Process for producing a dense, self-sintered silicon carbide/carbon-graphite composite

摘要

A process for producing a dense, self-sintered silicon carbide/carbon-graphite composite material is disclosed. The process for producing the composite material comprises the steps of:(a) providing a particulate mixture comprising:(i) carbon-bonded graphite of between 2 and 30 percent by weight of the mixture, the carbon-bonded graphite comprising at least 5 percent by weight carbon-precursor binder, the balance being graphite,(ii) between 1 and 10 percent by weight of a binder,(iii) between 0,1 and 15 percent of a sintering aid,(iv) between 1 and 5 percent by weight of a lubricant, and(v) the balance being silicon carbide; and(b) shaping the mixture to form a green body;(c) heating the green body in a non-oxidising atmosphere at a carbonizing temperature above 371° (700°F) to carbonize the binder; and(d) sintering the carbonized body at a temperature ranging from 1900°C to 2300°C in a substantially inert atmosphere at or below atmospheric pressure to produce a sintered body having a density of at least 80 percent of theoretical and a microstructure in which the average grain size of the carbon-graphite is larger than the average grain size of the silicon carbide.