Abstract: High compressibility iron powder that is suitably used for parts with excellent magnetic characteristics or high density sintered parts and that has good productivity is provided from pure iron powder which includes, as impurities in percent by mass, C: 0.005% or less, Si: more than 0.01% and 0.03% or less, Mn: 0.03% or more and 0.07% or less, P: 0.01% or less, S: 0.01% or less, O: 0.10% or less, and N: 0.001% or less, and whose particle includes four or less crystal grains on average and has a micro Vickers hardness (Hv) of 80 or less on average. The circularity of the iron powder is preferably 0.7 or more.

Abstract: It is an object to provide an inexpensive alloy for heat dissipation having a small thermal expansion coefficient as known composite materials, a large thermal conductivity as pure copper, and excellent machinability and a method for manufacturing the alloy. In particular, since various shapes are required of the alloy for heat dissipation, a manufacturing method by using a powder metallurgy method capable of supplying alloys for heat dissipation, the manufacturing costs of which are low and which take on various shapes, is provided besides the known melting method. The alloy according to the present invention is a Cu—Cr alloy, which is composed of 0.3 percent by mass or more, and 80 percent by mass or less of Cr and the remainder of Cu and incidental impurities and which has a structure in which particulate Cr phases having a major axis of 100 nm or less and an aspect ratio of less than 10 are precipitated at a density of 20 particles/?m2 in a Cu matrix except Cr phases of more than 100 nm.

Abstract: To provide an iron-based sintered alloy excellent in shape accuracy and wear resistance, and reduced hostility to mating materials, and having sufficient hardness after tempering, as well as a manufacturing method thereof. Iron-based alloy powder of a composition comprising Cr: from 1 to 3.5 mass %, Mo: from 0.2 to 0.9 mass %, V: from 0.1 to 0.5 mass % and the balance of Fe and impurities, and carbon powder are mixed at a ratio of the carbon powder based on the entire portion within a range from 0.8 to 1.1 mass %, the mixture is compacted, the compacted body is sintered and quenching is applied to the sintered body heated again after once lowering temperature of the sintered body. This can provide an iron-based sintered alloy where fine M7C3 carbides are dispersed in martensitic texture.

Abstract: In a Cr—Cu alloy that is formed by powder metallurgy and contains a Cu matrix and flattened Cr phases, the Cr content in the Cr—Cu alloy is more than 30% to 80% or less by mass, and the average aspect ratio of the flattened Cr phases is more than 1.0 and less than 100. The Cr—Cu alloy has a small thermal expansion coefficient in in-plane directions, a high thermal conductivity, and excellent processability. A method for producing the Cr—Cu alloy is also provided. A heat-release plate for semiconductors and a heat-release component for semiconductors, each utilizing the Cr—Cu alloy, are also provided.

Abstract: An iron-based compact having a high density and also an iron-based sintered body having a high strength and a high density are manufactured with a high productivity by pre-compacting an iron-based mixed powder prepared by mixing an iron-based metal powder and a graphite powder; pre-sintering the resulting pre-compacted iron-based mixed powder at a temperature higher than 1000° C. but not higher than 1300° C. to produce a sintered iron-based powder preform containing C: 0.10 to 0.50 mass %, O: 0.3 mass % or less, and N: 0.010 mass % or less and having a density of 7.2 Mg/m3 or more; and subjecting the sintered iron-based powder preform to high-velocity compaction at a compaction energy density of 1.8 MJ/m2 or more (1.4 MJ/m2 or more for a sintered pure-iron based powder preform).

Abstract: Mo of 0.05 to 1.0% by mass is adhered to the surfaces of an iron-based powder containing Mn of 0.5% by mass or less and Mo of 0.2 to 1.5% by mass as prealloyed elements by diffusion bonding, whereby an alloy steel powder is formed. Furthermore, a Ni powder of 0.2 to 5% by mass and/or a Cu powder of 0.2 to 3% by mass are added to the alloy steel powder, whereby a mixed powder for powder metallurgy is formed. The mixed powder for powder metallurgy according to the present invention enables production of sintered bodies having high density as well as superior tensile strength and rotating bending fatigue strength.

