摘要
以工业SiC和硅铁粉为原料,二者的配料组成(质量分数)分别为90%和10%,外加2%的黄糊精为暂时结合剂,采用半干法机压成型后在氮化炉中于1380℃5 h氮化烧成制备出氮化硅铁结合SiC复合材料,在变温(常温～1400℃)氧化试验的基础上,分别在1100℃、1200℃和1300℃进行了等温氧化试验,并且分析了1300℃3 h氧化后试样的显微结构和相成分.结果表明,氮化硅铁结合SiC复合材料在1100～1300℃范围内的氧化规律为:氧化初期,试样单位面积的质量变化符合直线规律;氧化中期,近似符合二次曲线;氧化后期,符合抛物线规律.与气孔较多的内部相比,1300℃3 h氧化后试样的表面生成了一层较致密的氧化层,检测后认为,表面含有较多的SiO2,在高温下弥合了表面气孔,阻止了试样的进一步氧化.
The specimens of ferro-Si3N4 bonded SiC composites were prepared by semi-dry shaping and fired at 1380°C for 5 h in nitriding furnace using SiC (90%) and ferro-silicon powder (10%) as main starting materials and dextrin (extra 2%) as the temporary binder. Based on the varying-temperature(room temperature [similar to] 1400°C) oxidation experiment, the isothermal oxidation experiments were done at 1100°C, 1200°C and 1300°C respectively. The microstructures and phase compositions of specimens after oxidation experiment at 1300°C for 3 h were analyzed. The results indicated that the oxidation mechanism of ferro-Si3N4 bonded SiC composites during 1100-1300°C was: the mass change per unit area at initial oxidation stage was in agreement with beeline rule, in the intermediate stage in agreement with conic, and in the final oxidation period in agreement with parabola rule. Compared with the inner part which having more pores, a compact oxidized layer formed on the surface of ferro-Si3N4 bonded SiC after oxidation experiment at 1300°C for 3 h. The product of SiO2 formed protecting film at the surface of the specimens, which filled the pores and prevented the further oxidation of materials.
出处
《耐火材料》
EI
CAS
北大核心
2005年第2期94-97,共4页
Refractories
