the excellent performance of the parameterization of plate 5.
• the coating of plate 5 is optimal in terms of thickness, porosity, yield and bonding rate.
• the roughness of coating 5 is equal to 7.0 pm (measured with a Mitutoty SJ210 roughness meter).
• the optimized projection parameters are as follows:
• Metal powder 4 is obtained by mixing a matrix powder of NiCr with a lubricating powder of TiC>2, in the following proportions:
• NiCr powder comprising 78.7% by mass of nickel ( ⁇ 0.6%) and 20.10% by mass of chromium ( ⁇ 0.05%) (i.e., in the total powder, 39.35% by mass of nickel and 10.1% by mass of chromium);
• NiCr powder used is Metco 43VF-NS powder marketed by SANDVIK OSPREY.
• NiCr powder consists of irregularly shaped particles.
• the average value of the tapped density after three measurements is 4.6 g/ cm3 .
• the average true density value after five measurements was 8.30 g/cm 3 .
• the TiC>2 powder is identical to that used in example 1.
• the seven plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.
• Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the method 100 of the present disclosure, with the following parameters: Distance Pressure Temperature Speed
• Laval type ceramic spray nozzle 7 (convergent-divergent) with an outlet diameter of 6 mm; powder flow rate: 2.45 cm 3 /min; spray gas 3: nitrogen; spray gas flow rate: 4 m 3 /h; cooling fluid: distilled water; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above in example 2, at room temperature (20°C); and number of passes: 10
• the effectiveness of the cold spray parameters is evaluated by measuring the thickness of the deposits obtained:
• the coating of plates 1, 5 and 7 has an optimal thickness.
• the coatings were obtained with a pitch of 1 mm and a speed of 400 mm/s. This pair of projection pitch and scanning speed parameters are therefore relevant.
• the yield obtained is satisfactory for all plates (88% for plate 5 and 65% for plate 2 for example).
• the yield of plate 1 is calculated at 80%.
• the porosity of the coatings was evaluated by making a slice of the coating.
• the coatings have a very good metallurgical quality, with a porosity rate between 1.5% and 4%.
• the porosity of the coatings was evaluated by making a slice of the coating.
• the coatings of plates 1 to 6 have a very good metallurgical quality, with a porosity rate between 1.5% and 3%.
• the bonding rate of the coatings is higher than 95% for each plate.
• the coating of plate 7 has a lower bonding rate and a higher porosity rate which translate into a lower metallurgical quality: this is due to the low temperature and pressure values of the projection gas (800 °C and 40 bar).
• the following table gives the porosity size indices (area equivalent diameters) of the coatings of plates 1 and 7 calculated by image analysis.
• the minimum size of the porosities considered is 0.99 pm 2 .
• the coating of plate 1 is optimal in terms of thickness, porosity, yield and bonding rate.
• the roughness of coating 1 is equal to 6.5 pm (measured with a Mitutoty SJ210 roughness meter).
• Metal powder 4 is obtained by mixing a cupronickel type matrix powder with a TiC>2 lubricating powder, in the following proportions:
• Cupronickel powder used is marketed by NANOVAL.
• the exact composition of the powder is given below:
• the melting temperature of the powder is 1235°C.
• Cupronickel powder consists of spherical particles, except for a few clusters that are very irregular. The grains do not have many satellites.
• the average value of the tapped density after three measurements is 4.6 g/ cm3 .
• the average true density value after five measurements was 7.44 g/ cm3 .
• the TiC>2 powder is identical to that used in example 1.
• the eight plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.
• Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the method 100 of the present disclosure, with the following parameters:
• Laval type ceramic spray nozzle 7 (convergent-divergent) with an outlet diameter of 6 mm; powder flow rate: 2.5 cm 3 /min; spray gas 3: nitrogen; spray gas flow rate: 4 m 3 /h; cooling fluid: distilled water; metal powder 4: consisting of cupronickel and titanium dioxide, as described above in example 3, at room temperature (20°C); and number of passes: 10
• the coating of plates 1 to 3 is too thin, which shows that the temperature of the projection gas must be at least 800°C.
• the efficiency gain is also very significant when the projection temperature increases from 800°C to 900°C.
• the efficiency is then stable for projection temperatures greater than or equal to 900°C.
• the porosity of the coatings was evaluated by making a slice of the coating.
• the coatings have a very good metallurgical quality, with a porosity rate between 0.3% and 2%.
• the porosity rate of the coating of plate 7 is for example 0.3%, that of plates 5 and 8 1.4% and 1.0% respectively.
• the porosity of the coatings was evaluated by making a slice of the coating.
• the coatings of plates 1 to 6 have a very good metallurgical quality, with a porosity rate between 1.5% and 3%.
• the following table gives the porosity size indices (area equivalent diameters) of the coatings of plates 1 and 7 calculated by image analysis.
• the minimum size of the porosities considered is 0.99 pm 2 .
• the binding rate of plates 5 and 7 is 72% and 88% respectively, which is very good.
• the coating of plate 7 is optimal in terms of thickness, porosity, yield and bonding rate.
• the roughness of coating 7 is equal to 7.6 pm (measured with a Mitutoty SJ210 roughness meter).

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