Method for producing powder mixture for powder metallurgy, and method for producing sintered body

Abstract

The present invention provides a method for producing a powder mixture for powder metallurgy, which allows production of a green compact having both high density and high lubricity (low demolding force). The method, according to the present invention, for producing a powder mixture for powder metallurgy including an iron-base powder, a mechanical characteristic-improving powder and a lubricant, the method includes the steps of: mixing the iron-base powder and/or the mechanical characteristic-improving powder with an amide-based lubricant solution; removing a solvent in the solution; and coating the surface of the iron-base powder and/or the mechanical characteristic-improving powder with an amide-based lubricant.

1 . A method for producing a powder mixture for powder metallurgy including an iron-base powder, a mechanical characteristic-improving powder and a lubricant, the method comprising the steps of:
 mixing the iron-base powder and/or the mechanical characteristic-improving powder with an amide-based lubricant solution;   removing a solvent in the solution; and   coating the surface of the iron-base powder and/or the mechanical characteristic-improving powder with an amide-based lubricant.   
     
     
         2 . The method for producing the powder mixture for powder metallurgy according to  claim 1 , wherein 0.01 to 2.0 parts by mass of the amide-based lubricant is added to 100 parts by mass of total amount of the iron-base powder and the mechanical characteristic-improving powder. 
     
     
         3 . The method for producing a powder mixture for powder metallurgy according to  claim 1 , wherein the amide-based lubricant is composed of an aliphatic amide and/or an aliphatic bisamide. 
     
     
         4 . The method for producing a powder mixture for powder metallurgy according to  claim 3 , wherein the aliphatic amide is N-oleyl palmitic amide. 
     
     
         5 . The method for producing a powder mixture for powder metallurgy according to  claim 3 , wherein the aliphatic bisamide is ethylene-bis-oleic amide. 
     
     
         6 . The method for producing a powder mixture for powder metallurgy according to  claim 1 , wherein the mechanical characteristic-improving powder is composed of at least one element selected from the group consisting of copper, nickel, chromium, molybdenum, graphite and manganese sulfide. 
     
     
         7 . A method for producing a sintered body, comprising the steps of:
 mixing the iron-base powder and/or the mechanical characteristic-improving powder with an amide-based lubricant solution;   removing a solvent in the solution;   coating the surface of the iron-base powder and/or the mechanical characteristic-improving powder with an amide-based lubricant;   compression-molding the powder mixture for powder metallurgy obtained by the producing method; and   sintering.   
     
     
         8 . The method for producing a sintered body according to  claim 7 , wherein said compression molding is performed at ordinary temperature. 
     
     
         9 . The method for producing a sintered body according to  claim 7 , wherein 0.01 to 2.0 parts by mass of the amide-based lubricant is added to 100 parts by mass of total amount of the iron-base powder and the mechanical characteristic-improving powder. 
     
     
         10 . The method for producing a sintered body according to  claim 7 , wherein the amide-based lubricant is composed of an aliphatic amide and/or an aliphatic bisamide. 
     
     
         11 . The method for producing a sintered body according to  claim 10 , wherein the aliphatic amide is N-oleyl palmitic amide. 
     
     
         12 . The method for producing a sintered body according to  claim 10 , wherein the aliphatic bisamide is ethylene-bis-oleic amide. 
     
     
         13 . The method for producing a sintered body according to  claim 7 , wherein the mechanical characteristic-improving powder is composed of at least one element selected from the group consisting of copper, nickel, chromium, molybdenum, graphite and manganese sulfide.