Al_2O_3和TiO_2添加量对共沉淀法制备MgO基陶瓷性能的影响

Effect of Al_2O_3 and TiO_2 Addition Amount on Properties of MgO-based Ceramics by Coprecipitation Method

采用共沉淀法分别制备Al_2O_3和TiO_2前驱体包覆MgO颗粒,并在1 450℃保温2h得到MgO基陶瓷,研究了Al_2O_3和TiO_2添加量对陶瓷物相组成、烧结性能和抗热震性能的影响.结果表明:添加Al_2O_3后,陶瓷的主要物相为方镁石相和MgAl_2O_4相,随Al_2O_3添加量的增加,MgAl_2O_4相含量增多,线收缩率和热震次数均先增后降,体积密度则增大;添加TiO_2后,陶瓷的主要物相为方镁石相、Mg_2TiO_4相和MgTiO_3相,随TiO_2添加量的增加,Mg_2TiO_4和MgTiO_3相含量增多,线收缩率和体积密度均先增后降,热震次数则先增加后保持稳定;当Al_2O_3和TiO_2的质量分数分别为6%,4%时,陶瓷的烧结性能和抗热震性能均最佳.

MgO particles coated with Al2O3 and TiO2 precursors,respectively, were prepared by coprecipitation method and sintered at 1 450 ℃ for 2 h,and then the MgO-based ceramics were obtained.The effects of the addition amount of Al2O3 and TiO2 on the phase composition,sintering performance and thermal shock resistance of the ceramics were investigated.The results show that the ceramics added with Al2O3 mainly consisted of periclase and MgAl2O4 phases.With increasing Al2O3 addition amount,the MgAl2O4 phase content increased,the linear shrinkage rate and the number of thermal shock cycles first increased and then decreased,and the bulk density increased.The ceramics added with TiO2 was mainly composed of periclase,Mg2TiO4 and MgTiO3 phases. With increasing TiO2 addition amount,the content of Mg2TiO4 phase and MgTiO3 phase increased,the linear shrinkage rate and bulk density first increased and then decreased,and the number of thermal shock cycles first increased and then remained stable.When the mass fractions of Al2O3 and TiO2 were 6%,4%,respectively,both the sintering performance and thermal shock resistance of the ceramics were the best.