The present invention discloses a method for refining large-particle-size pure copper or copper alloy particles by high-energy ball milling, the method comprising the following steps: (1) using large-particle-size pure copper or copper alloy coarse particles as a raw material and cyclohexane or water as a process control agent, and crushing and refining the particles by high-energy ball milling to obtain small-particle-size copper or copper alloy powder; and (2) decreasing an oxygen content in the powder obtained in step (1) in a reducing atmosphere to obtain pure copper or copper alloy powder. In the present invention, by improving the overall process flow of the preparation method and the parameter conditions of each process step, the method greatly decreases energy consumption compared with existing copper powder preparation techniques. In addition, the method features a simple process and low production costs.

The present invention discloses a method for refining large-particle-size pure copper or copper alloy particles by high-energy ball milling, the method comprising the following steps: (1) using large-particle-size pure copper or copper alloy coarse particles as a raw material and cyclohexane or water as a process control agent, and crushing and refining the particles by high-energy ball milling to obtain small-particle-size copper or copper alloy powder; and (2) decreasing an oxygen content in the powder obtained in step (1) in a reducing atmosphere to obtain pure copper or copper alloy powder. In the present invention, by improving the overall process flow of the preparation method and the parameter conditions of each process step, the method greatly decreases energy consumption compared with existing copper powder preparation techniques. In addition, the method features a simple process and low production costs.

A method for producing a magnetic powder includes the steps of: mixing neodymium oxide, boron, and iron to prepare a first mixture; adding and mixing calcium to the first mixture to prepare a second mixture; mixing an alkali metal with the second mixture to prepare a third mixture; and placing a carbon sheet on the third mixture, placing silica sand (SiO.sub.2 sand) thereon, and then heating the same to a temperature of 800° C. to 1100° C.

A method for producing a magnetic powder includes the steps of: mixing neodymium oxide, boron, and iron to prepare a first mixture; adding and mixing calcium to the first mixture to prepare a second mixture; mixing an alkali metal with the second mixture to prepare a third mixture; and placing a carbon sheet on the third mixture, placing silica sand (SiO.sub.2 sand) thereon, and then heating the same to a temperature of 800° C. to 1100° C.

A powder production method includes providing an elongated workpiece and repeatedly contacting an outer surface of the elongated workpiece with a reciprocating cutter according to a predetermined at least one frequency to produce a powder. The powder includes a plurality of particles, wherein at least 95% of the produced particles have a diameter or maximum dimension ranging from about 10 μm to about 200 μm. A system for producing powders having a plurality of particles including a cutter and at least one controller is also provided herein.

A powder production method includes providing an elongated workpiece and repeatedly contacting an outer surface of the elongated workpiece with a reciprocating cutter according to a predetermined at least one frequency to produce a powder. The powder includes a plurality of particles, wherein at least 95% of the produced particles have a diameter or maximum dimension ranging from about 10 μm to about 200 μm. A system for producing powders having a plurality of particles including a cutter and at least one controller is also provided herein.

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 powder production method includes providing at least one elongated member including a ductile material; providing a rotating or vibrating cutter configured to repeatedly cut an end of the at least one elongated member to produce particles; and advancing the at least one elongated member or the cutter towards the other of the at least one elongated member or the cutter to cut the particles from the at least one elongated member to produce a powder comprising a plurality of the particles. The particles produced by the method can have a diameter ranging from about 10 μm to about 200 μm.

A powder production method includes providing at least one elongated member including a ductile material; providing a rotating or vibrating cutter configured to repeatedly cut an end of the at least one elongated member to produce particles; and advancing the at least one elongated member or the cutter towards the other of the at least one elongated member or the cutter to cut the particles from the at least one elongated member to produce a powder comprising a plurality of the particles. The particles produced by the method can have a diameter ranging from about 10 μm to about 200 μm.