Y_2O_3对红柱石增强莫来石陶瓷性能影响

Effect of Y_2O_3 on Property of Mullite Ceramic Enhanced by Andalusite

为制备高致密的红柱石增强莫来石陶瓷,本工作以天然红柱石和活性氧化铝为原料,利用细磨、等静压、引入Y_2O_3添加剂工艺,通过固相反应烧结制备红柱石增强莫来石质陶瓷匣钵。研究了在不同成型方式条件下,Y3+掺杂对反应烧结制备红柱石增强莫来石质陶瓷的烧结性能和热震稳定性的影响,同时借助XRD、SEM及相关软件对其烧后试样的矿物相组成、晶胞常数和显微结构进行分析和计算。结果表明:通过掺杂一定量Y3+,利用等静压成型,经1500℃保温2 h烧成,可以制备出具有高致密度的红柱石增强莫来石质陶瓷。随着Y_2O_3加入量增加,红柱石增强莫来石陶瓷烧结性能明显改善,热震稳定性稍有降低,而当Y_2O_3加入量大于6%,部分Y_2O_3与组成中SiO_2形成第二相Y_2Si_2O_4,在一定程度上又改善了莫来石陶瓷的热震稳定性。当Y_2O_3加入量大于4%时,等静压成型和干压成型莫来石陶瓷烧后试样相对密度大于95%。Y_2O_3加入量大于6%时,莫来石固溶体类型由Al4.52Si1.48O9.74转变为Al2.3Si7.04O4.85。

Mullite ceramic enhanced by andalusite was prepared by solid reaction of natural andalusite and active alumina as raw materials, using the process of finely grinding, isostatic pressing and introducing Y_2O_3. The effects of Y3+ on sintering and thermal shock of mullite ceramic sagger shaped by different methods were studied. At the same time, the crystalline phase composition, lattice parameters and microstructure of ceramics were analyzed by XRD, SEM and related software. The results indicate that the high-density mullite ceramic enhanced by andalusite, can be prepared by doping Y_2O_3 through the process of isostatic pressing and sintering at 1500 ℃ for 2 h. The sintering property of mullite ceramic enhanced by andalusite could be improved significantly with increasing Y_2O_3 addition and the thermal shock resistance of the mullite ceramic would be reduced slightly. When Y_2O_3 addition is more than 6%, the second phase of Y_2Si_2O_4 would be formed with the original Si O2 and excessive Y_2O_3 and the thermal shock resistance of mullite ceramic would be improved to some extent. The sintered specimens, shaped by isostatic and dry pressing, posses more than 95% relative bulk density of when more than 4% Y_2O_3 is added. The transition from Al4.52Si1.48O9.74 to Al2.3Si7.04O4.85 would occur for mullite solid solution when more than 6% Y_2O_3 is added.