Support member for high-temperature heat-treated metal molding object and process for production thereof

Abstract

A carbonaceous support member for a high-temperature heat-treated metal molding object, particularly a setter for heat-treatment in powder metallurgy, is formed as a carbon-ceramic composite shaped product having a bulk density of 1.2-1.6 g/ml and including a carbonaceous matrix and 3-20 wt. % of ceramic particles which are uniformly dispersed in the carbonaceous matrix and partly exposed to the surface of the composite. The support member can effectively prevent carburization of a metal molding object supported thereby during the heat-treatment without causing a problem of peeling of coating layer as encountered in a ceramic-coated support member. The support member may be prepared by compression molding of a powdery mixture of a fine carbon precursor and ceramic particles, followed by heating at 1000-2000° C. to carbonize the fine carbon precursor.

1 - 7 . (canceled) 
     
     
         8 . A process for producing a metal molding object, comprising
 providing a support member in a form of a carbon-ceramic composite shaped product comprising a carbonaceous matrix and 3-20 wt. % of ceramic particles uniformly dispersed in the carbonaceous matrix and partly exposed to a surface of the carbon-ceramic composite shaped product, said carbon-ceramic composite shaped product having a bulk density of 1.2-1.6 g/ml;   forming a shaped metal powder compact;   placing the shaped metal powder compact in contact with the partly exposed ceramic particles of the support member;   heating the shaped metal powder compact together with the support member at a temperature of 800° C. or higher in a reducing or non-oxidizing atmosphere to sinter the metal powder compact; and   cooling and recovering the sintered metal powder compact as the metal molding object in separation from the support member.   
     
     
         9 . The process according to  claim 8 , wherein the ceramic particles have a primary particle size of 50-500 μm. 
     
     
         10 . The process according to  claim 8 , wherein the ceramic particles comprise fused alumina having an alumina purity of at least 90 wt. %. 
     
     
         11 . The process according to  claim 8 , wherein the metal molding object is a steel-made mechanical part. 
     
     
         12 . The process according to  claim 8 , wherein the support member is provided by molding a mixture of a fine carbon precursor and ceramic particles under pressure to form a compact, and heat-treating the compact at a temperature of 1000-2000° C. to carbonize the carbon precursor. 
     
     
         13 . The process according to  claim 12 , wherein the mixture of the fine carbon precursor and the ceramic particles is formed by dispersively attaching the ceramic particle together with a thermosetting resin onto the surface of the fine carbon precursor and then molded under pressure. 
     
     
         14 . The process according to  claim 13 , wherein the thermosetting resin comprises a liquid thermosetting resin. 
     
     
         15 . The process according to  claim 14 , wherein the fine carbon precursor is first, coated with the liquid thermosetting resin, and then a solid thermosetting resin and the ceramic particles are attached to the fine carbon precursor, followed by the molding under pressure.