逆反应烧结制备铝电解槽用氮化硅—碳化硅复合材料

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

采用常规的反应烧结工艺制作铝电解槽侧壁材料用Si_3N_4/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Si_3N_4/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Si_3N_4和SiC为原料，首先使Si_3N_4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Si_2N_2O或SiO_2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Si_3N_4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。

The merit and mechanism of Si3N4 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 Si3N4/SiC materials. In preparing Si3N4/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 Si3N4, SiC as raw materials, the Si3N4 is firstly converted into reactive oxides, then react-sintered. The new sintering process is accomplished by the reactive sintering of newly formed Si2N2O or SiO2 phases. The products having excellent physical and chemical properties due to its dense structure and in-situ formed oxides or sub-oxides which is full filled at the boundary between Si3N4 and SiC particles. The products produced by the new process having dominating property over the traditional production process. The produced Si3N4/SiC brick is an idea material for side wall of aluminum electrolyte bath.