Influence of chemical treatment on microstructure and mechanical properties of chemically-toughened glass by ion exchange process

In this study, an attempt was made to investigate the influence of immersion temperature and time of ion-exchange on the microstructure and mechanical properties of chemically toughened soda-lime glass (CTG). Glass samples of 120 × 50 × 40 mm were immersed in potassium nitrate (KNO3) salt placed inside a salt bath and subjected to heating at temperatures of 450 °C and 500 °C with the immersion time varied for 4 h and 5 h for each temperature inside a muffle furnace. Scanning Electron Microscopy (SEM) was used to evaluate the microstructure of the chemically toughened glasses while tests such as hardness, flexural strength and impact strength were used to assess the mechanical properties of the chemically toughened glasses. The results obtained show that hardness value decreased as temperature and time increases with maximum hardness of 26.35 BHN for CTG1 (450 °C for 4 h). The impact strength increased as temperature and time increases with maximum impact strength of 36.72 J for CTG4 (500°C for 5 h). However, the maximum flexural strength of 95.87 MPa was obtained for CTG2 (450 °C for 5 h).