以活性α-Al2O3和轻质碳酸钙为原料,在1 400℃空气气氛中反应烧结合成了六铝酸钙(CA6),并研究了保温时间(分别为30、60、120、180和240 min)对合成CA6的物相组成、物理性能和显微结构的影响.结果表明:在1 400℃下,适当延长保温时间可以提高CA6的生成量,保温120 min之前已迅速合成CA6,完全合成CA6需保温240 min以上;随着保温时间的延长,试样的体积密度先减小后增加,其显气孔率和常温耐压强度则相反,线膨胀逐渐增大,试样中CA6片状晶体形貌更加明显;试样中的CA6片状晶体在1 400℃保温30 min时已开始生成,生长和发育主要是在保温180 min之前.%Calcium hexaluminate (CA6) was synthesized at 1 400 ℃ under air atmosphere by reaction sintering from light-weight calcium carbonate and activated α-AI2O3. The influence of soaking times (30,60,120, 180 and 240 min) on the phase composition, microstructure and physical properties of calcium hexaluminate was investigated. The results show that: (1) prolonging soaking time appropriately can increase the formation amount of CA6;CA6 has been synthesized rapidly before soaking for 120 min,while the complete synthesis of CA6 needs soaking time over 240 min; (2) prolonging the soaking time,the volume density of specimens first decreases and then increases, the apparent porosity and cold crushing strength are the opposite,the expansion rate in dimensions increases gradually,and the planar morphology of CA6 generated in specimens is more obvious;(3)the planar CA6 crystal grains start to form when soaking for 30 min at 1 400 ℃.and grow and develop primarily before soaking for 180 min.
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