Détermination des contraintes résidulles d'un verre traité par des méthodes thermochimiques

Abstract

The thermochemical treatment by ion exchange carried out in this study involves introducing compressive stresses on the surface of soda-lime silicate glass by immersing it in a molten potassium nitrate bath. Emphasis was placed on the effect of the treatment temperature and the immersion time on the mechanical properties such as hardness, toughness, etc. In this work, we studied the residual stresses induced around a Vickers indentation imprint, using different indentation loads on a flat soda-lime silicate glass previously treated by ion exchange at 480°C for 20 hours and at 520°C for 2 hours. Two techniques were used to determine these stresses: the first method is quantitative, Vickers indentation, while the other is qualitative, the photoelasticimetry technique. The results obtained showed that all the properties of the treated glass improved following the thermochemical treatment by ion exchange. The analysis of the residual indentation stress field using the photoelasticimetry method showed that it depends on the compressive stresses generated by the ion exchange.