碳化硅-莫来石-氧化锆复相材料的制备

Preparation of SiC-mullite-zirconia multiphase material

采用埋碳烧结工艺,以纳米η-Al_(2)O_(3)粉为合成莫来石结合相的铝源,硅灰为硅源,制备出了性能优良的莫来石结合碳化硅-氧化锆复相材料。研究了烧成温度对复相材料的物理性能、物相组成和微观结构的影响,分析了原料的综合热。结果表明:SiC氧化生成的SiO_(2)活性高,优先在996.5℃下与过渡相η-Al_(2)O_(3)发生固相反应形成莫来石;试样在1600℃时综合性能最佳,体积密度达到2.82g/cm^(3),显气孔率为3.2%,常温抗折强度达到143.2MPa,氧化增重仅为0.65%;ZrO_(2)煅烧后失稳由c-ZrO_(2)转变为m-ZrO_(2),并均匀分布于试样中;莫来石晶体发育良好,与碳化硅间结合紧密。

The chromium oxide sintering process is applied to produce the SiC-mullite-zirconia multiphase material featuring excellent performance,with nano-η-Al_(2)O_(3)powder taken as the aluminum source and micro-silica as the silicon source to synthesize the associative phase of mullite.With the experiment,the authors probe into the influence of firing temperature exerted on the physical property,phase composition and micro-structure of a multiphase material,and conduct comprehensive thermal analysis of the raw materials.The results show that the SiO_(2) generated by SiC oxidation is highly active so that it starts to react with theη-Al_(2)O_(3) in the transient phase under 996.5℃,forming solid mullite;the samples boast the best overall performance under 1600℃,with their bulk density reaching 2.82 g/cm^(3),apparent porosity 3.2%,flexural strength 143.2 MPa at room temperature,while oxidation mass gain 0.65%only;the calcined ZrO_(2) losses its stability,transforms from c-ZrO2 to m-ZrO_(2),and evenly distributed in the samples;the mullite crystallizes well and bonds tightly with SiC.