摘要
以SiO2-Li2O-K2O-B2O3-P2O5为基础组成,P2O5为形核剂,采用传统熔体冷却法制备了该系统基础玻璃。利用DSC、XRD、SEM等检测手段研究了热处理制度对玻璃析晶行为、析出晶相种类、晶粒尺寸、晶粒分布及微晶玻璃力学性能的影响。结果表明,当引入P2O5为形核剂时,玻璃在核化温度范围内发生分相,并诱导Li2SiO3的异相成核。随温度的升高,亚稳态的Li2SiO3最终转变成Li2Si2O5稳定相。基础玻璃经核化处理后,分两步晶化比一步晶化更有利于Li2Si2O5的生长,并在一定程度上提高了微晶玻璃的抗弯强度。延长晶化时间能使Li2Si2O5晶体进一步生长,联锁微观结构聚集体的尺寸增大,晶粒与晶粒间交联程度更高,晶粒间有更牢固的化学键合,抗弯强度有所提高。
The SiO2-Li2O-K2O-B2O3-P2O5 glasses introducing P2 O5 as the nucleating agent are prepared by traditional melting quenching method. The effects of heat treatment conditions on the crystallization behavior, crystalline phase, crystalline distribution, crystal dimensions and the mechanical properties of the glass-ceramics are investigated by DSC, XRD and SEM. The results show that PzOs is an efficient nucleating agent and can induce phase separation to promote heterogeneous nucleation of Liz SiO3 in SiO2-Li2O-K2O-B2O3-P2O5 glass system. With the increasing of the crystallization temperature, the unstable Li2 SiO3 crystal phase disappears and is transformed into stable LizSizOs. Compared with one-step crystallization treatment, after the precursor glasses are treated at the nucleating tempera- ture, two-step crystallization treatment is more favorable for growing up of Li2Si2O5 and enhancing of bending strength of the glass-ceramics. And the crystal phase doesnPt change by prolonging the crystallization time, however, it can make the Liz Si2O5 crystal further grow, the interconnection microstructure aggregate size increase and the ben- ding strength of the glass-ceramics enhance because of stronger bonding among the crystal grains.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2009年第22期65-69,共5页
Materials Reports
基金
国防军工新材料项目(JPPT-115-329)
关键词
二硅酸锂
微晶玻璃
热处理
抗弯强度
显微结构
lithium disilicate, glass-ceramics, heat treatments, bending strength, microstructure
