Structural investigations of CaO-CaF2-SiO2-Si3N4 based glasses by Raman spectroscopy and XPS considering its application to continuous casting of steels

Abstract

Structural analysis of CaO-CaF2-SiO2-Si3N4 based glass was conducted in order to understand its viscoelastic properties. CaO-CaF2-SiO2-Si3N4 based glass has been adapted in various industries because a small amount of nitrogen incorporation leads to enhancing many properties such as fracture toughness, viscosity and chemical durability. Recently, few metallurgists have begun to use CaO-CaF2-SiO2-Si3N4 based glass as a lubricant of continuous casting process of steel in order to maximize its viscoelastic property by controlling degree of polymerization (DP). The present study provides structural understanding of CaO-CaF2-SiO2-Si3N4 based glass, specifically designed for the continuous casting process of steel by Raman spectroscopy and XPS. With Raman spectroscopy, the degree of polymerization (DP) was evaluated by the Q(3)/Q(2) ratio. The qualitative analysis of nitrogen and non-bridging oxygen was conducted by XPS within a range between 0.1 and 6 wt.% of nitrogen. According to the results, the introduced nitrogen was incorporated with non-bridging oxygen of silicate network units, resulting in increase on degree polymerization (DP) of silicate network units. Such structural changes would potentially enhance shear thinning property of CaO-CaF2-SiO2-Si3N4 based glass, resulting in a positive influence on continuous casting process of steel. (C) 2015 Elsevier Ltd. All rights reserved.