REVERSE REACTION SINTERING OF Si_3N_4/SiC COMPOSITE MATERIALS FOR ALUMINIUM ELECTROBATH

The merit and mechanism of Si_3N_4 bonded SiC materials and the drawback of the traditional reaction sintering process are summarized. The assumption of reverse reaction sintering process is applied in the production for Si_3N_4/SiC materials. In preparing Si_3N_4/SiC composites, Si and SiC as raw materials are react-sintered at nitrogen atmospheres by the conventional production method; while in the reverse reaction sinter process, by using Si_3N_4 ,SiC as raw materials, the Si_3N_4 is firstly converted into reactive oxides, then react-sintered. The new sintering process is accomplished by the reactive sintering of newly formed Si_2 N_2O or SiO_2 phases. The products having excellent physical and chemical properties due to its dense structure and insitu formed oxides or sub-oxides which is full filled at the boundary between Si_3N_4 and SiC particles. The products produced by the new process having dominating property over the traditional production process. The produced Si3 N4/SiC brick is an idea material for side wall of aluminum electrolyte bath.