Abstract: A process for producing aluminum nitride includes a nitrogen occluding step and a nitriding step. In the nitrogen occluding step, nitrogen is occluded in an aluminum powder having an average particle diameter of from 10 to 200 ?m by holding the aluminum powder in a nitrogen gas atmosphere of 460° C. or more for 10 minutes or more. In the nitriding step, the aluminum powder with nitrogen occluded therein is nitrided by developing a nitriding reaction at a temperature of from 500 to 1,000° C. while holding the aluminum powder in a nitrogen atmosphere whose nitrogen gas pressure falls in a range of from 80 to 300 kpa. Thus, aluminum nitride, in which aluminum is inhibited from remaining and which has small particle diameters, is calcined at a lower temperature and is actively used to make high-quality substrates, can be produced at a lower temperature with a high yield.

Abstract: A process for producing aluminum nitride includes a step of holding an aluminum powder in a nitrogen atmosphere whose nitrogen gas pressure falls in a range of from 105 to 300 kPa, thereby developing a nitriding reaction at a temperature of from 500 to 1,000° C., wherein a reaction controller gas, controlling the development of the nitriding reaction, is supplied into a reactor chamber in which the aluminum powder is accommodated. In the production process, the reaction controller gas is included in the nitrogen atmosphere in the development of the nitriding reaction. Accordingly, the development of the nitriding reaction is controlled so that it is possible to develop the nitriding reaction at a lower temperature. As a result, it is possible to produce an aluminum nitride powder whose particle diameters are fine.

Abstract: A process for producing aluminum nitride includes a nitrogen occluding step and a nitriding step. In the nitrogen occluding step, nitrogen is occluded in an aluminum powder having an average particle diameter of from 10 to 200 &mgr;m by holding the aluminum powder in a nitrogen gas atmosphere of 460° C. or more for 10 minutes or more. In the nitriding step, the aluminum powder with nitrogen occluded therein is nitrided by developing a nitriding reaction at a temperature of from 500 to 1,000° C. while holding the aluminum powder in a nitrogen atmosphere whose nitrogen gas pressure falls in a range of from 80 to 300 kpa. thus, aluminum nitride, in which aluminum is inhibited from remaining and which has small particle diameters, is calcined at a lower temperature and is actively used to make high-quality substrates, can be produced at a lower temperature with a high yield.

Abstract: A process for producing aluminum nitride includes a step of holding an aluminum powder in a nitrogen atmosphere whose nitrogen gas pressure falls in a range of from 105 to 300 kPa, thereby developing a nitriding reaction at a temperature of from 500 to 1,000° C., wherein a reaction controller gas, controlling the development of the nitriding reaction, is supplied into a reactor chamber in which the aluminum powder is accommodated. In the production process, the reaction controller gas is included in the nitrogen atmosphere in the development of the nitriding reaction. Accordingly, the development of the nitriding reaction is controlled so that it is possible to develop the nitriding reaction at a lower temperature. As a result, it is possible to produce an aluminum nitride powder whose particle diameters are fine.

Abstract: A process for producing aluminum nitride comprises a step of nitriding directly a mixed powder comprising of, a bulky aluminum powder composed of aluminum or an aluminum alloy powder which occupies 50 to 97% by weight and whose sieve opening of JIS is not less than 210 .mu.m (70 mesh); and a nitriding accelerator powder composed of at least one kind of an aluminum powder and an aluminum alloy powder which occupy the balance of 50 to 3% by weight and whose sieve opening is less than 210 .mu.m (70 mesh); under a nitrogen gas atmosphere of the temperature ranging from 500 to 1000.degree. C. In the present invention, there can be obtained an aluminum nitride which is easy to be crushed by hand by using a mortar.

Abstract: This invention aims to provide a nitriding method of forming a relatively thick nitride layer on the surface of an aluminum material containing silicon, and an auxiliary agent for nitriding. By using a nitriding auxiliary agent mainly comprising aluminum containing a metal such as lithium or boron, which has a high bonding strength with oxygen, coexists with silicon to form substantially no silicide, or a nitriding auxiliary agent mainly comprising an Al--Mg--Cu alloy or an Mg--Zn--Cu alloy, heat treatment is applied by nitrogen gas with the aluminum material to be nitrided contacted with the nitriding auxiliary agent. Hence, a thick nitride layer can be easily formed even on the surface of an aluminum material containing silicon, and this is most suitable to surface nitride aluminum-silicon alloys, which possess superior castability.

