微晶玻璃的析晶及性能的影響
(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 中南大學 有色金屬材料科學與工程教育部重點實驗室，長沙 410083)
摘 要: 以SiO2-Al2O3-B2O3-K2O-Li2O為玻璃組成，P2O5和ZrO2為復合成核劑，Sb2O3為澄清劑，Y2O3為添加物，通過傳統(tǒng)熔體冷卻方法制得了該系統(tǒng)基礎玻璃。利用DSC、XRD、SEM及性能測試等手段，研究了Y2O3含量的變化對玻璃析晶行為、析出晶相種類、晶粒尺寸、晶粒分布以及微晶玻璃的力學性能的影響。研究結果表明：隨著Y2O3含量的增加，玻璃的析晶峰值溫度升高，且析晶峰也逐漸變寬、變鈍；Y2O3的加入并不影響微晶玻璃中主晶相的組成，但對其微觀結構有明顯影響；當Y2O3含量低于2.0%(摩爾分數)時，微晶玻璃的抗彎強度隨Y2O3含量增加而增加；當Y2O3含量為2.0%時，獲得微晶玻璃的抗彎強度值最高，達到217 MPa；當2.0%≤x(Y2O3)≤2.5%時，抗彎強度反而降低；當Y2O3含量為2.5%時，獲得的微晶玻璃具有良好的半透明性，并具有較好的力學性能(抗彎強度為198 MPa)；與一步法熱處理相比，采用兩步晶化熱處理有利于提高微晶玻璃的力學性能。
關鍵字: 硅酸鋰；微晶玻璃；析晶；力學性能；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
