A composite material including a metallic phase and plurality of particles dispersed in the metallic phase. The plurality of particles is a carbon-based material; the metallic phase contains a main element, a first element, and a second element; the coating layer of each of the plurality of particles is carbide of the second element. The main element is copper; the first element is a metallic element having a lower surface tension than copper; the second element is at least one selected from the group consisting of beryllium, silicon, titanium, chromium, zirconium, niobium, hafnium, and tantalum.

The present invention addresses the problem of providing a sintered alloy valve guide capable of inhibiting valve adhesion even in a high-temperature environment. The problem can be solved by a sintered alloy valve guide impregnated with a lubricating oil including pores that are sealed on the valve guide outer circumferential surface. More particularly, the problem is solved by the sealing step of performing a sealing treatment of pores on the outer circumferential surface of a sintered body impregnated with a lubricating oil.

A method of forming a projectile for use in a firearm ammunition cartridge, the method including mixing a first material and a second material having different densities to produce a core mixture, disposing the core mixture in a die, heating the core mixture to the melting point, removing the core mixture from the die, quenching the core mixture, and plating the core mixture with a jacket material.

A preparation method for a W—Cu composite plate with a Cu phase in finger-shaped gradient distribution is provided. The method includes adding WO.sub.X powder obtained with ammonium metatungstate as a raw material into W powder through a combustion synthesis method, adding a binder and a pore-forming agent to prepare a slurry, then performing tape casting, soaking in water and sintering to obtain a W framework with pores in finger-shaped distribution, and then infiltrating Cu to obtain a target product. The Cu phase in the W—Cu composite material prepared by the present method is distributed in a finger-shaped gradient manner from an infiltration surface to the interior of a specimen, the Cu phase and the W phase are mutually pinned, and the W—Cu interface has good bonding strength. The present method has the characteristics of adjustable material component performance, simple process, low cost, suitability for large-scale production and the like.

In a method for producing nanoparticles of copper selenide, a flowable copper precursor is formed by combining a copper starting material and a ligand, and a flowable selenium precursor is formed by suspending a selenium starting material in a liquid. Then a flowable copper-selenium mixture including a lower-polarity solvent is formed by combining the flowable copper precursor and the flowable selenium precursor. The flowable copper-selenium mixture is conducted through at least one heating unit, and the nanoparticles of copper selenide are isolated in an oxygen-depleted environment. The isolation includes combining a solution containing the nanoparticles of copper selenide and a deoxygenated, higher-polarity solvent to precipitate the nanoparticles.

To provide a metal particle composition having excellent oxidation resistance, which does not require a transition metal catalyst and can be applied to existing metal particles, a method for producing the metal particle composition, and a paste. The metal particle composition contains, with respect to 100 parts by mass of metal particles, 0.1 to 5 parts by mass of a compound (A) having a structure represented by the following general formula (I):

##STR00001## in which R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group, R.sup.3 and R.sup.4 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group, an aryl group, or an aralkyl group.

A thermoelectric material of the present invention includes copper, tin, and sulfur, wherein a ratio A/B of the number A of copper atoms to the number B of tin atoms is 0.5 to 2.5 and a content of a metal element other than copper and tin is 5 mol % or less with respect to total metal elements. Additionally, the thermoelectric material of the present invention has a thermal conductivity less than 1.0 W/(m.Math.K) at 200 to 400° C.

Disclosed herein are systems and methods for synthesis of spheroidized metal or metal alloy powders using microwave plasma processing. In some embodiments, the metal or metal alloy may comprise a highly ductile, soft, and/or malleable metal or metal alloy such that machining of the metal or metal alloy is difficult or impossible. In some embodiments, a volatile material is dispersed within the metal or metal alloy feedstock to enable machining and pre-processing of the feedstock. In some embodiments, the dispersed volatile material alters the physical properties of the feedstock, such that the metal or metal alloy, which is difficult to machine due to high ductility, softness, and/or malleability, is easily machined in a pre-processing step. In some embodiments, the pre-processed feedstock, can be fed into a plasma processing apparatus. In some embodiments, the volatile material dispersed within the feedstock material may be vaporized upon exposure to the microwave plasma apparatus. In some embodiments, plasma processing of the pre-processed feedstock material may synthesize pure, spheroidized metal or metal alloy particles, with substantially no contamination of the volatile material ion the final product.

A mixed powder for powder metallurgy comprises: an iron-based powder; and a lubricant, wherein the lubricant consists of a low-melting-point lubricant having a melting point of 86° C. or less and a high-melting-point lubricant having a melting point of more than 86° C., the low-melting-point lubricant has at least one of an amide group, an ester group, an amino group, and a carboxyl group, a ratio R1 of the low-melting-point lubricant to whole of the lubricant is 5 mass % or more and less than 90 mass %, a ratio R2 of a mass of a free lubricant to a mass of a binding lubricant is 0 or more and 15 or less, and an amount R3 of the low-melting-point lubricant contained as the free lubricant is less than 0.10 parts by mass with respect to 100 parts by mass of the iron-based powder.

The present disclosure provides a method for preparing a powder material and an application thereof. The preparation method includes: obtaining an initial alloy ribbon including a matrix phase and a dispersed particle phase by solidifying an alloy melt, and then removing the matrix phase in the initial alloy ribbon while retaining the dispersed particle phase, so as to obtain a powder material composed of original dispersed particle phase. The preparation method of the present disclosure is simple in process and can prepare multiple powder materials of nano-level, sub-micron-level and micro-level. The powder materials have good application prospects in the fields such as catalytic materials, powder metallurgy, composite materials, wave-absorbing materials, sterilization materials, metal injection molding, 3D printing and coating.