掺杂MgO和La_2O_3对Al_2O_3陶瓷性能的影响

Effect of MgO and La_2O_3 doping on properties of Al_2O_3 ceramics

以高纯硫酸铝氨分解的无定形Al2O3为原料,MgO、La2O3为烧结助剂,在N2气氛下热压烧结制备Al2O3陶瓷。研究了MgO和La2O3掺杂量对所制Al2O3陶瓷的相组成、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:随着MgO或La2O3掺杂量的增加,Al2O3晶粒尺寸均逐渐减小而抗弯强度逐渐升高,热导率和介质损耗则分别呈现为先增大后减小和先减小后增大的变化规律。当MgO或La2O3掺杂量均为质量分数2.0%时,Al2O3陶瓷呈现较佳的综合性能:抗弯强度均达518MPa以上,热导率均在30.1W·m-1·K-1左右,介质损耗分别低至4.60×10-4和6.70×10-4。

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,La2O3 as additives.The effects of MgO and La2O3 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 or La2O3,the average grain size decreases while the bending strength increases gradually.The thermal conductivity increases and then decreases,and the case is on the contrary for dielectric loss.When the mass fraction of MgO or La2O3 is 2.0%,the materials show the superior comprehensive properties：bending strength of above 518 MPa,thermal conductivity of about 30.1 W·m-1·K-1,and the lowest dielectric loss of 4.60×10-4 and 6.70×10-4,respectively.