Method for Preparing Nano-Sized Metal Powder Feedstock and Method for Producing Sintered Body Using the Feedstock

Abstract

A method for preparing a nano-sized metal powder feedstock comprises the steps of preparing a nano-sized metal powder, mixing the metal powder with a solution of an organic binder in a solvent, and wet-milling the mixture so that aggregates of the metal powder are uniformly formed. Further disclosed is a method for producing a sintered body using the feedstock.

1 . A method for preparing a nano-sized metal powder feedstock, comprising the steps of:
 preparing a nano-sized metal powder;   mixing the metal powder with a solution of an organic binder in a solvent; and   wet-milling the mixture so that aggregates of the metal powder are uniformly formed.   
     
     
         2 . The method according to  claim 1 , wherein the mixing step and the wet-milling step are simultaneously carried out. 
     
     
         3 . The method according to  claim 1 , wherein the metal powder is mixed with one or two organic binders. 
     
     
         4 . The method according to  claim 1 , wherein the organic binder is a water-soluble binder and the solvent is distilled water or alcohol. 
     
     
         5 . The method according to  claim 4 , wherein the water-soluble organic binder is stearic acid. 
     
     
         6 . The method according to  claim 1 , wherein the binder solution has a viscosity of 2 Pa·s or lower at 100˜200° C. 
     
     
         7 . The method according to  claim 1 , wherein the nano-sized metal powder is an Fe-based alloy powder and contains at least one metal selected from the group consisting of Ni, Cu, Mo and W. 
     
     
         8 . The method according to  claim 7 , wherein the nano-sized metal powder is an Fe—Ni powder whose Ni content is 2˜80 wt %. 
     
     
         9 . The method according to  claim 1 , wherein the mixing step further includes the sub-step of adding a surfactant to the mixture. 
     
     
         10 . The method according to  claim 9 , wherein the surfactant is added in an amount not exceeding 2 wt %. 
     
     
         11 . The method according to  claim 1 , wherein the mixing step and the wet-milling step are carried out in a state where atmospheric air is blocked. 
     
     
         12 . The method according to  claim 11 , wherein the mixing step and the wet-milling step are carried out in an inert gas or protective gas atmosphere. 
     
     
         13 . A method for producing a sintered body using a nano-sized metal powder, comprising the steps of:
 preparing a nano-sized metal powder feedstock prepared by the method according to  claim 1 ;   molding the nano-sized metal powder feedstock into a desired shape;   debinding the molded body; and   sintering the debound body.   
     
     
         14 . The method according to  claim 13 , where the molding step is carried out by injection molding or extrusion molding. 
     
     
         15 . The method according to  claim 14 , where the debinding step is carried out by heating the molded body to about 300° C. to about 500° C. at a rate 3˜10° C./min. 
     
     
         16 . The method according to  claim 14 , where the sintering step is carried out by sintering the debound body at 500˜1,000° C. 
     
     
         17 . The method according to  claim 16 , where the sintered body has a grain size of 200 nm or less and a degree of compaction of 95% or higher. 
     
     
         18 . A method for producing a sintered body using a nano-sized metal powder, comprising the steps of:
 preparing a nano-sized metal powder feedstock prepared by the method according to  claim 7 ;   molding the nano-sized metal powder feedstock into a desired shape;   debinding the molded body; and   sintering the debound body.   
     
     
         19 . A method for producing a sintered body using a nano-sized metal powder, comprising the steps of:
 preparing a nano-sized metal powder feedstock prepared by the method according to  claim 8 ;   molding the nano-sized metal powder feedstock into a desired shape;   debinding the molded body; and   sintering the debound body.   
     
     
         20 . A method for producing a sintered body using a nano-sized metal powder, comprising the steps of:
 preparing a nano-sized metal powder feedstock prepared by the method according to  claim 12 ;   molding the nano-sized metal powder feedstock into a desired shape;   debinding the molded body; and   sintering the debound body.