A method of surface modification of a metal or metal alloy powder includes the steps of providing a metal or metal alloy powder including copper, gold, or silver and having an average diameter in the micron range; providing a powder having an alloying element to form an alloying element powder. The alloying element powder particles have an average diameter less than 10 micron and no more than half the average diameter of the metal or metal alloy powder particles; mixing the powders to form a mixed powder; heating the mixed powder in an atmosphere of reducing gas to a first temperature T1; after temperature T1 is reached, replacing the reducing gas atmosphere with an inert gas atmosphere and maintaining the temperature at a second temperature T2 for a predetermined time. The alloying element is capable of diffusing in the metal or metal alloy element at temperature T2.

A method of surface modification of a metal or metal alloy powder includes the steps of providing a metal or metal alloy powder including copper, gold, or silver and having an average diameter in the micron range; providing a powder having an alloying element to form an alloying element powder. The alloying element powder particles have an average diameter less than 10 micron and no more than half the average diameter of the metal or metal alloy powder particles; mixing the powders to form a mixed powder; heating the mixed powder in an atmosphere of reducing gas to a first temperature T1; after temperature T1 is reached, replacing the reducing gas atmosphere with an inert gas atmosphere and maintaining the temperature at a second temperature T2 for a predetermined time. The alloying element is capable of diffusing in the metal or metal alloy element at temperature T2.

A method for forming films on particles of powder includes diffusing the powder by leading the powder into a jet nozzle and ejecting a jet flow of the powder; leading the diffused particles of powder, a raw material gas, and a reaction gas activated by atmospheric pressure plasma, into a reaction container, and forming a swirl flow in the container; and forming the films on the diffused particles of powder by reaction of a raw material gas and an activated reaction gas in the container. An apparatus is also disclosed having a reaction container with a peripheral wall having a round section in plan view and a jet nozzle for a powder source, raw material gas, and atmospheric pressure plasma sources are coupled to and enter the container at an angle with a radius thereof thereby forming a swirl flow to form a film on the powder.

A method for forming films on particles of powder includes diffusing the powder by leading the powder into a jet nozzle and ejecting a jet flow of the powder; leading the diffused particles of powder, a raw material gas, and a reaction gas activated by atmospheric pressure plasma, into a reaction container, and forming a swirl flow in the container; and forming the films on the diffused particles of powder by reaction of a raw material gas and an activated reaction gas in the container. An apparatus is also disclosed having a reaction container with a peripheral wall having a round section in plan view and a jet nozzle for a powder source, raw material gas, and atmospheric pressure plasma sources are coupled to and enter the container at an angle with a radius thereof thereby forming a swirl flow to form a film on the powder.

The invention provides an iron-based metallic glass alloy powder including: Fe as the main component; a metalloid element group including Si, B, and C; a small amount of Mo to improve the degree-of-supercooling; and the addition of Cr and Ni to increase corrosion resistance, where the total amount of the metalloid element group, the amount of the degree-of-supercooling improvement element and the total amount of the elements to increase corrosion resistance are set within predetermined ranges.

Methods of fabricating structures, such as parts for use in nuclear power generation systems, are described herein. A representative method of fabricating a part for a nuclear reactor system includes coating a plurality of particles of a powder of a first material with a second material, and then pressing and/or heating the coated powder into a monolithic structure. The second material can be substantially solidly insoluble with the first material such that, after pressing and/or heating, the particles of the first material define grains of the monolithic structure and the second material substantially encapsulates the grains in the monolithic structure. The first material can be susceptible to corrosion by a select process, and the second material can be resistant to corrosion by the select process such that the bulk first material of the monolithic structure is resistant to corrosion by the select process.

Composite particles sinterable at a low temperature and allow forming a sintered body that exhibits a large extension are provided. The composite particles include microparticles having an average crystallite diameter of 0.6 to 10 μm and containing a metal, and nanoparticles adhered to a surface of the microparticle, having an average crystallite diameter of 3 to 100 nm, and containing a metal of a same kind as the metal contained in the microparticle.

Composite particles sinterable at a low temperature and allow forming a sintered body that exhibits a large extension are provided. The composite particles include microparticles having an average crystallite diameter of 0.6 to 10 μm and containing a metal, and nanoparticles adhered to a surface of the microparticle, having an average crystallite diameter of 3 to 100 nm, and containing a metal of a same kind as the metal contained in the microparticle.

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.

A silver powder containing: silver particles; and an adherent that is attached to surfaces of the silver particles and contains a metal oxide that has a melting point lower than a melting point of silver.