β-SiC production by reacting silica gel with hydrocarbon gas

A novel synthesis process, developed for producing high purity, submicron, non-agglomerated and low cost beta -SiC powders. The process is based on carbothermal reduction reaction of a novel coated precursor. The precursor is derived from a silica gel and a hydrocarbon gas and provides high contact area between reactants. This yields a better distribution of carbon within the silica gel and results in a more complete reaction and a purer product. The powders produced in this process have a low oxygen content (less than 0.8 wt.%), very fine particle size (0.1-0.3 mum), narrow particle size distribution, non-agglomerated and are low cost. The sintering tests demonstrated that these powders can be pressureless-sintered to near theoretical density at about 2100 degreesC in an inert atmosphere. No decarburization and no acid purification process was required before sintering. (C) 2001 Kluwer Academic Publishers.