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
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/64—Burning or sintering processes
  • C04B35/65—Reaction sintering of free metal- or free silicon-containing compositions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/14—Treatment of metallic powder
  • B22F1/145—Chemical treatment, e.g. passivation or decarburisation
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
  • C01B21/0615—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with transition metals other than titanium, zirconium or hafnium
  • C01B21/0622—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with transition metals other than titanium, zirconium or hafnium with iron, cobalt or nickel
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/082—Compounds containing nitrogen and non-metals and optionally metals
  • C01B21/0828—Carbonitrides or oxycarbonitrides of metals, boron or silicon
• • 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
  • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
  • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
  • C04B35/58042—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on iron group metals nitrides
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
  • C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
  • C22C29/04—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbonitrides

Definitions

• the present invention relates to an iron-nitride-carbide powder which is especially suited for use in the production of sintered iron bodies of good strength and high resistance to wear, as well as of good conductivity.
• an iron-nitride-carbide powder with a maximum nitrogen content of 7%, preferably 46%, a carbon content of 1-3%, preferably 1.82%, and containing the nitrogen essentially or entirely in the E-iron nitride phase is admirably suited for purposes indicated above.
• a further important requirement for the effective use of the iron nitride powder according to the invention for improving the mechanical properties and the sintering properties of iron/iron-nitride-carbide powder mixtures is that the nitrided component is practically free of when.
• iron-nitride-carbide powders having a 4 to 6% nitrogen content. It was previously not known that iron nitrogen alloys could be prepared with such a low nitrogen content, wherein the nitrogen content is only in the f-phase and whose X-ray picture show neither an a-iron phase nor a 'y-phase. Preferably the ratio of carbon to nitrogen is about 1:3.
• the ironnitride-carbide powder according to the invention can be produced by nitriding in fused cyanate containing salt baths.
• acyanate' as the nitriding salt in the production of the iron-nitridecarbide powders according ot-the invention as then the solutions obtained upon washing the treated iron powders are not poisonous or at least considerably less poisonous than the solutions which are obtained when cyanide cyanate mixtures are used.
• cyanate when cyanate is used alone the nitriding can be effected in a considerably shorter time, for example, in about 15 minutes.
• the nitriding of a mixture of iron powder and cyanate provides an extraordinarily good assurance of providing the desired nitrogen and carbon contents, the freedom from a-phase and that the nitrogen content is practically quantitatively only in the g-iron nitride phase.
• the nitrogen content can be adjusted by changing the cyanide cyanate ratio. Pure cyanate, for example, will provide a nitrogen content of about 5.5% by weight with a nitriding time of 15-30 minutes. A mixture of cyanate and 15% cyanide provides a nitrogen content of about 4.5% with the same carbon content with a nitriding time of about 2-3 hours.
• Example 1 6 kg. of iron powder with an average grain size of 40 60 were carefully mixed with 7 kg. of a salt mixture of 15% of sodium cyanide and 85% of potassium cyanate and such mixture heated in an iron crucible in an electric furnace for 2.5 hours at 570 C. After cooling down the resulting salt cake was treated with water until all of the salt was washed out. 6.4 kg. of nitrided iron powder with a nitrogen content of 4.5% and a carbon content of 1.8% were obtained. Upon X-ray analysis only s-iron nitride and no a-iron could be ascertained.
• Example 2 7 kg. of iron powder with an average grain size of 40-60 were carefully mixed with 7 kilograms of pota sium cyanate and such mixture heated in an iron crucible for 30 minutes at 570 C. in an electric furnace. After cooling down the resulting salt cake was treated with water until all of the salt was washed out. 7.5 kg. of nitrided iron powder with a nitrogen content of 5.5% and a carbon content of 1.9% were obtained. Upon X-ray analysis again only .i-iron nitride and no ct-ilOtl could be ascertained.
• Iron-nitride-carbide powder the individual particles of which have a carbon content of 1-3% by weight and a maximum nitrogen content of 7% by weight, said ironnitride-carbide powder being free of a-rion and having the nitrogen content essentially only in the E-iron nitride phase.
• Iron-nitride-carbide powder the individual particles of which have a carbon content of 1.82% by weight and a nitrogen content of 46% by weight, said iron-nitridecarbide powder being free of a wiron and having the nitrogen content essentially only in the g-iron nitride phase. 7 1

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Ceramic Engineering (AREA)
• Inorganic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Crystallography & Structural Chemistry (AREA)
• Ceramic Products (AREA)
• Compounds Of Iron (AREA)

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Citations (4)

• 1962
  • 1962-02-13 DE DED38140A patent/DE1178219B/de active Pending
• 1963
  • 1963-01-10 CH CH24463A patent/CH438754A/de unknown
  • 1963-02-08 GB GB5274/63A patent/GB992435A/en not_active Expired
  • 1963-02-08 US US257086A patent/US3145458A/en not_active Expired - Lifetime

Patent Citations (4)

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