Work

Measurement of stress build‐up of ion exchange strengthened lithium aluminosilicate glass

Year: 2019

Type: article

Abstract: A recently developed nondestructive method was used to investigate the stress build‐up in chemically strengthened lithium aluminosilicate glass. We utilized an updated version of the gradient scattered light method, which now enables more precise determination of the depth coordinates, recovering a more detailed stress profile around the knee. The main motivation of the work was to characterize and optimize the development of the knee‐shaped breaking point in stress profile in lithium aluminosilicate glass prepared by the Saunders‐Kubichan method of one‐step strengthening in a mixture of KNO 3 +NaNO 3 molten salt bath. In the industry, a two‐step process is still commonly used to build such a stress profile; the one‐step strengthening will simplify the process as well as save the cost. Compared to previous studies, which used a destructive method based on transmitted light photoelasticity, we found that in the samples ion exchanged for 24 hours, the knee‐shaped breaking points were situated two times deeper whereas the case depths were 28% shallower. The measured stress profiles were validated by stress equilibrium and by comparison to Na + ion concentration profiles.

Source: Journal of the American Ceramic Society

DOI: 10.1111/jace.16913