A new molten-salt-bath-free ion exchange technique for introducing Ag+ ions to sodium-containing silicate glasses

In an effort to fully exploit the merits of molten-salt-bath-free ion exchange technique for alkali-containing glasses, in this study, TiO ₂-based slurry is employed in Na ⁺ ↔ Ag ⁺ reaction rather than the conventional kaolinite-based slurry. It is experimentally verified that both soda-lime-silica glass and sodium-aluminosilicate glass preserve their optical transmittance, without any residues on their surface and unwanted distortions after ion exchange using the TiO ₂-based slurry. A position-selective ion exchange is demonstrated by way of coloration due to presence of Ag ⁰ particles in soda-lime-silica glass containing a small amount of Fe ²⁺ ions. Antibacterial activity by Ag species is ascertained to be effective in the case of Fe-free sodium-aluminosilicate glass subjected to ion exchange adopting the TiO ₂-based slurry. Here, diffusion coefficient of Ag ⁺ ions turns out to be tantamount to the corresponding diffusion coefficient values observed from the same category of glass ion-exchanged using a conventional molten-salt bath. The ion exchange technique proposed in this study would be more beneficial to applications where both optical clarity and morphological uniformity are more prioritized.