Abstract: An alloy steel powder for powder metallurgy includes an iron-based powder containing about 0.5 mass percent or less of Mn as a prealloyed element and 0.2 to about 1.5 mass percent of Mo as a prealloyed element; and a Mo-containing alloy powder bonded on the surface of the iron-based powder by diffusion bonding. In the alloy steel powder for powder metallurgy, a Mo average content [Mo]T (mass percent) satisfies formula 0.8?[Mo]T?[Mo]P?0.05, wherein the content [Mo]P is the above prealloyed Mo content (mass percent) in the iron-based powder.

Abstract: An iron-based mixed powder for powder metallurgy having improved machinability, without degrading the mechanical property of a sintered body made by compacting the iron-based mixed power. The iron-based mixed powder comprises a mixture of an iron-based powder, a powder for an alloy, a powder for machinability improvement, and a lubricant. The powder for machinability improvement comprises a manganese sulfide powder, and at least one selected from the group consisting of a calcium phosphate powder and a hydroxy apatite powder. Alternatively the powder for machinability improvement has an average particle diameter of 1 to 60 micrometers and comprise manganese sulfide powder and calcium fluoride powder.

Abstract: To provide an iron-based sintered alloy excellent in shape accuracy and wear resistance, and reduced hostility to mating materials, and having sufficient hardness after tempering, as well as a manufacturing method thereof. Iron-based alloy powder of a composition comprising Cr: from 1 to 3.5 mass %, Mo: from 0.2 to 0.9 mass %, V: from 0.1 to 0.5 mass % and the balance of Fe and impurities, and carbon powder are mixed at a ratio of the carbon powder based on the entire portion within a range from 0.8 to 1.1 mass %, the mixture is compacted, the compacted body is sintered and quenching is applied to the sintered body heated again after once lowering temperature of the sintered body. This can provide an iron-based sintered alloy where fine M7C3 carbides are dispersed in martensitic texture.

Abstract: Mo of 0.05 to 1.0% by mass is adhered to the surfaces of an iron-based powder containing Mn of 0.5% by mass or less and Mo of 0.2 to 1.5% by mass as prealloyed elements by diffusion bonding, whereby an alloy steel powder is formed. Furthermore, a Ni powder of 0.2 to 5% by mass and/or a Cu powder of 0.2 to 3% by mass are added to the alloy steel powder, whereby a mixed powder for powder metallurgy is formed. The mixed powder for powder metallurgy according to the present invention enables production of sintered bodies having high density as well as superior tensile strength and rotating bending fatigue strength.

Abstract: The invention provides an iron-based mixed powder for powder metallurgy enabling the iron-based mixed powder to improve the machinability, without being accompanied by degrading the mechanical property of a sintered body. In order to obtain the purpose of the invention, the iron-based mixed powder comprises a mixture of an iron-based powder, a powder for an alloy, a powder for machinability improvement, while further adding lubricant. And, (1) the powder for machinability improvement comprises a manganese sulfide powder, and at least one selected from the group consisting of a calcium phosphate powder and a hydroxy apatite powder, or, (2) the powder for machinability improvement has an average particle diameter of 1 to 60 micrometers and is at least one selected from the group consisting of manganese sulfide powder and calcium fluoride powder.

Abstract: A method for manufacturing sponge iron includes heating iron oxide together with a solid reducing agent to reduce the iron oxide into sponge iron, wherein the iron oxide includes a mixture of powdered hematite and powdered iron ore or a mixture of powdered hematite and powdered mill scale, the powdered hematite has a specific surface area of 2.0 m2/g or more, and the content of the powdered hematite is 5-45% by mass with respect to the total quantity of iron oxide.

Abstract: In a preliminary molding step 1, a metallic powder mixture 7 obtained by blending an iron-based metal powder 7a with graphite 7b such that the graphite is present in an amount of preferably not less than 0.1% by weight, more preferably not less than 0.3% by weight, is compacted into a preform 8 having a density of not less than 7.3 g/cm3. In a provisional sintering step 2, the preform 8 is provisionally sintered at a predetermined temperature to form a metallic powder-molded body 9 having a structure in which the graphite remains along a grain boundary of the metal powder. In a re-compaction step 3, the metallic powder-molded body 9 is re-compacted into a re-compacted body 10. In a re-sintering step 4, the re-compacted body 10 is re-sintered to obtain a sintered body 11. In a heat treatment step 5, the sintered body 11 is heat-treated to obtain a heat-treated sintered body 11.

