Solid-state field-assisted ion exchange of Ag in lithium aluminum silicate glass-ceramics: A superfast processing route toward stronger materials with antimicrobial properties

Lithium-aluminum-silicate glass-ceramics (LAS) are of pivotal relevance in various applications as they combine excellent mechanical and functional properties. Due to their use in medical devices and cooking articles, antimicrobial properties are obviously of interest. Herein, we report the solid-state field-assisted (Ag→Li,Na) ion exchange in LAS glass-ceramics containing β-quartz and β-spodumene solid solutions. The ion-exchange is extremely rapid and deep silver penetration (>100 μm) can be achieved within a few minutes (<5 min), this being proportional to the treating time and applied current. The elemental profiles are characterized by a relatively complex shape which reflects the different alkali mobility in the different phases. The ion exchange initiates structural modifications involving: (i) β→α transition in spodumene; (ii) formation of lattice microstrain and quartz cell expansion; (iii) substantial changes in the IR absorption spectra. The obtained materials possess improved resistance to crack formation and antimicrobial activity against Staphylococcus aureus.