Self-patterning of porosities in the CaO–Al2O3–TiO2–P2O5 glass–ceramics via ion exchange and acid leaching process

Abstract

The present work aims to obtain a predetermined arrangement of porosities through acid leaching of the ion-exchanged glass–ceramics in the CaO–Al2O3–TiO2–P2O5 system. It was found that silver nanoparticles can decrease the crystallization temperature of the relevant glasses more than 100°C. Due to the nucleating role of silver particles in the crystallization process of the parent glass, it was attempted to crystallize the selected areas of the glass according to a selective arrangement. In this regard, adequate amounts of silver ions were introduced into these selected areas via ion-exchange process. In the ion exchange step, utilizing potassium ions exchanged by the silver ions from the silver nitrate melt at 300°C for 120min provided acceptable amounts of silver in the glass surface.Finally, reducing heat treatment followed by crystallization heat treatment and leaching of the low chemically resistant crystalline phases led to the formation of a desired arrangement of porosities in the glass.