Metal powder for powder metallurgy, compound, granulated powder, and sintered body

Abstract

A metal powder comprising particles, which contain Fe, Cr, C and Si, and in which 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 consisting of Ti, V, Y, Zr, Nb, Hf, and Ta, 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 in the periodic table than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01% by mass or more and 0.5% by mass or less, and the second element is contained in a proportion of 0.01% by mass or more and 0.5% by mass or less.

What is claimed is: 
     
         1 . A metal powder for powder metallurgy, comprising particles, which contain
 Fe as a principal component,   Cr in a proportion of 10% by mass or more and 30% by mass or less,   C in a proportion of 0.1% by mass or more and 2% by mass or less, and   Si in a proportion of 0.2% by mass or more and 1.5% by mass or less, and in which   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 consisting of Ti, V, Y, Zr, Nb, Hf, and Ta, 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 in the periodic table than that of the first element is defined as a second element,   the first element is contained in a proportion of 0.01% by mass or more and 0.5% by mass or less, and   the second element is contained in a proportion of 0.01% by mass or more and 0.5% by mass or less, wherein   the number of crystals in the cross section of the particle is 1 or more and 5 or less on average.   
     
     
         2 . The metal powder for powder metallurgy according to  claim 1 , wherein
 the crystal contains Fe as a principal component, and   the particle further includes a region, which has a smaller volume than the crystal, and in which the ratio of the content of Si to the content of Fe is higher than in the crystal.   
     
     
         3 . The metal powder for powder metallurgy according to  claim 1 , wherein in the cross section of the particle, the circle equivalent diameter of the crystal is 1% or more and 100% or less the circle equivalent diameter of the particle. 
     
     
         4 . The metal powder for powder metallurgy according to  claim 1 , wherein the crystal has a martensite crystal structure. 
     
     
         5 . A compound, comprising the metal powder for powder metallurgy according to  claim 1  and a binder which binds the particles of the metal powder for powder metallurgy to one another. 
     
     
         6 . A compound, comprising the metal powder for powder metallurgy according to  claim 2  and a binder which binds the particles of the metal powder for powder metallurgy to one another. 
     
     
         7 . A compound, comprising the metal powder for powder metallurgy according to  claim 3  and a binder which binds the particles of the metal powder for powder metallurgy to one another. 
     
     
         8 . A compound, comprising the metal powder for powder metallurgy according to  claim 4  and a binder which binds the particles of the metal powder for powder metallurgy to one another. 
     
     
         9 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 1 . 
     
     
         10 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 2 . 
     
     
         11 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 3 . 
     
     
         12 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 4 . 
     
     
         13 . A sintered body, wherein the sintered body is produced by sintering the metal powder for powder metallurgy according to  claim 1 . 
     
     
         14 . A sintered body, wherein the sintered body is produced by sintering the metal powder for powder metallurgy according to  claim 2 . 
     
     
         15 . A sintered body, wherein the sintered body is produced by sintering the metal powder for powder metallurgy according to  claim 3 . 
     
     
         16 . A sintered body, wherein the sintered body is produced by sintering the metal powder for powder metallurgy according to  claim 4 .