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

In order to achieve well-performing chemical strengthening behavior, the composition of 86.12( xSiO ₂- yAl ₂O ₃- zP ₂O ₅)- 9.95Na ₂O- 1.27ZnO- 2.66Li ₂O ( 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 65SiO ₂- yAl ₂O ₃- zP ₂O ₅ (15≤ y ≤ 30, 5 ≤ z ≤ 20) (Series Ⅰ) and xSiO ₂–20%Al ₂O ₃- zP ₂O ₅ (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 P ₂O ₅ is lower than or equal to 15 wt% roughly. The P ₂O ₅ substitution for Al ₂O ₃ accelerates the depolymerization of aluminosilicate network. Phosphorus acts as network formers in the form of P ¹ and P ² units. In the case of the P ₂O ₅ substitution for SiO ₂, the roles of phosphorus in the glass network include P ⁰, P ¹, P ² and P ³ 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 P ⁿ and the coordination number of phosphorus are the main factors effecting the ion channels.