Method of producing mixed powder for powder metallurgy, method of producing sintered body, and sintered body

Abstract

A method of producing a mixed powder for powder metallurgy comprises: mixing an iron-based powder with a Mo-containing powder and a Cu-containing powder, to obtain a raw material mixed powder; heat-treating the raw material mixed powder to cause Mo and Cu to diffusionally adhere to a surface of the iron-based powder, to obtain a partially diffusion-alloyed steel powder; and mixing the partially diffusion-alloyed steel powder with a graphite powder, to obtain a mixed powder for powder metallurgy, wherein the iron-based powder has an average particle size of 30 μm to 120 μm, a cuprous oxide powder is used as the Cu-containing powder, and the mixed powder for powder metallurgy has a chemical composition containing Mo: 0.2 mass % to 1.5 mass %, Cu: 0.5 mass % to 4.0 mass %, and C: 0.1 mass % to 1.0 mass %, with a balance being Fe and incidental impurities.

1 . A method of producing a mixed powder for powder metallurgy, the method comprising:
 mixing an iron-based powder with a Mo-containing powder and a Cu-containing powder, to obtain a raw material mixed powder;   heat-treating the raw material mixed powder to cause Mo and Cu to diffusionally adhere to a surface of the iron-based powder, to obtain a partially diffusion-alloyed steel powder; and   mixing the partially diffusion-alloyed steel powder with a graphite powder, to obtain a mixed powder for powder metallurgy,   wherein the iron-based powder has an average particle size of 30 μm to 120 μm,   a cuprous oxide powder is used as the Cu-containing powder, and   the mixed powder for powder metallurgy has a chemical composition containing Mo: 0.2 mass % to 1.5 mass %, Cu: 0.5 mass % to 4.0 mass %, and C: 0.1 mass % to 1.0 mass %, with a balance being Fe and incidental impurities.   
     
     
         2 . The method of producing a mixed powder for powder metallurgy according to  claim 1 ,
 wherein the Cu-containing powder has an average particle size of 5 μm or less.   
     
     
         3 . A method of producing a sintered body, the method comprising:
 forming a mixed powder for powder metallurgy obtained by the method of producing a mixed powder for powder metallurgy according to  claim 1 ; and   sintering the formed mixed powder.   
     
     
         4 . A sintered body obtained by the method of producing a sintered body according to  claim 3 . 
     
     
         5 . A method of producing a sintered body, the method comprising:
 forming a mixed powder for powder metallurgy obtained by the method of producing a mixed powder for powder metallurgy according to  claim 2 ; and   sintering the formed mixed powder.   
     
     
         6 . A sintered body obtained by the method of producing a sintered body according to  claim 5 .