Chemical ageing and microstructural changes of glazed ceramic tile surfaces

The aim of the work is to investigate the chemical durability of glazed tile surfaces under basic solution, in terms of microstructural changes. Several glazed ceramic tiles, characterised by different microstructures, were considered. The working surfaces were subjected to chemical attack by using a strong basic agent, and the chemical analysis of the leached solutions were carried out. The glazed surfaces of the samples, before and after the chemical attack, were analysed from a microstructural point of view. Scanning electron microscopy, roughness measurements and X-ray diffraction analysis allowed to detect the main microstructural changes. The results gave indications on the elements released by chemical attack, allowing to deepen the role played by the glassy and crystalline phases in the leaching mechanisms.