PROCESS FOR PREPARING SILICON CARBIDE

摘要

A process for preparing silicon carbide by carbothermal reduction involv es rapidly heating a particulate reactive mixture of a silica source and a carb on source to form a product which shows improved uniformity of crystal size. The produ ct of this process can be used to form a densified part. The process comprises: passing a particulate reactive mixture (24) of a silica source and a carbon source int o a reactor having (a) a reactant transport member (6), the reactant transport member having a wall defining a hollow conduit, the wall having a cooling means and being further characterized as having a concentric inner wall defining an inner annular space (20), the inner annular space having an inlet and being open at the bottom such th at a gas can be flowed therethrough; (b) a reactor chamber (16), the reactor chamber having a wall (26), defining a reaction zone (28), the chamber being in fluid connection with the reactant transport member; (c) a heating means (40), the heating means being suitable for heating the particulate reactive mixture in the reaction zone; and (d) a cooling chamber (42), the cooling chamber having a wall (48) defining a cooling zone (44), the wall having a cooling means, the cooling chamber being in flu id connection with the reactor chamber; the temperatures of thereactant transport member, reactor chamber, and cooling chamber being independently controllabl e; such that the particulate reactive mixture can be fed continuously through the reactant transport member into the reactor zone and than into the cooling zone.