普通钠钙玻璃SCC特性的测试与分析

本文探索出一种玻璃材料SCC特性的有效测试方法,并对普通钠钙玻璃在水,甲醇和甲酰胺三种介质申的SCC特性进行了测试与分析。结果表明,其da/dt-K_I曲线均无平台阶段,这是因为三种介质均是普通钠钙玻璃的活性促进剂。三种介质的SCC敏感性依次为水>甲醇>甲酰胺。进一步讨论认为,SCC敏感性与介质的未共享电子轨道的非对称性及给质子键的活性成正相关关系。

Measurement and Analysis of the SCC Characteristics for Soda-Lime-Silica Glass

White et al 2] in 1986 still used constant-moment DCB(Double Cantilever Beam) method to measure indirectly crack propagation of SLC (Soda-Lime-Silica) glass. This is perhaps because direct measurement is very difficult. The main contribution of this paper is to employ, for the first time, a different DCB method to measure directly crack propagation of SLS glass. The authors select DCB specimen with double guiding grooves and employ what the authors call IDIC (increasing load-decreasing load-increasing load-constant load)method to measure continuously the curve relating da/df(crack growth velocity) to K_I(stress intensity factor). Then it becomes possible to determine a certain load spectrum that is related to DCB precracking and DCB stable crack propagation of glass. This load spectrum is very difficult to determine but is the key to the direct measurement of crack propagation of glass. Another contribution of this paper is the preliminary experimental confirmation of the theoretical prediction made by Michalske about the sensitivity of SLS glass to methanol4]. The authors measure and analyze the SCC(stress corrosion cracking) characteristics of SLS glass immersed respectively in three different types of active environments: water, methanol, formamide. The da / dt vs K_I curves show that the sensitivity of SLS glass to methanol is less than that for water but more than that for formamide. The authors deem preliminarily that the SCC sensitivity of SLS glass to environments can be correlated to the asymmetry of lone-pair obital and the activity of proton-donor bond.