Novel glass-ceramic glazes with enhanced surface properties for porcelain stoneware tiles

Porcelain stoneware tiles are globally recognised as a high-quality material, characterised by exceptional physio-mechanical and technological properties, as well as high aesthetic appeal. Owing to these valuable characteristics and their versatility, porcelain stoneware tiles have become one of the most widely adopted materials in the building and construction industry. To preserve their aesthetic appeal and protect them from wear during their service life, these tiles are typically coated with a thin layer of glass-ceramic glaze. Despite their advantageous properties, the intended uses of ceramic tiles are usually evaluated using the test methods specified in the ISO EN 10545 standards. However, these standards may be unsuitable for fully assessing their surface performance. In this study, a glass-ceramic glaze for porcelain stoneware tiles with enhanced surface properties and an anti-reflective (matt) finish was developed and produced at the industrial pilot plant level. Specifically, this glaze was developed through research on multiple formulations, exploiting a characterisation protocol that synergistically combines analytical and technological tests to define key parameters for optimising wear resistance. This protocol was specifically designed in this thesis to address the limitations of standard methods commonly used by ceramic manufacturers to evaluate ceramic tile surface performance. Finally, to enhance the slip resistance of the glaze, a specific study was carried out by adding micro-grits with varying levels of fusibility and grain sizes to glaze formulations. The use of micro-grits with an average size of 70 μm, which do not fully melt during the firing process, facilitated the development of functionalised surfaces with high slip resistance, thereby reducing the risk of slips, falls, and associated injuries.