微晶玻璃的析晶及性能的影响
(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 以SiO2-Al2O3-B2O3-K2O-Li2O为玻璃组成，P2O5和ZrO2为复合成核剂，Sb2O3为澄清剂，Y2O3为添加物，通过传统熔体冷却方法制得了该系统基础玻璃。利用DSC、XRD、SEM及性能测试等手段，研究了Y2O3含量的变化对玻璃析晶行为、析出晶相种类、晶粒尺寸、晶粒分布以及微晶玻璃的力学性能的影响。研究结果表明：随着Y2O3含量的增加，玻璃的析晶峰值温度升高，且析晶峰也逐渐变宽、变钝；Y2O3的加入并不影响微晶玻璃中主晶相的组成，但对其微观结构有明显影响；当Y2O3含量低于2.0%(摩尔分数)时，微晶玻璃的抗弯强度随Y2O3含量增加而增加；当Y2O3含量为2.0%时，获得微晶玻璃的抗弯强度值最高，达到217 MPa；当2.0%≤x(Y2O3)≤2.5%时，抗弯强度反而降低；当Y2O3含量为2.5%时，获得的微晶玻璃具有良好的半透明性，并具有较好的力学性能(抗弯强度为198 MPa)；与一步法热处理相比，采用两步晶化热处理有利于提高微晶玻璃的力学性能。
关键字: 硅酸锂；微晶玻璃；析晶；力学性能；透明性
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Non-ferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The SiO2-Al2O3-B2O3-K2O-Li2O glass doped Y2O3 was prepared by traditional melting quenching method, which introduced P2O5 and ZrO2 as nucleating agent, Sb2O3 as clarifying agent and Y2O3 as additive. The effects of Y2O3 content on the crystallization behavior, crystalline phase, crystal dimensions, crystalline distribution and mechanical properties of the glass-ceramics were investigated by DSC, XRD, SEM and property measurement. The results show that, with increasing Y2O3 content, the crystallization peak temperature rises and the peak band becomes broader and blunter for this system glass. Y2O3 has obvious influence on the microstructure, however, it doesn’t change the main crystalline phase of the glass-ceramics. When the Y2O3 content is lower than 2.0% (mole fraction), the bending strength increases with the increase of Y2O3 content. The glass-ceramics containing 2.0% Y2O3 has the highest bending strength of 217 MPa. When 2.0%≤x(Y2O3)≤2.5%, the bending strength decreases with increasing Y2O3 content. When Y2O3 content is 2.5%, the glass-ceramics has higher bending strength, about 198 MPa, and excellent transparent property. Compared with one-step crystallization heat treatment, the two-step crystallization heat treatment is helpful to improve the mechanical properties of glass-ceramics.
Key words: lithium disilicate; glass-ceramics; crystallization; mechanical properties; transparency
