Chemically strengthened glass for architectural applications

Abstract

Chemically strengthened glass is commonly used for applications that require high strength, such as boat and train windshields, control towers and the like. The strengthening process provides the glass with a surface residual stress that outperforms other strengthened glass types, such as thermally toughened glass. However, its use has been limited, probably for two main reasons: its high cost compared to other strengthening method and the perceived loss of the strengthening if glass surface is damaged. With the recent developments in the field of thin glass, where chemical strengthening is the only possible pre‐stressing method, there is the opportunity to better understand the process and the procedure to make it a safe material for architectural applications. In this paper, an extensive investigation on chemically strengthened glass is presented. Different parameters are considered, such as different thicknesses and chemical strengthening process conditions. The work consists of photoelastic measurement and destructive test. The data arising from the tests are elaborated with the purpose of suggesting a method to calculate the design strength of chemically strengthened glass according to the existing design standards. It is highlighted the importance to qualify chemically strengthened glass in terms of its residual stress profile.

Mechanical, thermal, and structural investigations of chemically strengthened Na2O–CaO–Al2O3–SiO2 glasses

“…Some chemical strengthening procedures involve multiple consecutive ion-exchange processes, which are beneficial for producing an engineered stress profile (ESP) with a controlled RCS profile in the surface (Green et al, 1999). Chemically strengthened (CS) glasses are nowadays widely used for flat-screen covers in handheld electronic devices (Varshneya and Bihuniak, 2018), pharmaceutical cartridges (Morandotti and Zuccato, 2018), and for impact-resistant front windows in high-speed trains, aircrafts, and high-security windows (Sheikh et al, 2020); their utilization is expected to expand to various architectural (Zaccaria et al, 2021), automotive (Jacoby, 2018), solar (Allsopp et al, 2020), and flexible photonics (Macrelli et al, 2020) purposes.…”

Experimental strength characterisation of thin chemically pre-stressed glass based on laser-induced flaws

“…This relatively thick compressive pre-stress region reduces the risk of flaw penetration to the tensile region (Schwind et al 2020;Zaccaria and Overend 2020). However, the magnitude of the pre-compressive stress is significantly lower than that of chemically pre-stressed glass (Zaccaria et al 2021). There are different terminologies in the literature to describe chemically prestressed glass, such as strengthened glass, toughened glass, and tempered glass.…”

The clamp bender: a new testing equipment for thin glass

“…The point where the compression changes to tension is known as depth of layer (DoL) or case depth. The surface compression and the case depth are the main parameters that drive the strength of chemically strengthened glass: the target is that the DoL would be larger than any pre-existing or usage-induced flaw (Zaccaria et al 2021). In contrast, any flaw deeper than the DoL will severely affect its strength as its tip will be under the core tension (Datsiou et al 2017).…”