The role of phosphate in the glass forming region, structure and mechanical properties for the SiO2-Al2O3-P2O5 system contains high-aluminum

Abstract

In order to achieve well-performing chemical strengthening behavior, the composition of 86.12(xSiO2-yAl2O3-zP2O5)- 9.95Na2O- 1.27ZnO- 2.66Li2O (x = 55–85wt%, y = 10–40wt% and z = 5–35wt%) were prepared by conventional melt-quenching technique. The glass forming region was obtained. Two compositional series of 65SiO2-yAl2O3-zP2O5 (15≤y ≤ 30, 5 ≤ z ≤ 20) (Series Ⅰ) and xSiO2–20%Al2O3-zP2O5 (60≤x ≤ 75, 5 ≤ z ≤ 20) (Series Ⅱ) have been investigated. The relationship between glass structure and composition was investigated. The results show that the transparent and homogeneous glass is formed when the glass former P2O5 is lower than or equal to 15 wt% roughly. The P2O5 substitution for Al2O3 accelerates the depolymerization of aluminosilicate network. Phosphorus acts as network formers in the form of P1 and P2 units. In the case of the P2O5 substitution for SiO2, the roles of phosphorus in the glass network include P0, P1, P2 and P3 units. Furthermore, the Series Ⅰ and Series Ⅱ glass samples were chemical strengthened. The ion-exchange depth and the elastic modulus before and after chemical strengthening were studied. The results reveal that the ion exchange depth and elasticity modulus after chemical strengthening is maximum at 64 μm and 80.5 GPa for x/z = 5.4 sample, respectively. The addition of phosphorus accelerates ion exchange, which is mainly attributed to the formation of ion channels. The number of Pn and the coordination number of phosphorus are the main factors effecting the ion channels.