A powder admixture useful for making a sintered valve seat insert includes a first iron-base powder and second iron-base powder wherein the first iron-base powder has a higher hardness than the second iron-base powder, the first iron-base powder including, in weight percent, 1-2% C, 10-25% Cr, 5-20% Mo, 15-25% Co, and 30-60 wt. % Fe, and the second iron-base powder including, in weight %, 1-1.5% C, 3-15% Cr, 5-7% Mo, 3-6% W, 1-1.7% V, and 60-85% Fe. The powder admixture can be sintered to form a sintered valve seat insert optionally infiltrated with copper.

A nanocomposite metal material includes a carrier formed of Zr and two-element metal particles supported on the carrier. The two-element metal is formed of Cu and Ni, and a degree of oxidation of the carrier is more than 31% and 100% or less. In a case where the nanocomposite metal material is disposed in a reaction furnace of a thermal reactor, the inside of the reaction furnace is brought into a vacuum state, and the inside of the reaction furnace is heated to a temperature range of 250° C. or higher and 350° C. or lower with a heating mechanism included in the thermal reactor while supplying at least one of hydrogen gas and deuterium gas into the reaction furnace, excessive heat of the nanocomposite metal material is 100 W/kg or more.

A nanocomposite metal material includes a carrier formed of Zr and two-element metal particles supported on the carrier. The two-element metal is formed of Cu and Ni, and a degree of oxidation of the carrier is more than 31% and 100% or less. In a case where the nanocomposite metal material is disposed in a reaction furnace of a thermal reactor, the inside of the reaction furnace is brought into a vacuum state, and the inside of the reaction furnace is heated to a temperature range of 250° C. or higher and 350° C. or lower with a heating mechanism included in the thermal reactor while supplying at least one of hydrogen gas and deuterium gas into the reaction furnace, excessive heat of the nanocomposite metal material is 100 W/kg or more.

A method for manufacturing a sintered body, the method including heating a mixture that contains a plurality of particles of a metal oxide having a spinel-type structure, and a metal acetylacetonate under pressure at a temperature of from a melting point or higher of the metal acetylacetonate to 600° C. or lower, to form a sintered body that contains the metal oxide having the spinel-type structure.

A method for manufacturing a sintered body, the method including heating a mixture that contains a plurality of particles of a metal oxide having a spinel-type structure, and a metal acetylacetonate under pressure at a temperature of from a melting point or higher of the metal acetylacetonate to 600° C. or lower, to form a sintered body that contains the metal oxide having the spinel-type structure.

Methods for the manufacture of fine metal powders from metal carboxylate compounds such as metal oxalate compounds. The method includes decomposing particulates of the metal oxalate compound by heating to a decomposition temperature in the presence of a dilute hydrogen gas to decompose the metal oxalate compound, and forming a fine metal powder by heating to a higher refining temperature to remove contaminants from the metal powder. The method may include the conversion of a non-oxalate metal compound to a hydrated metal oxalate and the dehydration of the hydrated metal oxalate before decomposition to the metal. The method is applicable to the production of a wide variety of metals, and is particularly applicable to the production of rare earth metals of high purity and fine particle size.

Methods for the manufacture of fine metal powders from metal carboxylate compounds such as metal oxalate compounds. The method includes decomposing particulates of the metal oxalate compound by heating to a decomposition temperature in the presence of a dilute hydrogen gas to decompose the metal oxalate compound, and forming a fine metal powder by heating to a higher refining temperature to remove contaminants from the metal powder. The method may include the conversion of a non-oxalate metal compound to a hydrated metal oxalate and the dehydration of the hydrated metal oxalate before decomposition to the metal. The method is applicable to the production of a wide variety of metals, and is particularly applicable to the production of rare earth metals of high purity and fine particle size.

Processes are provided for producing a titanium alloy material, such as Ti—Al alloys. In one embodiment, the process includes: heating an input mixture to a preheat temperature with the input mixture including aluminum, optionally, AlCl.sub.3, and, optionally ally, one or more alloying element halide; introducing TiCl.sub.4 to the input mixture at the first reaction temperature such that substantially all of the Ti.sup.4+ in the TiCl.sub.4 is reduced to Ti.sup.3+; thereafter, heating to a second reaction temperature such that substantially all of the Ti.sup.3+ is reduced to Ti.sup.2+ to form an intermediate mixture (e.g., a Ti.sup.2+ salt); and introducing the intermediate mixture into a reaction chamber at a disproportionation temperature reaction to form the titanium alloy material from the Ti.sup.2+ via a disproportionation reaction.

Processes are provided for producing a titanium alloy material, such as Ti—Al alloys. In one embodiment, the process includes: heating an input mixture to a preheat temperature with the input mixture including aluminum, optionally, AlCl.sub.3, and, optionally ally, one or more alloying element halide; introducing TiCl.sub.4 to the input mixture at the first reaction temperature such that substantially all of the Ti.sup.4+ in the TiCl.sub.4 is reduced to Ti.sup.3+; thereafter, heating to a second reaction temperature such that substantially all of the Ti.sup.3+ is reduced to Ti.sup.2+ to form an intermediate mixture (e.g., a Ti.sup.2+ salt); and introducing the intermediate mixture into a reaction chamber at a disproportionation temperature reaction to form the titanium alloy material from the Ti.sup.2+ via a disproportionation reaction.

A method for manufacturing a porous metal body according to the present invention includes: a surface oxidizing step of heating a titanium-containing powder in an atmosphere containing oxygen at a temperature of 250° C. or more for 30 minutes or more to provide a surface-oxidized powder; and a sintering step of depositing the surface-oxidized powder in a dry process, and sintering the surface-oxidized powder by heating it in a reduced pressure atmosphere or an inert atmosphere at a temperature of 950° C. or more.