Abstract: An aluminum product having the metal diffusion layer in the present invention has, on the surface thereof, a metal diffusion layer comprising aluminum and a diffusion metal which is diffused setting aluminum as a matrix and which includes at least one selected from the group consisting of Ni, Cr, Cu, Zn, Mg, Ti and Ag; wherein the diffusion layer is formed by diffusing inclinatorily not less than 1 .mu.m from the surface thereof; and the diffusion metal is not less than 1.0% by weight when the whole of the metal diffusion layer is set to be 100% by weight. Also, in a process for producing an aluminum product having a metal diffusion layer, the surface of the aluminum product is brought into contact with the processing agent including at least the diffusion metal powder; and in this state by conducting heat treatment in the atmosphere including nitrogen, the diffusion metal is diffused on the surface of the aluminum product and the metal diffusion layer is formed.

Abstract: A case nitrided aluminum product is produced by contacting an aluminum product with a nitriding agent at a part of a surface thereof at least, and by nitriding the aluminum product at the surface with an ambient gas at a temperature of a melting point of the aluminum product or less while keeping the aforementioned contact. The nitriding agent includes an aluminum powder, and the ambient gas virtually includes a nitrogen gas. The resulting nitriding layer has a depth of 5 micrometers or more, and it exhibits a case hardness of from 250 to 1,200 mHv. Thus, it is possible to form the deep and hard nitriding layer on the aluminum product with ease under the conditions where it has been said to be too difficult to nitride aluminum products. The case nitrided aluminum product can appropriately make sliding parts which require high wear resistance.

Abstract: A high heat resisting and high abrasion resisting aluminum alloy and aluminum alloy powder have superior toughness, abrasion resistance, high temperature strength, and creep resistance and are useful to form engine parts for automobiles, airplanes, etc. The high heat resisting and high abrasion resisting aluminum alloy comprises 2 to 15 wt % of Ni, 0.2 to 15 wt % of Si, 0.6 to 8.0 wt % of Fe, one or two of 0.6 to 5.0 wt % of Cu and 0.5 to 3 wt % of Mg, the total amount of Cu and Mg being equal to or less than 6 wt %, one or two of 0.3 to 3 wt % of Zr and 0.3 to 3 wt % of Mo, the total amount of Zr and Mo being equal to or less than 4 wt %, 0.05 to 10 wt % of B, and the balance of Al and unavoidable impurities, and is produced by powder metallurgy.

Abstract: A case nitrided aluminum product is produced by contacting an aluminum product with a nitriding agent at a part of a surface thereof at least, and by nitriding the aluminum product at the surface with an ambient gas at a temperature of a melting point of the aluminum product or less while keeping the aforementioned contact. The nitriding agent includes an aluminum powder, and the ambient gas virtually includes a nitrogen gas. The resulting nitriding layer has a depth of 5 micrometers or more, and it exhibits a case hardness of from 250 to 1,200 mHv. Thus, it is possible to form the deep and hard nitriding layer on the aluminum product with ease under the conditions where it has been said to be too difficult to nitride aluminum products. The case nitrided aluminum product can appropriately make sliding parts which require high wear resistance.

Abstract: A case nitrided aluminum product is produced by contacting an aluminum product with a nitriding agent at a part of a surface thereof at least, and by nitriding the aluminum product at the surface with an ambient gas at a temperature of a melting point of the aluminum product or less while keeping the aforementioned contact. The nitriding agent includes an aluminum powder, and the ambient gas virtually includes a nitrogen gas. The resulting nitriding layer has a depth of 5 micrometers or more, and it exhibits a case hardness of from 250 to 1,200 mHv. Thus, it is possible to form the deep and hard nitriding layer on the aluminum product with ease under the conditions where it has been said to be too difficult to nitride aluminum products. The case nitrided aluminum product can appropriately make sliding parts which require high wear resistance.

Abstract: An aluminum alloy powder for sliding members includes Fe in an amount of from 0.5 to 5.0% by weight, Cu in an amount of from 0.6 to 5.0% by weight, B in an amount of from 0.1 to 2.0% by weight and the balance of Al. An aluminum alloy includes a matrix made from the aluminum alloy powder and at least one member dispersed, with respect to whole of the matrix taken 100% by weight, in the matrix, and selected from the group consisting of B in an amount of from 0.1 to 5.0% by weight, boride in an amount of from 1.0 to 15% by weight and iron compound in an amount of from 1.0 to 15% by weight, and thereby it exhibits the tensile strength of 400 MPa or more. The aluminum alloy powder and the aluminum alloy are suitable for making sliding members like valve lifters for automobiles.

Abstract: Disclosed are heat resistant aluminum alloy powder and alloy including Ni in an amount of from 5.7 to 20% by weight, Si in an amount of from 6.0 to 25% by weight, at least one of Fe in an amount of from 0.6 to 8.0% by weight and Cu in an amount of from 0.6 to 5.0% by weight, and at least one of B in a form of the simple substance in an amount of from 0.05 to 2.0% by weight (or from 0.05 to 10% by weight for the alloy) and graphite particles (especially for the alloy) in an amount of from 0.1 to 10% by weight. The alloy powder and alloy are not only superb in the tensile strength at room temperature and high temperatures but also superior in the sliding characteristic, they can be further upgraded in the wear resistance and the fretting fatigue resistance by dispersing at least one of nitride particles, boride particles, oxide particles and carbide particles in an amount of from 0.

