纳米添加剂对99氧化铝瓷结构和性能的影响

Effects of Nano-Additives on the Structure and Properties of 99% Alumina Ceramics

以高纯度超细α-Al_2O_3粉体为原料,采用镁、铬、铜的硝酸盐溶液引入纳米级添加剂,常压烧结制备99氧化铝瓷。利用SEM等测试技术对比研究了纳米添加剂和微米级氧化物添加剂对烧结温度、显微结构及抗弯强度的影响。结果表明,以硝酸盐溶液形式引入添加剂,可使添加剂以纳米级金属氧化物形式均匀分散于坯体中,具有较高的分散度和反应活性。在烧成过程中纳米添加剂对降低烧结温度和抑制晶粒长大的作用均优于微米级添加剂,并且相应烧结体具有更好的致密度和抗弯强度。

99% alumina ceramics were sintered from the high-purity and superfine α-Al2O3 powders by the normal press sintering with the addition of nitrates of magnesium, chromium and copper as the nanometer additives. The influences of the nanometer additives on the sintering temperature, microstructure and the bending strength of the sintered alumina ceramics were investigated by SEM and other test methods in comparison with the micron oxide additives. Results showed that introducing the additives in the form of their nitrate provided well-dispersed oxides at the nanometer scales in the sintered bodies because of their being highly dispersed and high activity. Therefore, the nan＇ometer additives performed better than the micron additives in reducing the sintering temperature and inhibiting the abnormal grain growth. As a result, the sintered alumina ceramics from the nano additives had a higher density and exhibited improved bending strength than those made from micron additives.