Study of the chemical tempering process in industrial porcelain tiles aiming to enhance mechanical properties and reduce thickness

Abstract

This work studies the increase in flexural strength and breaking strength of porcelain tiles through chemical tempering. Ion exchange results in residual compressive stresses on the material surface. Technical porcelain tiles (60×60 cm) with 100%, 90%, and 77% of the standard thickness were selected. The tiles were pressed, dried, and sintered in an industrial kiln. The chemical tempering process was performed using a salt mixture consisting of 27% potassium nitrate (KNO₃ > 99%) and 73% fertilizer (K₂O ~ 43%). The chemical treatment was conducted at 480 °C for 25 min. The results demonstrated that the material’s mechanical properties met the current standard (ABNT 10545-4 2018). Even with the material reduced to 77% of the standard thickness, there was a 15% increase in rupture stress and a 16% increase in rupture strength. Weibull analysis confirmed the increment in mechanical properties after chemical tempering.

Keywords:
flexural mechanical strength; ion exchange; chemical treatment; porcelain tiles