掺杂TEOS的YAG透明陶瓷相转变、烧结及微观组织

Phase transformation,sintering and microstructures of transparent YAG ceramics doping TEOS

分别添加0.3%～3.0%(质量分数)的正硅酸乙酯(TEOS)为烧结助剂,利用液相烧结合成钇铝石榴石(Y3Al5O12,YAG)透明陶瓷。结果表明:液相生成是一种动态过程,最低形成温度约为1400℃。烧结体相对密度随着烧结温度的升高而明显增大,且烧结助剂对致密化过程的促进作用与其含量有关。当w(TEOS)≤0.5%时,TEOS能够更明显地促进烧结,TEOS含量对真空烧结后烧结体内残留硅酸盐相的数量、分布和显微结构产生很大的影响。当w(TEOS)≤0.5%时,Y2Si2O7与Al2O3·SiO2(MUL)固溶于YAG晶粒内,晶界处没有残留第二相;当w(TEOS)为2%和3%时,过量的Y2Si2O7与MUL在晶界析出而成为散射源,严重损害陶瓷的光学性能。

The transparent YAG ceramics were prepared by liquid phase sintering（LPS） with 0.3%～3.0%TEOS（mass fraction） as sintering additive.The results indicate that the formation of the liquid phase is a continous course,and the initial formation temperature for the liquid phase is about 1400℃.The relative density of sintered bodies increases with increasing sintering temperature.The different enhanced densification is a result of the different additive content.The sintering process is obviously improved in the doping sample with w（TEOS） ≤0.5%.The content of TEOS has a strong inflence on the quantity and distribution of the remaining metasilicate phases and the microstructure of the vacuum-sintered bodies.When w（TEOS） ≤0.5%,Y2Si2O7 and Al2O3·SiO2（MUL） phases exist in YAG grains and the second phase at the grain boundary is not observed.When w（TEOS） are 2%and 3%,surplus Y2Si2O7 and MUL appear at the grain boundary and become the scattering source to damage the optical performance strongly.