Chemical modification of porcelain tile surface to optimize flexural strength and Weibull modulus through the ion exchange process

Abstract

The goal of this research was to improve the ion exchange mechanism in porcelain tiles by modifying the tile surface chemically. Ion exchange, also known as chemical tempering, is a procedure for improving the mechanical qualities of porcelain tiles. So, solutions comprising alkaline and alkaline earth metals with a low ionic radius were sprayed on the surfaces of pressed unfired porcelain tiles (lithium, calcium, and magnesium). Subsequently, the porcelain tiles were sintered at the maximum densification temperature (1200 °C). The ion exchange process was carried out at 480 °C for 25 min in a eutectic mixture of molten salts with 73 wt% KNO3 and 27 wt% Ba(NO3)2. The results show that the flexural strength of the Li+/Mg+2 surface-enriched samples was 75 ± 4 MPa, representing an increase of 32% in relation to non-treated porcelain tiles and an increase of 17% in relation to the chemically tempered samples without prior modification. A significantly larger Weibull modulus (15–20) were found for the chemically modified tiles in comparison with the value for the unmodified porcelain tiles (7–8). These findings demonstrated that chemical modification of the porcelain surface can optimize the ion exchange process, resulting in increased breaking force and, as a result, flexural strength and Young's modulus. This approach can help reduce the thickness of ceramic tiles while maintaining mechanical properties. This would result in lower raw material usage and energy expenditure during production, as well as lower carbon emissions associated with the production of porcelain tiles.