Raw material powder containing metal powder as a main component is molded to form a metal powder molded body (3′), and the metal powder molded body (3′) is sintered to form a metal substrate (3). Further, a lubricating member (4) is made of an aggregate of graphite particles (13), and at least a part of a bearing surface (11) is formed of the fabricating member (4). The lubricating member (4) is fitted into the metal powder molded body (3′). After that, the metal powder molded body (3′) is sintered, and at this time, the lubricating member (4) is fixed onto the metal substrate (3) with a contraction force (F) generated in the metal powder molded body (3′).

Raw material powder containing metal powder as a main component is molded to form a metal powder molded body (3′), and the metal powder molded body (3′) is sintered to form a metal substrate (3). Further, a lubricating member (4) is made of an aggregate of graphite particles (13), and at least a part of a bearing surface (11) is formed of the fabricating member (4). The lubricating member (4) is fitted into the metal powder molded body (3′). After that, the metal powder molded body (3′) is sintered, and at this time, the lubricating member (4) is fixed onto the metal substrate (3) with a contraction force (F) generated in the metal powder molded body (3′).

An R-T-B based permanent magnet includes R-T-B based compounds as main-phase crystal grains. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. A two-grain boundary is contained between the two adjacent main-phase crystal grains. An average grain size of the main-phase crystal grains is 0.9 μm or more and 2.8 μm or less. A thickness of the two-grain boundary is 5 nm or more and 200 nm or less.

An R-T-B based permanent magnet includes R-T-B based compounds as main-phase crystal grains. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. A two-grain boundary is contained between the two adjacent main-phase crystal grains. An average grain size of the main-phase crystal grains is 0.9 μm or more and 2.8 μm or less. A thickness of the two-grain boundary is 5 nm or more and 200 nm or less.

An L10-FeNi magnetic powder has an average particle size of 50 nm to 1 μm, and an average value of sphericity P of 0.9 or more. The sphericity P is defined as P=Ls/Lr, where Lr is a perimeter of an L10-FeNi magnetic powder particle on an image of a microscope, and Ls is a perimeter of a perfect circle that has a same area as the L10-FeNi magnetic powder particle on the image for which Lr is calculated.

An L10-FeNi magnetic powder has an average particle size of 50 nm to 1 μm, and an average value of sphericity P of 0.9 or more. The sphericity P is defined as P=Ls/Lr, where Lr is a perimeter of an L10-FeNi magnetic powder particle on an image of a microscope, and Ls is a perimeter of a perfect circle that has a same area as the L10-FeNi magnetic powder particle on the image for which Lr is calculated.

A metal powder for powder metallurgy according to the invention contains Co as a principal component, Cr in a proportion of 25 to 32 mass %, Ni in a proportion of 5 to 15 mass %, Fe in a proportion of 0.5 to 2 mass %, W in a proportion of 4 to 10 mass %, Si in a proportion of 0.3 mass % to 1.5 mass %, and C in a proportion of 0.05 mass % to 0.8 mass %, wherein when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as 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 as that of the first element and a higher period number than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01 to 0.5 mass %, and the second element is contained in a proportion of 0.01 to 0.5 mass %.

A metal powder for powder metallurgy according to the invention contains Co as a principal component, Cr in a proportion of 25 to 32 mass %, Ni in a proportion of 5 to 15 mass %, Fe in a proportion of 0.5 to 2 mass %, W in a proportion of 4 to 10 mass %, Si in a proportion of 0.3 mass % to 1.5 mass %, and C in a proportion of 0.05 mass % to 0.8 mass %, wherein when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as 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 as that of the first element and a higher period number than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01 to 0.5 mass %, and the second element is contained in a proportion of 0.01 to 0.5 mass %.

A hydrogen storing alloy containing only a few impurities leading to a short circuit where the yield can be maintained even when the alloy is subjected to magnetic separation treatment. A hydrogen storing alloy includes a matrix phase having an AB5 type crystal structure, the alloy having a misch metal (referred to as “Mm”) in an A-site in an ABx composition and having any one or at least one of Ni, Al, Mn, and Co in a B-site in the ABx composition, wherein the ratio (referred to as “ABx”) of the total number of moles of elements comprising the B site to the total number of moles of elements comprising the A site is 5.00<ABx≦5.40; the content of Co is more than 0.0 mol % and less than 0.7 mol %; and residual magnetization is more than 0 emu/g and 0.020 emu/g or less.

An objective of the present invention is to provide a mixed powder for powder metallurgy that makes it possible to improve mold-filling ability and reduce spread in weight of molded bodies. The mixed powder for powder metallurgy according to the present invention is obtained by mixing a graphite powder with an average particle diameter D50 of 1.0 μm or more to 3.0 μm or less and D90 of 10 μm or less, without adding a binder, with an iron-based powder, while applying a sheer force. The thus obtained mixed powder for powder metallurgy according to the present invention is characterized by including the iron-based powder and the graphite powder present so as to be collected in concave portions of the iron-based powder.