碳化硅晶须制备微孔陶瓷

Preparation of Microporous Ceramics from Silicon Carbide Whiskers

介绍一种制备碳化硅微孔陶瓷的新方法。以碳化硅晶须为主要原料,不添加任何造孔剂,采用传统的烧结工艺,在1700℃下制备出孔隙率高于56%、平均孔径为3.8μm、弯曲强度为158 MPa的碳化硅微孔陶瓷,并研究了制备工艺对制品性能的影响。研究结果表明:微孔的形成机理主要是晶须之间的架桥作用;通过调节碳化硅晶须的长径比、烧结助剂用量、烧结温度等条件,可以有效地控制微孔陶瓷孔隙率的高低、孔径的大小及其力学性能。

Microporous ceramics were prepared from silicon carbide whiskers without pore-forming material. The microporous ceramics with apparent porosity of over 56%, average pore diameter of 3.8 μm and flexural strength of 158 MPa were obtained using the conventional sintering process at the temperature of 1700 ℃. The relationship between the processing technique and properties of the products was a/so studied. The microstructure, porosity and strength of the microporous ceramics were tested, while the preparation parameters were discussed. The pores were formed from bridging of the silicon carbide whiskers. The porosity, the pore size and the mechanics properties of the microporous ceramics could be controlled by adjusting the parameters including the aspect ratio of whiskers, the quantities of the sintering agents and the sintering temperature.