Abstract: An aluminum alloy consists essentially of 90 to 99.5% by weight of matrix and 0.5 to 10% by weight of a dispersant dispersed within the matrix. The matrix comprises 10 to 25% by weight of Si, 5 to 20% by weight of Ni, 1 to 5% by weight of Cu and the rest of Al and impurity elements. The dispersant is at least one selected from the group consisting of 0.5 to 10% of nitride, boride, carbide and oxide. The aluminum alloy shows excellent tensile strength and wear resistance.

Abstract: Disclosed are heat resistant aluminum alloy powders and alloys including Ni, Si, either at least one of Fe and Zr or at least one of Zr and Ti. For instance, the alloy powders or alloys consist essentially of Ni in an amount of from 5.7 to 20% by weight, Si in an amount of from 0.2 to 25% by weight, at least one of Fe in an amount of from 0.6 to 8.0% by weight and Cu in an amount of from 0.6 to 5.0% by weight, and the balance of Al. The alloy powders or alloys are optimum for a matrix of heat and wear resistant aluminum alloy-based composite materials including at least one of nitride particles and boride particles in an amount of 0. 5 to 10% by weight with respect to the whole composite material taken as 100% by weight. The alloy powders, alloys and composite materials are satisfactory applicable to the component parts of the recent automobile engines which should produce a high output.

Abstract: A method of forming a metallic composite product having a specific gravity no greater than 1.8 and a thermal expansion no greater than 16.times.10.sup.-6 .degree. C. in a preheated mold. The portion of the mold between a cavity and the gate has a stainless steel wire gauge for retaining particles. The mold is filled with screened fly ash, glass, hollow spheres having a particle size in the range of 50 to 200 micrometers and a globularness of at least 90%, which has been preheated to the same temperature as the mold. Molten aluminum alloy is injected into the mold at a pressure in the range of from 40 to 80 kgf cm.sup.2 at the gate and at a flow velocity in the range of 0.08 to 0.20 m/second.

Abstract: A carbon fiber reinforced carbon of the present invention is composed of a sintered body comprising precursor carbonaceous fiber and self-sintering carbonaceous powder with the precursor carbonaceous fiber buried therein. Since the precursor carbonaceous fiber working as a reinforcement and the self-sintering carbonaceous powder working as a binder come to have substantially the same physical properties (strength, shrinkage rate and the like), the boudary adhesion between them improves, thereby giving the sintered body high strength and excellent abrasion resistance. When the precursor carbonaceous fiber is subjected to a surface treatment using a viscous material, the wettability of the surface of the precursor carbonaceous fiber increases, thereby further improving the boundary adhesion between the precursor carbonaceous fiber and the self-sintering precursor carbonaceous powder.

Abstract: Disclosed is a sliding member having a predetermined shape and including: a sintered body obtained by sintering a composite body including: preliminary carbonized carbonaceous fiber; inorganic powder or inorganic fiber; and self-sintering carbonaceous powder with the preliminarily carbonized carbonaceous fiber and the inorganic powder or the inorganic fiber buried therein. The sliding member has a high and stable friction coefficient (.mu.), high strength, excellent abrasion resistance, and is manufacturable at a low cost. Further, the friction coefficient (.mu.) and the other properties of the sliding member can be controlled depending on an application of a sliding member by selecting an optimum inorganic powder or inorganic fiber. Particularly, when boron compound powder is selected as the inorganic powder, the friction coefficient (.mu.) of the sliding member can be suppressed to 0.15 or less, and the load at seizure thereof can be improved to 100 kgf/cm.sup.2 or more.

Abstract: A method for separating a certain metal from a raw material including a mixture of the metal and an element which has a lower vapor pressure than the metal. The raw material including the mixture of the metal and the element is heated so as to cause a first vapor including the metal to be evolved. This first vapor is passed through a throttling means in which it undergoes adiabatic expansion and is rapidly cooled so that at least part of it is reduced to a liquid containing the metal. This liquid is reheated so as to cause a second vapor including the metal to be evolved. And the second vapor is cooled to collect the metal. An apparatus is also disclosed for performing this method.

Abstract: A composite material having a high molecular weight polymer material as the matrix material and extremely fine particles of diameters of the order of tens to hundreds of angstroms dispersed in the matrix material is obtained by rapidly adiabatically cooling vapor of a metallic material through a nozzle, and squirting a jet of said fine particles into a molten mass of the high molecular weight polymer material. Optionally, inert gas may be squirted through the nozzle along with the vapor of the metallic material. Further, optionally a gas which forms a compound with the metallic material may be squirted through the nozzle with vapor of the metallic material, so that the particles become particles of a compound of the metallic material and the gas.