Method for manufacturing porous aluminum

Abstract

A method for manufacturing porous aluminum, comprising steps of: press-molding a powder mixture of aluminum powder and supporting powder under pressure of not lower than 200 MPa, the aluminum powder having a volume ratio of 5 to 30% with respect to a total volume of the powder mixture; sintering a press-molded body with heat treatment in an inert atmosphere within a temperature range of not lower than a melting point of the aluminum powder and lower than 700° C.; and removing the supporting powder from a sintered body. With this method, the porous aluminum having a high porosity and a uniform pore diameter, which is suitable for a current collector in a lithium-ion secondary battery and for a variety of filters, is readily manufactured.

1 . A method for manufacturing porous aluminum, comprising the steps of:
 press-molding a powder mixture of aluminum powder and supporting powder under pressure of not lower than 200 MPa, the aluminum powder having a volume ratio of 5 to 30% with respect to a total volume of the powder mixture;   sintering a molded body with heat treatment in an inert atmosphere within a temperature range of not lower than a melting point of the aluminum powder and lower than 700° C.; and   removing the supporting powder from a sintered body.   
     
     
         2 . The method for manufacturing porous aluminum according to  claim 1  wherein in the press-molding step, the powder mixture in  claim 1  is press-molded in a composite state combined with a metal plate or metal plates under pressure of not lower than 200 MPa,
 wherein in the sintering step, the thus obtained press-molded body is sintered with heat treatment in an inert atmosphere within a temperature range of not lower than a melting point of the aluminum powder and lower than 700° C., and 
 wherein in the removing step, the supporting powder is removed from a the thus obtained sintered body. 
 
     
     
         3 . The method for manufacturing porous aluminum according to  claim 1 , wherein given that a particle diameter and a volume of the aluminum powder are denoted respectively by dal and Val, and that a particle diameter and a volume of the supporting powder are denoted respectively by ds and Vs, a coverage area percentage C of a surface of the supporting powder covered with the aluminum powder, expressed by C={(Val×ds)/(4Vs×dal)}×100, is not less than 70%. 
     
     
         4 . The method for manufacturing porous aluminum according to  claim 1 , wherein the supporting powder is made of sodium chloride, potassium chloride, or a mixture of the sodium chloride and the potassium chloride. 
     
     
         5 . The method for manufacturing porous aluminum according to  claim 1 , wherein the aluminum powder contains at least one of pure aluminum powder and aluminum alloy powder. 
     
     
         6 . The method for manufacturing porous aluminum according to  claim 5 , wherein the aluminum powder contains additive element powder. 
     
     
         7 . The method for manufacturing porous aluminum according to  claim 2 , wherein given that a particle diameter and a volume of the aluminum powder are denoted respectively by dal and Val, and that a particle diameter and a volume of the supporting powder are denoted respectively by ds and Vs, a coverage area percentage C of a surface of the supporting powder covered with the aluminum powder, expressed by C={(Val×ds)/(4Vs×dal)}×100, is not less than 70%. 
     
     
         8 . The method for manufacturing porous aluminum according to  claim 2 , wherein the supporting powder is made of sodium chloride, potassium chloride, or a mixture of the sodium chloride and the potassium chloride. 
     
     
         9 . The method for manufacturing porous aluminum according to  claim 3 , wherein the supporting powder is made of sodium chloride, potassium chloride, or a mixture of the sodium chloride and the potassium chloride. 
     
     
         10 . The method for manufacturing porous aluminum according to  claim 2 , wherein the aluminum powder contains at least one of pure aluminum powder and aluminum alloy powder. 
     
     
         11 . The method for manufacturing porous aluminum according to  claim 3 , wherein the aluminum powder contains at least one of pure aluminum powder and aluminum alloy powder. 
     
     
         12 . The method for manufacturing porous aluminum according to  claim 4 , wherein the aluminum powder contains at least one of pure aluminum powder and aluminum alloy powder.