Ceramic glazes are glassy coatings applied to ceramic product surfaces. Glaze compositions were formulated using the Unity Molecular Formula (UMF), and changes in the surface and mechanical properties, crystalline phases, ion leaching characteristics, and molecular structures were investigated. The results indicated that the properties of the glaze were influenced by SiO₂ and Al₂O₃ additions as well as their respective ratios. An increase in the SiO₂ content reduced glossiness, whereas an increase in the Al₂O₃ content enhanced glossiness. Crystalline phases were observed on the glaze surface of the samples with the highest SiO₂/Al₂O₃ ratio of 10.5. Both α-quartz and α-cristobalite phases were formed in the heat-treated glazed surfaces, where an increase in the SiO₂ content increased the cristobalite crystalline phase fraction. Raman spectral analyses of the glaze indicated that an increase in the SiO₂/Al₂O₃ ratio correlated with an increased Q₀ ratio. Additionally, the SiO₂/Al₂O₃ ratio affected the hardness and ion leaching characteristics of the glaze, exhibiting contrasting trends with a transition point at approximately 8.5. The findings of this study can potentially serve as guidelines for predicting changes in the glaze properties resulting from compositional variations in the Stull diagrams.

Keywords: Glaze, Unity molecular formula, Properties, Crystalline phases, Molecular structure.