Abstract: Al₂O₃-SiC-C materials were prepared using recycled corundum (1-3 and 3-5 mm),white fused corundum (≤1 mm),α-Al₂O₃ micropowder (≤10 μm),flake graphite (≤50 μm) and silicon carbide (≤1 mm) as main starting materials,silicon powder (≤74 μm) as the antioxidant,and thermosetting phenolic resin with a carbon residue of about 45 mass% as the binder.The effects of the zirconia corundum (AZ40,≤74 μm) addition (0,3%,6%,9% and 12%,by mass) on the structure and properties of the Al₂O₃-SiC-C materials were investigated.The fracture morphology of the samples after heat treatment was observed using a field emission scanning electron microscope,and the structure was analyzed.The results show that:(1)with the increase of the AZ40 addition,the bulk density,cold modulus of rupture,cold compressive strength,hot modulus of rupture,and the retention ratio of the cold modulus of rupture of the samples all increase first and then decrease,while the apparent porosity and oxidation index change in reverse;(2)with the AZ40 addition increasing to 12%,the sample performs lower mechanical and antioxidant properties than that without AZ40,indicating that an appropriate AZ40 addition is beneficial to improving the mechanical properties,thermal shock resistance and oxidation resistance of the Al₂O₃-SiC-C materials;(3)the sample with 3% AZ40 exhibits the best comprehensive performance.

Key words: zirconia corundum, Al₂O₃-SiC-C, strength, thermal shock resistance, oxidation resistance, microstructure

摘要： 以再生刚玉(粒度为1~3、3~5 mm)、电熔白刚玉(粒度≤1 mm)、α-Al₂O₃微粉(粒度≤10 μm)、鳞片石墨(粒度≤50 μm)、碳化硅(粒度≤1 mm)为主要原料,硅粉(粒度≤74 μm)为防氧化剂,残碳量约为45%(w)的热固性酚醛树脂为结合剂制备Al₂O₃-SiC-C材料。研究了锆刚玉(AZ40)(粒度≤74 μm)添加量(加入质量分数分别为0、3%、6%、9%、12%)对Al₂O₃-SiC-C材料结构与性能的影响,并借助场发射扫描电子显微镜观察热处理后试样的断口形貌,对其结构进行分析。结果表明:1)随着AZ40添加量的增加,试样的体积密度、常温抗折强度、耐压强度、高温抗折强度和常温抗折强度保持率均先升高后下降,显气孔率和氧化指数的变化规律则相反;2)当AZ40添加量增加至12%(w)时,试样的力学性能和抗氧化性能都低于未添加试样的,这说明在Al₂O₃-SiC-C材料中添加适量的AZ40,有利于提高材料的力学性能、抗热震性能和抗氧化性能;3)当AZ40添加量为3%(w)时,试样的综合性能最佳。

关键词: 锆刚玉, Al₂O₃-SiC-C, 强度, 抗热震性, 抗氧化性, 显微结构