矾土基锆刚玉对铝碳材料性能的影响

Effect of bauxite-based fused corundum-zirconia addition on properties of Al_2O_3-C material

以电熔白刚玉、熔融石英(粒度≤0.5 mm)为骨料,鳞片石墨(粒度≤0.15 mm)、电熔白刚玉粉(粒度≤0.088 mm和≤0.045 mm)、矾土基锆刚玉(粒度≤0.088 mm)为基质,热固性酚醛树脂作结合剂,压制成125 mm×25 mm×25 mm的试样,经200℃固化24 h后,在埋炭条件下经1 200℃保温2.5 h烧制成碳质量分数为28%的铝碳材料。研究了用质量分数分别为3%、6%、9%、12%的矾土基锆刚玉等量替代铝碳材料中的石墨对其常温物理性能、热态强度和抗氧化性的影响,并采用SEM分析烧成后试样的显微结构。结果表明:(1)随着矾土基锆刚玉加入量的增加,试样的显气孔率下降,体积密度增加,常温和高温抗折强度升高,抗氧化能力增强;(2)矾土基锆刚玉的加入量超过6%,试样的抗热震性显著下降;矾土基锆刚玉取代碳的量不宜超过6%。

The Al2O3-C material with 28 wt% carbon was prepared using white fused alumina and fused quartz（particle size is ≤0.5 mm） as aggregate,flake graphite （particle size is ≤0.15 mm）,white fused alumina（particle size is ≤0.088 mm and ≤0.045 mm）,bauxite-based fused corundum-zirconia（particle size is ≤0.088 mm） as matrix,thermosetting phenol formaldehyde resin as binder.The specimens were pressed into 125 mm×25 mm×25 mm.After 24 h curing at 200 ℃,the specimens were fired at 1 200 ℃ for 2.5 h in carbon embedded condition.The effects of bauxite-based fused corundum-zirconia on physical properties at room temperature,hot strength and oxidation resistance of the materials were studied by using bauxite-based fused corundum-zirconia（with additions of 3%,6%,9% and 12%,respectively） to substitute the same quantity of graphite in Al2O3-C material,and the microstructure of fired specimens was analyzed by SEM.The results showed that：（1）With the increase of bauxite-based fused corundum-zirconia addition,the apparent porosity of the specimen decreased,but the bulk density,modulus of rupture（at room and high temperature） and oxidation resistance increased.（2）The thermal shock resistance of the specimens decreased obviously when bauxite-based fused corundum-zirconia addition exceeded 6%;the optimum amount of bauxite-based fused corundum-zirconia addition substitution for graphite should be no more than 6%.