MgO-Y_2O_3对热压烧结Al_2O_3性能的影响

以高纯的硫酸铝氨分解的无定形Al2O3为原料,MgO-Y2O3为烧结助剂,在N2气氛下热压烧结制备Al2O3陶瓷。研究了烧结助剂掺量对Al2O3材料的相组成、显微结构、烧结性能、力学性能、热导率和介电性能的影响。结果表明:所制Al2O3陶瓷具有细晶的显微结构特征和超高的抗弯强度。随着MgO-Y2O3掺量的增加,晶粒尺寸、抗弯强度和热导率先增大后减小,而介电损耗则呈现先减小后增大的变化规律。当MgO和Y2O3掺量均为质量分数2%时,Al2O3陶瓷呈现为较佳的综合性能:抗弯强度达最大值为603 MPa,热导率为36.47 W.m–1.K–1,介电损耗低至6.32×10–4。

Effect of MgO-Y2O3 on properties of Al2O3 materials prepared by hot-pressing sintering

Al2O3 ceramics were prepared by hot-pressing sintering in N2 atmosphere,with amorphous Al2O3 decomposed from high-purity aluminum ammonium sulfate as raw material and MgO-Y2O3 as additives.The effects of sintering additives content on the phase formation,microstructure,sintering properties,mechanical properties,thermal conductivity and dielectric properties of the Al2O3 ceramics were investigated.The results show that the Al2O3 ceramics exhibite fine-grained microstructure and consequently excellent bending strength,with the increase of content of MgO-Y2O3,the average grain size,bending strength and the thermal conductivity increase first,and then decrease,and the case is on the contrary for dielectric loss.When the contents of MgO-Y2O3 both are 2%(mass fraction),the materials show superior comprehensive properties: the bending strength of the sample is 603 MPa,which is reached to the maximun,thermal conductivity of 36.47 W?m–1?K–1,and the lowest dielectric loss of 6.32×10–4.