The present disclosure is directed at methods of preparing rare earth-based permanent magnets having improved coercivity and remanence, the method comprising one or more steps comprising: (a) homogenizing a first population of particles of a first GBM alloy with a second population of particles of a second core alloy to form a composite alloy preform, the first GBM alloy being substantially represented by the formula: AC.sub.bR.sub.xCo.sub.yCu.sub.dM.sub.z, the second core alloy being substantially represented by the formula G.sub.2Fe.sub.14B, where AC, R, M, G, b, x, y, and z are defined; (b) heating the composite alloy preform particles to form a population of mixed alloy particles; (c) compressing the mixed alloy particles, under a magnetic field of a suitable strength to align the magnetic particles with a common direction of magnetization and inert atmosphere, to form a green body; (d) sintering the green body; and (e) annealing the sintered body. Particular embodiments include magnets comprising neodymium-iron-boron core alloys, including Nd.sub.2Fe.sub.14B.

The present disclosure is directed at methods of preparing rare earth-based permanent magnets having improved coercivity and remanence, the method comprising one or more steps comprising: (a) homogenizing a first population of particles of a first GBM alloy with a second population of particles of a second core alloy to form a composite alloy preform, the first GBM alloy being substantially represented by the formula: AC.sub.bR.sub.xCo.sub.yCu.sub.dM.sub.z, the second core alloy being substantially represented by the formula G.sub.2Fe.sub.14B, where AC, R, M, G, b, x, y, and z are defined; (b) heating the composite alloy preform particles to form a population of mixed alloy particles; (c) compressing the mixed alloy particles, under a magnetic field of a suitable strength to align the magnetic particles with a common direction of magnetization and inert atmosphere, to form a green body; (d) sintering the green body; and (e) annealing the sintered body. Particular embodiments include magnets comprising neodymium-iron-boron core alloys, including Nd.sub.2Fe.sub.14B.

A multistage centrifugal atomizer comprises an outer shell that contains an inlet port and an outlet port and that encloses a tundish, a first inclined rotating surface and a second inclined rotating surface. The first inclined rotating surface is opposedly disposed to the second inclined rotating surface. The inlet is used to introduce a molten material into the multistage atomizer and the outlet is used to remove ultrafine particles having a D50 of less than 20 micrometers.

Disclosed herein is a method comprising disposing a container containing a metal and/or ferromagnetic solid and abrasive particles in a static magnetic field; where the container is surrounded by an induction coil; activating the induction coil with an electrical current, to heat up the metallic or ferromagnetic solid to form a fluid; generating sonic energy to produce acoustic cavitation and abrasion between the abrasive particles and the container; and producing nanoparticles that comprise elements from the container, the metal and/or the ferromagnetic solid and the abrasive particles. Disclosed herein too is a composition comprising first metal or a first ceramic; and particles comprising carbides and/or nitrides dispersed therein. Disclosed herein too is a composition comprising nanoparticles comprising chromium carbide, iron carbide, nickel carbide, γ-Fe and magnesium nitride.

Disclosed herein is a method comprising disposing a container containing a metal and/or ferromagnetic solid and abrasive particles in a static magnetic field; where the container is surrounded by an induction coil; activating the induction coil with an electrical current, to heat up the metallic or ferromagnetic solid to form a fluid; generating sonic energy to produce acoustic cavitation and abrasion between the abrasive particles and the container; and producing nanoparticles that comprise elements from the container, the metal and/or the ferromagnetic solid and the abrasive particles. Disclosed herein too is a composition comprising first metal or a first ceramic; and particles comprising carbides and/or nitrides dispersed therein. Disclosed herein too is a composition comprising nanoparticles comprising chromium carbide, iron carbide, nickel carbide, γ-Fe and magnesium nitride.

Some variations provide a method of making a nanofunctionalized metal powder, comprising: providing metal particles containing metals selected from iron, nickel, copper, titanium, magnesium, zinc, silicon, lithium, silver, chromium, manganese, vanadium, bismuth, gallium, or lead; providing nanoparticles selected from zirconium, tantalum, niobium, or titanium; disposing the nanoparticles onto surfaces of the metal particles, in the presence of mixing media, thereby generating nanofunctionalized metal particles; and isolating and recovering the nanofunctionalized metal particles as a nanofunctionalized metal powder. Some variations provide a composition comprising a nanofunctionalized metal powder, the composition comprising metal particles and nanoparticles containing one or more elements selected from the group consisting of zirconium, tantalum, niobium, titanium, and oxides, nitrides, hydrides, carbides, or borides thereof, or combinations of the foregoing.

Some variations provide a method of making a nanofunctionalized metal powder, comprising: providing metal particles containing metals selected from iron, nickel, copper, titanium, magnesium, zinc, silicon, lithium, silver, chromium, manganese, vanadium, bismuth, gallium, or lead; providing nanoparticles selected from zirconium, tantalum, niobium, or titanium; disposing the nanoparticles onto surfaces of the metal particles, in the presence of mixing media, thereby generating nanofunctionalized metal particles; and isolating and recovering the nanofunctionalized metal particles as a nanofunctionalized metal powder. Some variations provide a composition comprising a nanofunctionalized metal powder, the composition comprising metal particles and nanoparticles containing one or more elements selected from the group consisting of zirconium, tantalum, niobium, titanium, and oxides, nitrides, hydrides, carbides, or borides thereof, or combinations of the foregoing.

A manufacturing method of alloy powder comprises a liquid film forming step, a supplying step and a dividing step. In the liquid film forming step, a high speed fluid made of coolant liquid is shaped into a liquid film which has a predetermined thickness of 0.1 mm or more and receives a predetermined acceleration of 2.0×10.sup.4G or more along a thickness direction. In the supplying step, molten alloy which is not divided into a size of the predetermined thickness or less is supplied to the liquid film. In the dividing step, the molten alloy is divided into the size of the predetermined thickness or less by the high speed fluid to make alloy particles and keeping the alloy particles in the liquid film by the predetermined acceleration so that the alloy particles are continuously cooled in the high speed fluid.

A manufacturing method of alloy powder comprises a liquid film forming step, a supplying step and a dividing step. In the liquid film forming step, a high speed fluid made of coolant liquid is shaped into a liquid film which has a predetermined thickness of 0.1 mm or more and receives a predetermined acceleration of 2.0×10.sup.4G or more along a thickness direction. In the supplying step, molten alloy which is not divided into a size of the predetermined thickness or less is supplied to the liquid film. In the dividing step, the molten alloy is divided into the size of the predetermined thickness or less by the high speed fluid to make alloy particles and keeping the alloy particles in the liquid film by the predetermined acceleration so that the alloy particles are continuously cooled in the high speed fluid.

The invention relates to a method to form copper nanoparticles. The method comprises heating a solution comprising a copper precursor comprising at least one neat copper carboxylate in a concentration of at least 0.2 M, a stabilizer comprising an amine in a concentration equal or larger than the concentration of the copper precursor and optionally a solvent to a temperature T1 to form metallic copper. The solution is then heated to a temperature T2, with the temperature T2 being at least 10° C. higher than the temperature T1. The solution is heated from temperature T1 to temperature T2 with an average rate of at least 2 degrees per minute.

The invention further relates to copper nanoparticles obtainable by such method and to formulations comprising such nanoparticles.