Provided is a plurality of flaky magnetic metal particles of the embodiments, each flaky magnetic metal particle having a flat surface provided with either or both of a plurality of concavities and a plurality of convexities arranged in a first direction, each concavity or convexity having a width of 0.1 μm or more, a length of 1 μm or more, and an aspect ratio of 2 or higher; and at least one first element selected from the group consisting of iron (Fe), cobalt (Co), and nickel (Ni), the flaky magnetic metal particles having an average thickness of between 10 nm and 100 μm inclusive and an average aspect ratio of between 5 and 10,000 inclusive.

The negative electrode active material according to the present embodiment includes alloy particle containing an alloy component and oxygen of 0.50 to 3.00 mass %. The alloy component contains Sn: 13.0 to 40.0 at % and Si: 6.0 to 40.0 at %. The alloy particle contains: one or two phases selected from a D0.sub.3 phase in which the Si content is from 0 to 5.0 at % and a δ phase in which the Si content is from 0 to 5.0 at %; one or two phases selected from an ε phase in which the Si content is from 0 to 5.0 at % and an η′ phase in which the Si content is from 0 to 5.0 at %; and an SiOx phase. The alloy particle has, in an X-ray diffraction profile, a peak having a largest integrated diffraction intensity in a range of 42.0 to 44.0 degrees of a diffraction angle 2θ.

A preparation method of improved sintered neodymium-iron-boron (Nd—Fe—B) casting strips includes the following steps: firstly nucleation assisted alloy particles used for sintered Nd—Fe—B casting strips are prepared, all elements are weighted as follows: 26.68-28% of Pr—Nd, 70-72.5% of Fe and 0.90-1% of B, and a Pr element in two elements of Pr—Nd accounts for 0-30 wt %; the compounded materials are smelted and poured to obtain alloy strips, then the alloy strips are crushed into particles with diameter of 1-10 mm; secondly, Nd—Fe—B casting strips are prepared: the prepared intermediate materials are smelted and melted into molten steel, and then are refined; after the intermediate materials are fully melted, the nucleation assisted alloy particles are added; and after the nucleation assisted alloy particles are added, smelting is performed for 3-15 minutes pouring is performed, and final Nd—Fe—B alloy casting strips are obtained.

A pressed powder material according to embodiments is a pressed powder material including first magnetic metal particles having a first magnetic metal phase containing Fe and Co; and second magnetic metal particles having a second magnetic metal phase containing Fe, in which when the amounts of Co with respect to the total amounts of Fe and Co of the first and second magnetic metal particles are designated as Co1 and Co2, respectively, the ratio of Co2 to Co1 (Co2/Co1) is from 0 to 0.5, the average value of the ratio of the major axis to the minor axis is 2 or greater for the first magnetic metal particles and 1 or greater for the second magnetic metal particles, the second magnetic metal particles are present between the particles of the first magnetic metal particles, and the average value of the major axis of the second magnetic metal particles is equal to or longer than the average value of the major axis of the first magnetic metal particles.

A pressed powder material according to embodiments is a pressed powder material including first magnetic metal particles having a first magnetic metal phase containing Fe and Co; and second magnetic metal particles having a second magnetic metal phase containing Fe, in which when the amounts of Co with respect to the total amounts of Fe and Co of the first and second magnetic metal particles are designated as Co1 and Co2, respectively, the ratio of Co2 to Co1 (Co2/Co1) is from 0 to 0.5, the average value of the ratio of the major axis to the minor axis is 2 or greater for the first magnetic metal particles and 1 or greater for the second magnetic metal particles, the second magnetic metal particles are present between the particles of the first magnetic metal particles, and the average value of the major axis of the second magnetic metal particles is equal to or longer than the average value of the major axis of the first magnetic metal particles.

This disclosure is directed to sintered bodies comprising grains and a grain boundary composition, wherein: (a) the grains comprise a composition substantially represented by a formula G.sub.2M.sub.14B, where G is Nd, Dy, Pr, Tb, or a combination thereof, and M is Co, Fe, Ni, or a combination thereof, wherein the grains are optionally doped with one or more rare earth elements; and (b) the grain boundary composition is an alloy composition substantially represented by the formula: Nd.sub.8.5-12.5Dy.sub.35-45Co.sub.32-41Cu.sub.3-6.5Fe.sub.1.5-5, wherein the subscript values are atom percent relative to the total composition of the alloy composition. Corresponding populations of particles are also disclosed.

This disclosure is directed to sintered bodies comprising grains and a grain boundary composition, wherein: (a) the grains comprise a composition substantially represented by a formula G.sub.2M.sub.14B, where G is Nd, Dy, Pr, Tb, or a combination thereof, and M is Co, Fe, Ni, or a combination thereof, wherein the grains are optionally doped with one or more rare earth elements; and (b) the grain boundary composition is an alloy composition substantially represented by the formula: Nd.sub.8.5-12.5Dy.sub.35-45Co.sub.32-41Cu.sub.3-6.5Fe.sub.1.5-5, wherein the subscript values are atom percent relative to the total composition of the alloy composition. Corresponding populations of particles are also disclosed.

A soft magnetic powder that can exhibit desirable soft magnetic characteristics. A dust core using the soft magnetic powder is also provided. The soft magnetic powder includes: a soft magnetic powder layer of an unoxidized soft magnetic material; a second oxide layer as an oxide with iron or boron residing around the soft magnetic powder layer; and a first oxide layer of an iron oxide residing around the second oxide layer. The first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface.

A soft magnetic powder that can exhibit desirable soft magnetic characteristics. A dust core using the soft magnetic powder is also provided. The soft magnetic powder includes: a soft magnetic powder layer of an unoxidized soft magnetic material; a second oxide layer as an oxide with iron or boron residing around the soft magnetic powder layer; and a first oxide layer of an iron oxide residing around the second oxide layer. The first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface.

A samarium-iron-nitrogen-based magnetic material containing Sm, Fe, N, Ti, and Co at a content of 2.5 at % or less. A content of the Sm may be 7 at % to 10 at %, a content of the Fe may be 65 at % to 80 at %, a content of the N may be 13 at % to 16 at %, and a content of the Ti may be 0.5 at % to 1.5 at %.