Correlation between K+-Na+ diffusion coefficient and flexural strength of chemically tempered aluminosilicate glass

The correlation between K+-Na+ diffusion coefficient and mechanical properties of chemically tempered and hybridly tempered (thermally plus chemically tempered) aluminosilicate glass is investigated. First, the profile of the potassium ion concentration is experimentally measured, and the diffusion coefficient is calculated according to the Boltzmann-Matano approach. Second, the flexural strength and the Weibull modulus are determined using a method combining experimental (coaxial double ring) and finite element analysis. The results indicate that the flexural strength decreases with the diffusion coefficient of the air side for both types of glass samples, while there is no significant relationship between the diffusion coefficient and the Weibull modulus. The diffusion coefficient on the air side shows a higher value than that on the tin side. With the same diffusion coefficient, the flexural strength of chemically tempered glasses is found to be higher than that of hybridly tempered glasses. The effect of the diffusion coefficient on the modulus of rupture (MOR) for the hybridly tempered glass is more remarkable. These results would be useful for designing the glass strength and guiding the strengthening process by chemical or hybrid tempering.