添加Y_20_3的ZrSi0_4/α-A1_20_3混合粉体的反应烧结

REACTION SINTERING OF ZrSiO_4/α- A1_2O_3 MIXED POWDERS WITH Y_2O_3 ADDITION

采用XRD和TEM等技术研究了添加Y2O3的ZrsiO4/α-A12O3混合粉体的反应烧结过程,包括坯体的致密化、Y2O3的存在方式及相组成。结果表明,Y2O3的引入加快了坯体的致密化,促进了ZrSiO4的分解和莫来石的形成。添加的Y2O3,一部分存在于晶界玻璃相中,一部分进入ZrO2晶格中使之以四方相形式存在。随着Y2O3添加量的增加,试样中四方相ZrO2相对含量增加;当Y2O3/(Y2O3+ZrO2)的摩尔比达到5％时,立方相ZrO2开始出现。

Mullite-zirconia multiphase ceramics were prepared starting from ZrSiO4/α-Al2O3 mixtures. The effects of the Y2O3 addition on the reaction sintering of ZrSiO4/α-Al2O3 mixed powders were investigated using XRD and TEM techniques. It is found that the Y2O3 addition can greatly accelerate the densification as well as the reaction (i.e., ZrSiO4 dissociation and mullization). The Y2O3 added was detected in both the glassy phase and the ZrO2 crystal lattice. The Y2O3 in the ZrO2 crystal lattice resulted in the formation of t-ZrO2 or c-ZrO2, which provides a possibility for producing tough reaction-sintered ZrO2/mullite composites using the martensitic transformation of ZrO2.