摘要
近年来,由于α′-sialon的高硬度和良好的抗热震性,使α′和α′-β′复相sialon陶瓷的研究引人注目。对α′-sialon平面相关系的测定已经表明:α′-sialon的单相区起始于纯氮化物一端向氧化铝方向延伸,在α′-simon和β′-sialon之间存有一个α′-β′两相区。这个两相区提供了制备两相陶瓷的可能性。由于α′和β′组成的差别甚微,因此在烧成过程中,当加有适当的添加剂时,α′和β′之间的相变很容易发生。故在制备α′-sialon划α′-β′-sialon陶瓷时,控制相变极为重要,为此有必要了解它们的反应机理。 本文描述了在不同烧成环境下α′和α′-β′-sialon的反应机理,所采用的组成是含Y的α′-sialon,并分别添加和不加La_2O_3作为助烧结剂。本文还着重研究了烧成环境对α′和β′相互转变的影响,以及La_2O_3对致密化和α′-sialon形成的作用。
Recently more and more attention has been paid to α′ and α′-β′composite sislon ceramics because of the hardness and the better thermal shock properties of α′-sialon materials. Phase relationships determined in the α′ plane show that α′-sialon extends from pure nitrides side towards alumina side, and there exists a fairly large region of α′-sialon in equilibrium with β′-sialon, thus providing the possibility to fabricate α′-β′ composite sialon ceramics. Because of the small difference in compositions between α′ and 1β′ sialons, transformation between α′ and β′ occurs very rapidly at firing temperatures in the presence of an appropriate grain-boundary liquid phase. Therefore, control of the transformation is of importance for fabricating both α′ and α′-β′ composite sialons and it is necessary to study its reaction mechanisms.This paper describes the reaction sequence under different firing circumstances of α′ and α′-β′ sialon with Y as a 'modifying' cation, doped with or without La_2O_3 as densifying additive respectively. The effect of firing conditions on transformation between α′ and β′, and the role of La_2O_3 on densification as well as the formation of α′ sialon are discussed.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
1989年第1期1-7,共7页
Journal of The Chinese Ceramic Society
关键词
Sialon形成
相变
烧成条件
陶瓷
formation of sialon
phase relationships
effect of firing condition
