Compositional Effects on Indentation Mechanical Properties of Chemically Strengthened TiO₂-Doped Soda Lime Silicate...

TiO₂ is an important oxide for property modifications in the conventional soda lime silicate glass family. It offers interesting optical and mechanical properties, for instance, by substituting heavy metals such as lead in consumer glasses. The compositional effects on the hardness, reduced elastic modulus and crack resistance as determined by indentation of chemically strengthened (CS) TiO₂-doped soda lime silicate glass was studied in the current paper. The CS, which was performed by a K⁺ for Na⁺ ion exchange in a molten KNO₃ salt bath at 450 °C for 15 h, yielded significant changes in the indentation mechanical properties. The hardness of the glass samples increased, and this was notably dependent on the SiO₂, CaO and TiO₂ content. The reduced elastic modulus was less affected by the CS but showed decrease for most samples. The crack resistance, an important property in many applications where glasses are subjected to contact damage, showed very different behaviors among the series. Only one of the series did significantly improve the crack resistance where low CaO content, high TiO₂ content, high molar volume and increased elastic deformation favored an increased crack resistance.