加入Si,Si/Al对高碳Al2O3-C材料抗热震性的影响

Effects of Si,Al/Si on Thermal Shock Resistance of High Carbon Al_2O_3-C Material

以电熔白刚玉、熔融石英(粒度≤0.5mm)为骨料,鳞片石墨(粒度≤0.15mm)、电熔白刚玉粉(粒度≤0.088mm和≤0.045mm)、Si粉(粒度≤0.074mm)、Al粉(粒度≤0.088mm)为基质,热固性酚醛树脂作结合剂,压制成25mm×25mm×125mm的试样,经200℃固化24h后,在埋炭条件下经1200℃下保温3h制成碳含量为30%的高碳Al2O3-C材料。分别用5%、10%、15%、20%的Si粉替代高碳Al2O3-C材料中的石墨研究其对试样抗热震性的影响;根据Si粉替代石墨的结果又研究了不同比例Si/Al粉(总量10%)替代石墨后对试样抗热震性的影响,并用SEM和XRD分析热震后试样的显微结构和物相组成。结果表明:(1)Si替代石墨量在5%～10%之间,试样的抗热震性基本保持不变,替代量大于10%以后试样的抗热震性下降。(2)Si/Al替代石墨量为10%时,改变Si/Al比例对试样抗热震性的影响不大。(3)适量Si,Si/Al基本保持Al2O3-C材料抗热震性的原因是原位生成非氧化物。

Al2O3-C specimens containing 30% carbon were prepared by using white alumina and fused silica（ ≤0.5 mm） as aggregate, flake graphite（≤0.15 mm） ,white alumina（ ≤0. 088 mm ands≤0.045 mm） ,Si（≤0. 074 mm） ,Al（≤0. 088 ram）as matrix,and phenolic resin as binder. The specimens with size of 125 mm ×25 mm × 125 mm were formed by compaction and cured at 200℃ for 24 h,then were fired with carbon embedding at 1200℃ for 3 h. The effects of replacing carbon with Si on thermal shock resistance of the specimens had been studied by substituting graphite with 5%, 10%, 15% and 20% Si respectively;Based on the above results,the effects of different ratios of Al/Si with total amount of 10% on thermal shock resistance（TSR） of the specimens had been investigated. The microstructure and phase comcompositions of specimens after firing were analyzed When 5%-10% graphite is replaced by Si, TSR of the resistance of the specimens decreases when Si addition is by SEM and XRD. The results show that：（1） specimens keeps the same. But thermal shock more than 10%. （2） Chanze in the ratio of Al/Si （with total 10% ） has little influence on TSR of specimens. （3） Contribution of Si and Si/Al to thermal shock resistance of Al2O3-C material is due to non-oxide formed in situ.