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

Abstract

A metal powder for powder metallurgy according to the invention contains Fe as a principal component, Cr in a proportion of 15 mass % or more and 26 mass % or less, Ni in a proportion of 7 mass % or more and 22 mass % or less, Si in a proportion of 0.3 mass % or more and 1.2 mass % or less, and C in a proportion of 0.005 mass % or more and 0.3 mass % or less, wherein when two elements selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta are defined as a first element and a second element, the first element is contained in a proportion of 0.01 mass % or more and 0.5 mass % or less and the second element is contained in a proportion of 0.01 mass % or more and 0.5 mass % or less. Further, the metal powder for powder metallurgy preferably has an austenite crystal structure.

What is claimed is: 
     
         1 . A metal powder for powder metallurgy, comprising:
 Fe as a principal component;   Cr in a proportion of 15% by mass or more and 26% by mass or less;   Ni in a proportion of 7% by mass or more and 22% by mass or less;   Si in a proportion of 0.3% by mass or more and 1.2% by mass or less; and   C in a proportion of 0.005% by mass or more and 0.3% by mass or less, 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 consisting of Ti, V, Y, Zr, Nb, Hf, and Ta, and having a larger 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 larger 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.   
     
     
         2 . The metal powder for powder metallurgy according to  claim 1 , wherein the metal powder has an austenite crystal structure. 
     
     
         3 . The metal powder for powder metallurgy according to  claim 1 , wherein the ratio (X1/X2) of a value (X1) obtained by dividing the content (E1) of the first element by the mass number of the first element to a value (X2) obtained by dividing the content (E2) of the second element by the mass number of the second element is 0.3 or more and 3 or less. 
     
     
         4 . The metal powder for powder metallurgy according to  claim 1 , wherein the sum of the content of the first element and the content of the second element is 0.05% by mass or more and 0.6% by mass or less. 
     
     
         5 . The metal powder for powder metallurgy according to  claim 1 , further comprising Mo in a proportion of 1% by mass or more and 5% by mass or less. 
     
     
         6 . The metal powder for powder metallurgy according to  claim 1 , wherein the metal powder has an average particle diameter of 0.5 μm or more and 30 μm or less. 
     
     
         7 . 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. 
     
     
         8 . 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. 
     
     
         9 . 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. 
     
     
         10 . 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. 
     
     
         11 . A compound, comprising the metal powder for powder metallurgy according to  claim 5  and a binder which binds the particles of the metal powder for powder metallurgy to one another. 
     
     
         12 . A compound, comprising the metal powder for powder metallurgy according to  claim 6  and a binder which binds the particles of the metal powder for powder metallurgy to one another. 
     
     
         13 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 1 . 
     
     
         14 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 2 . 
     
     
         15 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 3 . 
     
     
         16 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 4 . 
     
     
         17 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 5 . 
     
     
         18 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 6 . 
     
     
         19 . A sintered body, wherein the sintered body is produced by sintering a metal powder for powder metallurgy containing:
 Fe as a principal component;   Cr in a proportion of 15% by mass or more and 26% by mass or less;   Ni in a proportion of 7% by mass or more and 22% by mass or less;   Si in a proportion of 0.3% by mass or more and 1.2% by mass or less; and   C in a proportion of 0.005% by mass or more and 0.3% by mass or less, and   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 larger 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 larger 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.   
     
     
         20 . The sintered body according to  claim 19 , wherein the sintered body includes a first region which is in the form of a particle and has a relatively high silicon oxide content and a second region which has a relatively lower silicon oxide content than the first region.