POROUS REACTIVE-SINTERED SILICON CARBIDE MATERIALS WITH NEGATIVE VOLUME EFFECTS

摘要

Microporous silicon-carbide materials are fabricated by methods of reactive sintering in reactive systems with negative volume effects. Reactions involved in carbothermic reduction of silicon oxide and the synthesis of SiC from elements are employed. Silicon carbide materials with pore dimension 0.2 mum are obtained in preliminary pulverization of a mixture of silicon and graphite and sintering of the compacts in argon for 15 min. Estimates of the selectivity of the resulting membrane materials to toxic impurities in waste water are presented. Silicon carbide materials sintered in liquid phase from SiC powders on a CaSiO_3 binder are tested as potential substrates for fabrication of two-layer membranes. The absence of shrinkage and minimal shrinkage, respectively, of reactive-sintered and liquid-phase sintered materials have made it possible to produce two-layer samples provided with a substrate which is strongly bound to a selective layer synthesized from a mixture of silicon and graphite.