逆反应烧结制备铝电解槽用氮化硅-碳化硅复合材料

采用常规的反应烧结工艺制作铝电解槽侧壁材料用Si3N4／SiC时存在不足，为此，提出应用逆反应烧结工艺进行生产性试验的设想。在制备Si3N4／SiC复合材料时，常规反应烧结是以Si和SiC为原料经氮化烧结；逆反应烧结是以Si3N4和SiC为原料，首先使Si3N4反向反应生成活性氧化物后进行烧结。结果表明：该工艺特点是新生的Si2N2O或SiO2进行活性烧结；制品具有良好的物理和化学性能。制品结构紧密，新生氧化物或亚氧化物紧密地充填在Si3N4和SiC颗粒间界，新工艺制备的砖的抗冰晶石熔体侵蚀的性能优于常规工艺烧成砖，是铝电解槽侧壁的良好材料。

REVERSE REACTION SINTERING OF Si3N4/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.