自增韧α-sialon陶瓷的研究进展

RESEARCH PROGRESS OF SELF-REINFORCED α-SIALON CERAMICS

Sialon陶瓷因其具有优异的高温机械性能而成为最重要的结构陶瓷材料之一。与Si3N4相似 ,sialon陶瓷也具有α ,β两种晶体结构 ,β-sialon具有较高的断裂韧性 ,而α -sialon具有更高的硬度。文中综合介绍了α -sialon陶瓷的结构和性质 ,以及目前国内外自增韧α -sialon陶瓷的研究情况 ,具体阐述了两种制备自增韧α -sialon陶瓷的方法 :( 1)通过控制形核过程的热力学特点 ,在烧结体内原位生长柱状α -sialon晶粒以得到自增韧α -sialon陶瓷 ;( 2 )采用燃烧合成工艺 ,制备单相柱状α -sialon粉体 。

Sialon ceramics is one kind of the most important structural ceramics due to its excellent high-temperature mechanical properties. There are two well-known sialon phases, called α and β phases. It is generally accepted that α-sialon grains form elongated shapes whereas α-sialon grains can only form equiaxed shapes. Thus the toughness of α-sialon is usually lower than that of β-sialon, although the former is harder than the latter. The structure and properties of α-sialon ceramics, and the current research progress of self-reinforced α-sialon ceramics are introduced briefly in this paper. Two methods used to toughen the ceramics are detailed: (1) α-sialon grains are grown in situ and elongated during the sintering of dense polycrystalline bodies by controlling the thermodynamics of the nucleation progress; (2) the single phase α-sialon powder with elongated grains is fabricated by combustion synthesis and then added into the raw materials according to proper proportions in order to manufacture self-reinforced α sialon ceramics.