Thermal history and its implications: A case study for ion exchange

• Published in: Journal of the American Ceramic Society Vol. 103; no. 7; pp. 3971 - 3977
• Main Authors: Zhang, Liying, Guo, Xiaoju
• Format: Journal Article
• Language: English
• Published: Columbus Wiley Subscription Services, Inc 01.07.2020
• Subjects: Compressive properties; compressive stress; density; diffusivity; fictive temperature; Glass; Heat treatment; Ion exchange; Physical properties; refractive index; Refractivity; thermal history
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.17027

Glasses containing monovalent species can be chemically strengthened by the replacement of smaller ions in the glass with larger external ions in the near glass surface. This type of ion exchange puts glass surface under high compressive stress (CS). Glass mainly fails from tension with the presence of surface flaws. Chemical strengthening can change the stress at the flaw tip from tension to compression and further stop the flaw from propagating. Glass damage resistance is therefore significantly improved. For the same glass composition, glass thermal histories can affect the magnitude and depth of the CS generated during ion exchange. In this study, the impact of thermal history on glass physical properties and ion exchange attributes in one alkali‐containing glass formed by fusion draw process was investigated. Multiple thermal treatments were done to rewrite the glass thermal histories. Glass density, refractive index, and ion‐exchange properties as a function of the thermal treatment were studied. It is concluded that ion exchange‐related properties change dramatically with the glass thermal history.