A two-step diffusion method for preparing high-performance dual-main-phase sintered mischmetal-iron-boron magnet belongs to the preparing technical field of rare earth permanent magnet materials. The compositions of the two main phase alloys are RE-Fe—B (RE is Nd or Pr) and (Nd, MM)-Fe—B (MM is mischmetal), respectively. First, PrHoFe strip-casting alloy is used as a diffusion source. Next, a PrHo-rich layer is uniformly coated on the surface of (Nd, MM)-Fe—B hydrogen decrepitation powders. The higher anisotropic fields of Pr.sub.2Fe.sub.14B and Ho.sub.2Fe.sub.14B are used to improve the coercivity. Then, the ZrCu strip-casting alloy is used as a diffusion source. A Zr-rich layer is uniformly coated on the surface of the powders after the first-step diffusion, which prevents the growth of the MM-rich main phase grains during the sintering process and the inter-diffusion between the two main phases, thus obtaining high coercivity.

A method for preparing powders of hard alloys, such as Ti and Ti—Zr alloys, using a hydride-dehydride process, and powders produced by the process, are disclosed. The method can be used to manufacture brazing powders. The method is less hazardous and more cost effective than current methods, such as gas atomization, of preparing such braze materials.

There are provided a method for producing a magnetic refrigeration material whose magnetic transition temperature can be adjusted with high accuracy, and a magnetic refrigeration material whose magnetic transition temperature has been adjusted with high accuracy. The magnetic refrigeration material production method of the present invention includes the steps of: preparing a first predetermined magnetic refrigeration material and a second predetermined magnetic refrigeration material which differs from the first magnetic refrigeration material; and mixing the first magnetic refrigeration material and the second magnetic refrigeration material to obtain a third magnetic refrigeration material. The content of the first magnetic refrigeration material and the content of the second magnetic refrigeration material in the third magnetic refrigeration material are determined by the magnetic transition temperatures of the first magnetic refrigeration material and the second magnetic refrigeration material and by a target magnetic transition temperature of the third magnetic refrigeration material. The magnetic refrigeration material of the present invention includes at least a first predetermined magnetic refrigeration material and a second predetermined magnetic refrigeration material which differs from the first magnetic refrigeration material. The absolute value of the difference between the magnetic transition temperature of the present magnetic refrigeration material and a target magnetic transition temperature is 0.7 K or less.

A sintered R-T-B based magnet includes a main phase formed of an R.sub.2T.sub.14B compound and a grain boundary phase at grain boundaries of the main phase. The grain boundary phase contains an R-T-M compound (M is at least one selected from the group consisting of Ga, Cu, Zn, Al and Si) and an R-M compound. In any cross-section of the sintered R-T-B based magnet, a sum of an area ratio of the R-T-M compound and an area ratio of the R-M compound is not lower than 1.5% and not higher than 3.5%, the area ratio of the R-T-M compound is not lower than 0.4% and not higher than 2.5%, and the area ratio of the R-M compound is not lower than 0.4% and not higher than 2.5%.

In various embodiments, metallic alloy powders are utilized as feedstock, or to fabricate feedstock, utilized in additive manufacturing processes to form three-dimensional metallic parts. Such three-dimensional parts are fabricated by providing a powder bed containing particles each comprising a mixture and/or alloy of constituent elemental metals, forming a first layer of the part by (i) dispersing a binder into the powder bed, and (ii) curing the binder, the first layer of the shaped part comprising particles bound together by cured binder, disposing a layer of the particles over the first layer of the part, forming subsequent layers of the part, and then sintering the part.

A titanium carbonitride powder for use as a starting material for a hard material satisfies a D50 of from 2.0 μm to 6.0 μm and a D10/D90 of from 0.20 to 0.50, wherein D50 is a particle size at a cumulative percentage of 50% of a particle size distribution by volume, D10 is a particle size at a cumulative percentage of 10% of the particle size distribution by volume, and D90 is a particle size at a cumulative percentage of 90% of the particle size distribution by volume.

Some variations provide a system for producing a functionalized powder, comprising: an agitated pressure vessel; first particles and second particles contained within the agitated pressure vessel; a fluid contained within the agitated pressure vessel; an exhaust line for releasing the fluid from the agitated pressure vessel; and a means for recovering a functionalized powder containing the second particles disposed onto surfaces of the first particles. A preferred fluid is carbon dioxide in liquefied or supercritical form. The carbon dioxide may be initially loaded into the pressure vessel as solid carbon dioxide. The pressure vessel may be batch or continuous and is operated under reaction conditions to functionalize the first particles with the second particles, thereby producing a functionalized powder, such as nanofunctionalized metal particles in which nanoparticles act as grain refiners for a component ultimately produced from the nanofunctionalized metal particles. Methods for making the functionalized powder are also disclosed.

Some variations provide a system for producing a functionalized powder, comprising: an agitated pressure vessel; first particles and second particles contained within the agitated pressure vessel; a fluid contained within the agitated pressure vessel; an exhaust line for releasing the fluid from the agitated pressure vessel; and a means for recovering a functionalized powder containing the second particles disposed onto surfaces of the first particles. A preferred fluid is carbon dioxide in liquefied or supercritical form. The carbon dioxide may be initially loaded into the pressure vessel as solid carbon dioxide. The pressure vessel may be batch or continuous and is operated under reaction conditions to functionalize the first particles with the second particles, thereby producing a functionalized powder, such as nanofunctionalized metal particles in which nanoparticles act as grain refiners for a component ultimately produced from the nanofunctionalized metal particles. Methods for making the functionalized powder are also disclosed.

Some variations provide a system for producing a functionalized powder, comprising: an agitated pressure vessel; first particles and second particles contained within the agitated pressure vessel; a fluid contained within the agitated pressure vessel; an exhaust line for releasing the fluid from the agitated pressure vessel; and a means for recovering a functionalized powder containing the second particles disposed onto surfaces of the first particles. A preferred fluid is carbon dioxide in liquefied or supercritical form. The carbon dioxide may be initially loaded into the pressure vessel as solid carbon dioxide. The pressure vessel may be batch or continuous and is operated under reaction conditions to functionalize the first particles with the second particles, thereby producing a functionalized powder, such as nanofunctionalized metal particles in which nanoparticles act as grain refiners for a component ultimately produced from the nanofunctionalized metal particles. Methods for making the functionalized powder are also disclosed.

There is provided a method of manufacturing nanoparticles comprising the steps of feeding a core precursor into a plasma torch in a plasma reactor, thereby producing a vapor of silicon or alloy thereof; and allowing the vapor to migrate to a quenching zone of the plasma reactor, thereby cooling the vapor and allowing condensation of the vapor into a nanoparticle core made of the silicon or alloy thereof, wherein the quenching gas comprises a passivating gas precursor that reacts with the surface of the core in the quenching zone produce a passivation layer covering the core, thereby producing said nanoparticles. The present invention also relates to nanoparticles comprising a core covered with a passivation layer, the core being made of silicon or an alloy thereof, as well as their use, in particular in the manufacture of anodes.