Compressive Sintering Apparatus Comprising Protected Opposing Rams

Abstract

A compressive sintering system is described that comprises a die set and a vacuum chamber into which the die set is placed. The die set comprises a die casing and opposing rams forming a die cavity loaded with material to be sintered and is configured to compress the material during sintering. At least one of the opposing rams comprises a surface protection layer, such as a faceplate, in contact with the material to be sintered.

What is claimed is: 
     
         1 . A compressive sintering apparatus comprising
 a) a die set comprising a die casing and opposing rams forming a die cavity loaded with material to be sintered, the die set configured to compress the material during sintering; and   b) a vacuum chamber into which the die set is placed,   
       wherein at least one of the opposing rams comprises a surface protection layer in contact with the material to be sintered. 
     
     
         2 . The compressive sintering apparatus of  claim 1 , wherein the die set comprises an outer die casing, an upper ram, and a lower ram, and wherein both the upper ram and the lower ram comprise the surface protection layer. 
     
     
         3 . The compressive sintering apparatus of  claim 1 , wherein the surface protection layer has a thickness of from about 0.1 inches to about 2 inches. 
     
     
         4 . The compressive sintering apparatus of  claim 3 , wherein the thickness of the surface protection layer is from about 0.2 inches to about 1 inch. 
     
     
         5 . The compressive sintering apparatus of  claim 4 , wherein the thickness of the surface protection layer is from about 0.25 inches to about 0.75 inches. 
     
     
         6 . The compressive sintering apparatus of  claim 1 , wherein the surface protection layer is a coating applied to the ram. 
     
     
         7 . The compressive sintering apparatus of  claim 1 , wherein the surface protection layer is a faceplate attachable to the ram. 
     
     
         8 . The compressive sintering apparatus of  claim 1 , wherein the surface protection layer is an end cap attachable to the ram. 
     
     
         9 . The compressive sintering apparatus of  claim 1 , wherein the surface protection layer is replaceable. 
     
     
         10 . The compressive sintering apparatus of  claim 1 , wherein the surface protection layer comprises a carbon-carbon composite. 
     
     
         11 . The compressive sintering apparatus of  claim 11 , wherein the opposing rams comprise a steel. 
     
     
         12 . The compressive sintering apparatus of  claim 1 , wherein the compressive sintering apparatus is a spark plasma sintering apparatus or a direct current sintering apparatus. 
     
     
         13 . A die set for a compressive sintering apparatus, the die set comprising a die casing and opposing rams forming a die cavity, wherein the die set is configured to compress material to be sintered within the die cavity during sintering and wherein at least one of the opposing rams comprises a surface protection layer in contact with the material to be sintered. 
     
     
         14 . A method of forming a sintered product comprising, in any order, the steps:
 i) loading a material to be sintered into a die cavity of a die set comprising a die casing and opposing rams configured to compress the material;   ii) placing the die set into a vacuum chamber of a sintering apparatus; and   iii) compressively sintering the material in the die cavity to form the sintered product, wherein at least one of the opposing rams comprises a surface protection layer in contact with the material to be sintered.