高岭土对多孔Si_3N_4陶瓷常压烧结的影响

Influence of kaolin on Pressureless Sintering of Porous Si_3N_4 Ceramics

以α-Si3N4和高岭土为原料,采用常压烧结制备出多孔Si3N4陶瓷材料。研究了高岭土的加入量对多孔Si3N4陶瓷相组成,显微结构和力学性能的影响。采用阿基米德法和三点弯曲法测试了材料的密度、气孔率及抗弯强度,并用XRD和SEM对相组成和显微结构进行了研究。结果表明:所制备材料的主晶相为β-Si3N4,微观结构是由棒状颗粒互相搭接组成。随着高岭土含量的增多,其气孔率减小,密度增加。添加20%的高岭土所得多孔Si3N4陶瓷的微观结构及抗弯强度较佳。

Porous Si3N4 ceramics were prepared with a-Si3N4 and kaolin powder by pressureless sintering technology. The density, porosity and flexural strength were tested by the methods of Archimedes and three-point bending measurement, and microstructures and phase compositions of Si3N4 ceramics were studied by XRD and SEM. The results indicated that the density increased with the decrease of the porosity. Adding 20 % kaolin in the raw silicon powder, porous Si3N4 ceramics were obtained with good microstructure and flexural strength.