硅粉加入量对碳纤维增强铝碳耐火材料显微结构和强度的影响

Effect of Silicon Powder Content on Microstructure and Strength of Carbon Fiber Reinforced Alumina-Carbon Refractories

以电熔白刚玉、石墨、硅粉和碳纤维为主要原料,通过固定刚玉细粉和硅粉总含量(29%),改变硅粉加入量(0~20%)制得了六组碳纤维增强铝碳耐火材料。采用XRD、SEM及EDS等研究了硅粉加入量对不同温度处理后材料物相组成、显微结构及强度的影响。结果表明:(1)220℃热处理后,硅粉含量低于8%时,抗折耐压强度变化不大;硅粉的含量高于8%时,抗折与耐压强度均降低。(2)1400℃热处理后,当硅粉含量从0增加到8%时,耐压强度与抗折强度均得到明显改善。而当硅粉量进一步增加时,试样出现裂纹,强度显著下降。(3)综合考虑,硅粉的最佳加入量为8%,此时经220℃、1400℃热处理后材料具有最好的抗折强度及耐压强度。

Carbon fiber reinforced alumina-carbon refractories containing different silicon powder content （0-20%） were prepared by using fused white corundum as aggregate, and graphite, carbon fiber, corundum powder as matrix, and silicon powder as additive, fixed total mass percentage （29%） of white corundum powder and silicon powder. The phase compositions, microstructures and strengths of samples heated at different temperature were analyzed by the XRD, SEM＇and EDS. The results demonstrate that： （ 1 ） When the heating temperature is 220 ℃, with an increase of silicon powder content from 0 to 8%, the compressive and flexural strengths change little; whereas, with an increase of silicon powder content from 8% to 20%, the compression and flexural strengths are reduced. （2）When the heating temperature is 1400 ℃, with an increase of silicon powder content from 0 to 8%, the compressive and flexural strengths are significantly improved; with a further increase of silicon powder content, some cracks appeare on the surface of the samples, and then the strength decrease sharply. （3） The most appropriate mode is a sample containing 8% silicon powder, which has optimal performance after heated at 220 ℃ and 1400 ℃.