The present invention is to provide powder made of iron-based metallic glass, the corrosion resistance of which is improved over the conventional powder made of iron-based metallic glass. The basic composition includes a group of iron-based metallic elements that predominantly has Fe, a group of metalloid elements that consists of Si, B, P, and C, and a little amount of a group of elements for improving the degree of supercooling that consists of either or both of Nb and Mo. The powder made of the iron-based metallic glass is obtained by adding to the basic composition an element for improving the corrosion resistance. The obtained powder made of the iron-based metallic glass has an excellent corrosion resistance, an excellent magnetic property, and an excellent insulating property.

The present invention is to provide powder made of iron-based metallic glass, the corrosion resistance of which is improved over the conventional powder made of iron-based metallic glass. The basic composition includes a group of iron-based metallic elements that predominantly has Fe, a group of metalloid elements that consists of Si, B, P, and C, and a little amount of a group of elements for improving the degree of supercooling that consists of either or both of Nb and Mo. The powder made of the iron-based metallic glass is obtained by adding to the basic composition an element for improving the corrosion resistance. The obtained powder made of the iron-based metallic glass has an excellent corrosion resistance, an excellent magnetic property, and an excellent insulating property.

A sliding member of the present invention includes a coating on a base material. The coating contains hard metal particles and corrosion-resistant metal particles that have hardness lower than that of the hard metal particles. The hard metal particles contain particles that have at least Vickers hardness of 600 Hv or higher. The corrosion-resistant metal particles are made of at least one kind of metal selected from the group consisting of copper (Cu), cobalt (Co), chromium (Cr), and nickel (Ni), or are made of an alloy containing said metal. The coating has a cross section in which the hard metal particles are dispersed in an island manner in a particle aggregate of the corrosion-resistant metal particles and in which an area ratio of the corrosion-resistant metal particles is 30% or larger. Thus, corrosion of the hard metal particles in the coating is prevented, whereby the sliding member maintains wear resistance for a long time.

A method for manufacturing magnetic alloy powder constituted by magnetic grains whose alloy phase is coated with an oxide film, includes: providing a material powder for magnetic alloy whose Fe content is 96.5 to 99 percent by mass and which also contains Si and at least one of non-Si elements (element M) that oxidize more easily than Fe; and heat-treating the material powder and thus forming an oxide film on a surface of each grain constituting the material powder, to obtain a magnetic alloy powder, wherein a content of Fe in the alloy phase is higher than in the material powder; and at a location in the oxide film where its content of Si is in element distributions in a film thickness direction is highest, the content of Si is higher than a content of Fe, and also higher than its content of element M, at the location.

An iron-based alloy powder for powder metallurgy contains 2.0 mass % to 5.0 mass % of Cu, the balance being Fe and incidental impurities. From 1/10 to 8/10 of the Cu is diffusion bonded in powder-form to the surfaces of iron powder that serves as a raw material for the iron-based alloy powder, and the remainder of the Cu is contained in this iron powder as a pre-alloy. The iron-based alloy powder has superior compressibility to conventional Cu pre-alloyed iron-based alloy powders and enables production of a high strength sinter-forged member even when sintered at a lower temperature than conventional iron-based alloy powders containing mixed Cu powder.

An electric actuator has a housing, an electric motor mounted on the housing, a speed reduction mechanism, and a ball screw mechanism that converts the rotational motion of the electric motor to axial linear motion of a drive shaft. An annular groove is formed on an open end of the blind bore of the housing. The sleeve is axially immovably secured by a annular stopper ring fit into the annular groove. The stopper ring has one notch and a recess formed on its inner circumference near each of its two ends of the stopper ring. A contour of each recess has a circular arc portion and a flat portion. The circular arc portion has a predetermined radius of curvature. The flat portion tangentially extends from the circular arc portion. A width of the opening of the recess is smaller than a diameter of the circular arc portion.

The disclosure relates to sintering compositions that can be used in three-dimensional printing or additive manufacturing processes. The sintering compositions generally include one or more metallic iron-containing powders and a minor amount of a boron-containing powder as a sintering aid. Sintered models or products formed from the sintering compositions have substantially improved density and surface roughness values relative to models formed without the boron-containing powder.

The disclosure relates to sintering compositions that can be used in three-dimensional printing or additive manufacturing processes. The sintering compositions generally include one or more metallic iron-containing powders and a minor amount of a boron-containing powder as a sintering aid. Sintered models or products formed from the sintering compositions have substantially improved density and surface roughness values relative to models formed without the boron-containing powder.

This sintered R-T-B based rare-earth magnet includes: R.sub.2Fe.sub.14B type compound crystal grains, including a light rare-earth element RL (which includes at least one of Nd and Pr) as a major rare-earth element R, as main phases; and a heavy rare-earth element RH (which includes at least one of Dy and Tb). Before its surface region is removed, the sintered R-T-B based rare-earth magnet has no layer including the rare-earth element R at a high concentration in that surface region. The sintered R-T-B based rare-earth magnet has a portion in which coercivity decreases gradually from its surface region toward its core portion. The difference in the amount of TRE between a portion of the sintered R-T-B based rare-earth magnet that reaches a depth of 500 μm as measured from its surface region toward its core portion and the core portion of the sintered R-T-B based rare-earth magnet is 0.1 through 1.0.

A method for producing a NdFeB system sintered magnet. The method includes: a hydrogen pulverization process, in which coarse powder of a NdFeB system alloy is prepared by coarsely pulverizing a lump of NdFeB system alloy by making this lump occlude hydrogen; a fine pulverization process, in which fine powder is prepared by performing fine pulverization for further pulverizing the coarse powder; a filling process, in which the fine powder is put into a filling container; an orienting process, in which the fine powder in the filling container is oriented; and a sintering process, in which the fine powder after the orienting process is sintered as held in the filling container. The processes from hydrogen pulverization through orienting are performed with neither dehydrogenation heating nor evacuation each for desorbing hydrogen occluded in the hydrogen pulverization process. The processes from hydrogen pulverization through sintering are performed in an oxygen-free atmosphere.