碱铝硅酸盐玻璃化学强化关键影响因素概述

Overview of Principal Factors Influencing Chemical Strengthening for Alkali Aluminosilicate Glass

化学强化是一种玻璃机械强度增强方法,适用于异型、超薄、高碱、高膨胀玻璃增强,因新型超薄显示产品的屏幕保护玻璃发展需要,化学强化技术重新在碱铝硅酸盐玻璃品种掀起研究热潮。本文对化学强化本质及铝硅酸盐玻璃在屏幕保护玻璃应用进行了回顾,基于玻璃化学强化的高CS、DOL和低CT诉求,归纳总结了关键影响因素,第1,碱铝硅酸盐玻璃的成分及结构是基础,氧化铝有利玻璃网络孔隙增大创造交换通道,氧化钠或氧化锂是离子交换关键物质;第2,对于玻璃组成和结构设计,要求玻璃网络键合度R=O/Si或O/(Si+Al)满足2.15~2.40,碱金属氧化物质量分数大于13%且膨胀系数大于6×10^-6/℃;第3,在化学强化工艺方面,化学强化温度决定离子扩散系数,化学强化时间决定DOL,一步法仅能获得相对较大的CS,而DOL不很理想,只有两种离子参与交换的二步法才有利于CS和DOL同步提高。

Chemical strengthening isone of the typical methods for enhancing mechanical strength of glass,which can be especially used to strengthen special-shaped,ultra-thin,high-alkali,and high-expansion glass products.Due to the rapid development of screen protection glass for new ultra-thin touch displayer the chemical strengthening method is now very popular for alkali aluminosilicate glass products.This article reviews the nature of chemical strengthening and its application to aluminosilicate glass for screen protection glass.Based on the requirements of chemically strengthened glass,including high CS(Compressive Stress),DOL(Depth of Layer),and low CT(Center Tension),the major influencing factors are summarized.Firstly,the composition and structure of alkali aluminosilicate glass are the basis for chemical strengthening,in which alumina helps glass network pores to create exchange channels.Sodium oxide or lithium oxide is the key substance for ion exchange.Secondly,as far as the requirements of glass composition and structure are concerned,the degree of glass network bonding R=O/Si or O/(Si+Al)should meet 2.15~2.40;the alkali metal oxide content should be greater than 13%and the expansion coefficient should be greater than 6×10^-6/℃.Thirdly,in the chemical strengthening process,the chemical strengthening temperature determines the ion diffusion coefficient,and the chemical strengthening time determines the DOL.The one-step method can obtain relatively large CS only,but the DOL is not satisfactory,whereas,the two-step method in which two ions are involved in the exchange is beneficial to the simultaneous improvement of CS and DOL.