Abstract: A manufacturing method for high-density iron-based powder compacts is disclosed. The temperature of the die is adjusted at ordinary temperature or at a predetermined temperature by preheating. A lubricant for die lubrication prepared by mixing at least two different lubricants having melting points higher than a predetermined temperature of the compaction pressure is sprayed at the upper part of the die and is introduced into the die and adhered by electrification to the surface of the die. The resulting die is filled with an iron-based mixed powder including a lubricant and molding is performed at ordinary temperature or at a temperature raised by heating.

Abstract: The surface of the body of powder additive for use in powder metallurgy is coated with an organic binder, thereby obtaining powder additive to cause adhesion of the powder additive to the surface of iron-based powder by the organic binder, thereby providing a powder additive with no segregation of components and excellent flowability and compression, and an iron-based powder mixture manufactured by mixing the powder additive and the iron-based powder.

Abstract: An alloy steel powder for powder metallurgy includes an iron-based powder containing about 0.5 mass percent or less of Mn as a prealloyed element and 0.2 to about 1.5 mass percent of Mo as a prealloyed element; and a Mo-containing alloy powder bonded on the surface of the iron-based powder by diffusion bonding. In the alloy steel powder for powder metallurgy, a Mo average content [MO]T (mass percent) satisfies formula 0.8?[M]T—[Mo]P?0.05, wherein the content [Mo]P is the above prealloyed Mo content (mass percent) in the iron-based powder.

Abstract: A magnetite-iron based composite powder includes magnetite with a ratio of X-ray diffraction intensity to that of &agr;-Fe of about 0.001 to about 50 and has an average primary particle size of about 0.1 to about 10 &mgr;m. The composite powder can highly dehalogenate organic halogen compounds and exhibits satisfactory absorption power of high frequency electromagnetic waves after molding. An ultrafine nonferrous inorganic compound powder may adhere to the surface of the composite powder, or at least the composite powder may adhere to the surfaces of small particles of a nonferrous inorganic compound to thereby yield a composite powder composition. The composite powder can be produced by partial reduction of a material powder containing a hematite based powder or by complete reduction and subsequent partial oxidation of the material powder.

Abstract: A magnetite-iron based composite powder includes magnetite with a ratio of X-ray diffraction intensity to that of &agr;-Fe of about 0.001 to about 50 and has an average primary particle size of about 0.1 to about 10 &mgr;m. The composite powder can highly dehalogenate organic halogen compounds and exhibits satisfactory absorption power of high frequency electromagnetic waves after molding. An ultrafine nonferrous inorganic compound powder may adhere to the surface of the composite powder, or at least the composite powder may adhere to the surfaces of small particles of a nonferrous inorganic compound to thereby yield a composite powder composition. The composite powder can be produced by partial reduction of a material powder containing a hematite based powder or by complete reduction and subsequent partial oxidation of the material powder.

Abstract: A sintered body is produced by preparing a metal powder mixture, compacting the metal powder mixture to provide a green compact and then sintering the green compact. The metal powder mixture includes a fine metal powder having a particle size of 75 &mgr;m or smaller, a graphite powder in an amount of 0.1 to 1.0% by mass and a powder lubricant in an amount of 0.05 to 0.80% by mass based on a total mass of the metal powder mixture.

Abstract: A Mo source powder is added to and mixed with an iron-based powder containing 1.0% by mass or less of prealloyed Mn to yield a powder mixture containing 0.2 to 10.0% by mass of Mo, the resulting powder mixture is subjected to heat treatment in a reducing atmosphere to thereby yield an alloyed steel powder containing Mo as a powder partially diffused and bonded to a surface of the iron-based powder particles. The prepared alloyed steel powder for powder metallurgy has satisfactory compactability. The use of this alloyed steel powder can produce a sintered powder metal body (an intermediate material after compaction and preliminary sintering in re-compaction of sintered powder materials process) for highly strong sintered member.