烧结温度对Si_3N_4显微结构及性能的影响

Effects of Sintering Temperature on Microstructure and Performances of Micro-Porous Si_3N_4 Ceramics

文摘基于凝胶分子造孔机理,通过提高凝胶注模工艺中有机单体含量,制备微多孔氮化硅陶瓷,研究了烧结温度对Si3N4微多孔陶瓷烧结体的显微结构、强度、气孔率、孔径等方面的影响。结果表明,温度升高有利于β-Si3N4晶相的生成,烧结温度为1680℃时,氮化硅陶瓷烧结体中α-Si3N4和β-Si3N4并存,当烧结温度为1730和1 780℃时,氮化硅陶瓷烧结体的晶相全部为β-Si3N4;陶瓷烧结体的孔径均<1μm,而且孔径分布范围较窄、较均匀;随着烧结温度的提高,陶瓷烧结体的强度单调上升而气孔率下降。

Based on the principle of pore forming of gel molecule during gel-casting preparation of porous ceramics, micro-porous Si3N4 ceramics was prepared. Effects of sintering temperature on the microstructure and performances of micro-porous Si3N4 ceramics were investigated. The experimental results indicate that：the increase of sintering temperature is conducive to the formation of β -Si3N4crystal phase,α -Si3N4 and 13 -Si3N4 crystal phases coexist in sintering body at 1680℃, and only 13 -Si3N＋ crystal phase exists at 1 730℃ and 1 780℃ ;the median pore di- ameter of porous Si3N4 ceramics is less than 1 μm, and the distribution of pore diameter is narrow and uniform;with the increase of sintering temperature, porosity of Si3 N4 ceramics decreases and the flexural strength increases.