TiO2烧结助剂对纳米η-Al2 O3制备Al2 O3-Cr2 O3固溶体的影响研究

以纳米η-Al₂O₃粉和工业铬绿为原料,以摩尔比1:1配比制备Al₂O₃-Cr₂O₃固溶体,以TiO₂为烧结助剂,在还原气氛下经1400 ℃、1500 ℃和1600 ℃固相烧结.研究了TiO₂的加入对纳米η-Al₂O₃制备Al₂O₃-Cr₂O₃固溶体的致密度、线收缩率、相组成、晶胞参数、互扩散程度和微观结构的影响.结果表明:TiO₂的加入能促进Al₂O₃-Cr₂O₃固溶体的致密化;当温度为1600 ℃,TiO₂的添加量为2wt;时,试样的体积密度最大为4.57 g·cm^-3,线收缩率为19.8;;TiO₂的加入能使Al₂O₃-Cr₂O₃固溶体中Al³⁺和Cr³⁺的互扩散程度增加;微观结构表明,TiO₂的加入能使Al₂O₃-Cr₂O₃固溶体晶粒之间结合更紧密,实验温度范围内,随着TiO₂添加量的增加晶粒从沿晶断裂向穿晶断裂转变,只在晶间和晶内存在极少量气孔,当温度为1600 ℃,TiO₂的添加量为2wt;时,晶粒大小较均匀,平均晶粒尺寸约10μm.

Effect of TiO2 Sintering Aid on the Al2O3-Cr2O3 Solid Solution Prepared from Nano-η-Al2O3

Al2O3-Cr2O3 solid solution was prepared using nano-η-Al2O3 powder and industrial chrome green as raw materials in a molar ratio of 1:1.The solid phase sintering was carried out at 1400℃,1500℃ and 1600℃ in a reducing atmosphere using TiO2 as sintering aid.The effects of TiO2 addition on the density,linear shrinkage,phase composition,unit cell parameters,degree of interdiffusion and microstructure of Al2O3-Cr2O3 solid solution prepared from nano-η-Al2O3 were studied.The results show that the addition of TiO 2 can promote the densification of Al2O3-Cr2O3 solid solution.When the temperature is 1600℃and the addition amount of TiO2 is 2wt%,the maximum bulk density of the sample is 4.57 g·cm^-3,and the linear shrinkage is 19.8%;the addition of TiO2 can increase the degree of interdiffusion of Al^3+ and Cr^3+ in Al2O3-Cr2O3 solid solution;the microstructure shows that TiO 2 can make the grains of Al2O3-Cr2O3 solid solution combine more closely.The addition of TiO2 increases the grain transition from crystal fracture to transgranular fracture,and there are only a small number of pores between and within the crystal,within the experimental temperature range.When the temperature is 1600℃ and the additive amount of TiO2 is 2wt%,the grain size is relatively uniform,with an average grain size of about 10μm.