Method of producing high density silicon carbide product

Abstract

Disclosure is made of a high-density, high-strength silicon carbide ceramic material that is produced using a silicon carbide powder containing boron or boron-containing compound as a densification additive by the utilization of boron in the sintering atmosphere.

What is claimed is: 
     
       1. A method of sintering silicon carbide powders containing boron or boron-containing compounds as densification aids to produce a high density silicon carbide ceramic material which comprises the step of sintering such powders in an atmosphere containing boron, wherein the partial pressure of boron in the sintering atmosphere is equal to or greater than the equilibrium vapor pressure of the boron in the silicon carbide powder during sintering of said powder.[...]..Iadd., said partial pressure of boron in the sintering atmosphere being provided by boron from a boron-containing slurry or solution applied to the interior of the sintering chamber prior to sintering, or by the addition of a boron-containing gas into the chamber during sintering .Iaddend.. 
     
     
       2. The method of claim 1 wherein the silicon carbide containing powders include boron in an amount between about 0.1 and about 5.0 percent by weight. 
     
     
       3. The method of claim 1 wherein the atmosphere containing boron includes an inert gas. 
     
     
       4. The method of claim 3 wherein the inert gas is nitrogen. 
     
     
       5. The method of claim 3 wherein the inert gas is argon. 
     
     
       6. The method of claim 3 wherein the inert gas is helium. 
     
     
       7. The method of claim 1 wherein the boron in the atmosphere is introduced as boron.[.chloride.]. .Iadd.trichloride..Iaddend. 
     
     
       8. The method of claim 1 wherein the boron in the atmosphere is introduced as boron carbide.