Effects of alkali metal oxides on crystallization behavior and acid corrosion resistance of cordierite-based glass-ceramics

MgO-Al2O3-SiO2-TiO2 glass-ceramics with 3 mol% alkali metal oxides were prepared, and the 3 mol% alkali metal oxides were induced by 3 mol% Na2O only, 1.5 mol% Na2O + 1.5 mol% Li2O, and 1.5 mol% Na2O + 1.5 mol% K2O, respectively. Effects of alkali metal oxides on the crystallization behavior and acid corrosion resistance of the MgO-Al2O3-SiO2-TiO2 glass-ceramics were investigated. The results showed that μ-cordierite precipitated in the glass matrix firstly, and it changed into α-cordierite with the crystallization temperature increasing. Using K2O substitution of Na2O hindered the precipitation of cordierite, while the addition of Li2O promoted the precipitation of μ-cordierite at low temperatures. When the main crystalline phase was μ-cordierite, the acid resistance of the glass-ceramics was significantly improved compared with the base glass. With the main crystalline phase changing from μ-cordierite to α-cordierite, the acid resistance of the glass-ceramics became worse, which was related to the honeycomb structure of α-cordierite. When 1.5 mol% Na2O was replaced by Li2O, the glass samples crystallized at 880 °C showed the optimum acid resistance with the minimum weight loss ~ 0.096%.