A metal powder for powder metallurgy contains Co as a principal component, Cr at 16 mass % or more and 35 mass % or less, and Si at 0.3 mass % or more and 2.0 mass % or less, wherein when one element selected from Ti, V, Y, Zr, Nb, Hf, and Ta is a first element, and one element selected from the group and having a higher group number in the periodic table than that of the first element or having the same group number in the periodic table as that of the first element and a higher period number than that of the first element is a second element, the first element is at 0.01 mass % or more and 0.5 mass % or less, and the second element is at 0.01 mass % or more and 0.5 mass % or less.

A metal powder for powder metallurgy contains Co as a principal component, Cr at 16 mass % or more and 35 mass % or less, and Si at 0.3 mass % or more and 2.0 mass % or less, wherein when one element selected from Ti, V, Y, Zr, Nb, Hf, and Ta is a first element, and one element selected from the group and having a higher group number in the periodic table than that of the first element or having the same group number in the periodic table as that of the first element and a higher period number than that of the first element is a second element, the first element is at 0.01 mass % or more and 0.5 mass % or less, and the second element is at 0.01 mass % or more and 0.5 mass % or less.

Methods for reducing a concentration of hexavalent chromium within a first aluminum slurry by adding a reducing agent to form a second aluminum slurry are provided. The reducing agent causes a chemical reduction reaction with the hexavalent chromium compound of the first aluminum slurry to form a trivalent chromium compound within the second aluminum slurry such that a first weight ratio of hexavalent chromium to trivalent chromium in the first aluminum slurry is decreased to a second weight ratio of hexavalent chromium to trivalent chromium in the second aluminum slurry, with the second weight ratio being less than the first weight ratio.

Methods for reducing a concentration of hexavalent chromium within a first aluminum slurry by adding a reducing agent to form a second aluminum slurry are provided. The reducing agent causes a chemical reduction reaction with the hexavalent chromium compound of the first aluminum slurry to form a trivalent chromium compound within the second aluminum slurry such that a first weight ratio of hexavalent chromium to trivalent chromium in the first aluminum slurry is decreased to a second weight ratio of hexavalent chromium to trivalent chromium in the second aluminum slurry, with the second weight ratio being less than the first weight ratio.

A metallic nanoparticle dispersion includes metallic nanoparticles, a liquid carrier, and a dispersion-stabilizing compound according to Formulae I, II, III or IV,

##STR00001##

wherein Q represents the necessary atoms to form a substituted or unsubstituted a five or six membered heteroaromatic ring; M is selected from the group consisting of a proton, a monovalent cationic group and an acyl group; R1 and R2 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thioether, an ether, an ester, an amide, an amine, a halogen, a ketone and an aldehyde, R1 and R2 may represent the necessary atoms to form a five to seven membered ring; R3 to R5 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thiol, a thioether, a sulfone, a sulfoxide, an ether, an ester, an amide, an amine, a halogen, a ketone, an aldehyde, a nitrile and a nitro group; and R4 and R5 may represent the necessary atoms to form a five to seven membered ring.

A metallic nanoparticle dispersion includes metallic nanoparticles, a liquid carrier, and a dispersion-stabilizing compound according to Formulae I, II, III or IV,

##STR00001##

wherein Q represents the necessary atoms to form a substituted or unsubstituted a five or six membered heteroaromatic ring; M is selected from the group consisting of a proton, a monovalent cationic group and an acyl group; R1 and R2 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thioether, an ether, an ester, an amide, an amine, a halogen, a ketone and an aldehyde, R1 and R2 may represent the necessary atoms to form a five to seven membered ring; R3 to R5 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thiol, a thioether, a sulfone, a sulfoxide, an ether, an ester, an amide, an amine, a halogen, a ketone, an aldehyde, a nitrile and a nitro group; and R4 and R5 may represent the necessary atoms to form a five to seven membered ring.

Provided is a composition including a plurality of multi-metallic nanoparticles each consisting essentially of a core including at least one first metal (Me1) and a continuous shell including atoms of at least one second metal (Me2). Optionally, the continuous shell of Me2 atoms protects the Me1 atoms from oxidation at all temperatures less than 150° C.

Provided is a composition including a plurality of multi-metallic nanoparticles each consisting essentially of a core including at least one first metal (Me1) and a continuous shell including atoms of at least one second metal (Me2). Optionally, the continuous shell of Me2 atoms protects the Me1 atoms from oxidation at all temperatures less than 150° C.

A method of producing anisotropic magnetic powders comprising obtaining a precipitate containing an element R, iron and lanthanum from a solution including R, iron and lanthanum, wherein R is at least one selected from the group consisting of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu; obtaining an oxide containing R, iron and lanthanum from the precipitate; treating the oxide with a reducing gas to obtain a partial oxide; obtaining alloy particles by reduction diffusion of the partial oxide at a temperature in the range of 920° C. to 1200° C.; and nitriding the alloy particles to produce an anisotropic magnetic powder represented by the following general formula: R.sub.v-xFe.sub.(100-v-w-z)N.sub.wLa.sub.xW.sub.z, where 3≤v−x≤30, 5≤w≤15, 0.08≤x≤0.3, and 0≤z≤2.5.

A method of producing anisotropic magnetic powders comprising obtaining a precipitate containing an element R, iron and lanthanum from a solution including R, iron and lanthanum, wherein R is at least one selected from the group consisting of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu; obtaining an oxide containing R, iron and lanthanum from the precipitate; treating the oxide with a reducing gas to obtain a partial oxide; obtaining alloy particles by reduction diffusion of the partial oxide at a temperature in the range of 920° C. to 1200° C.; and nitriding the alloy particles to produce an anisotropic magnetic powder represented by the following general formula: R.sub.v-xFe.sub.(100-v-w-z)N.sub.wLa.sub.xW.sub.z, where 3≤v−x≤30, 5≤w≤15, 0.08≤x≤0.3, and 0≤z≤2.5.