Investigation of the effects of raw materials containing calcium oxide on the body of glaze

Glazes that provide aesthetic diversity on ceramic surfaces are not only visual elements but also functional components that determine the technical characteristics of the surface. Throughout history, ceramic glazes have been used for both functional and aesthetic purposes; research focusing on material knowledge and surface effects has offered new means of expression for artists. The raw materials used in glaze formulations play a decisive role in the formation of features such as color, gloss, mattness, transparency, and texture. In this study, four different raw materials containing calcium oxide (CaO) calcite, marble, dolomite, and wollastonite were comparatively examined in terms of their effects within the glaze structure, where CaO acts as a flux. The research was conducted using an experimental methodology, and systematic glaze recipes were developed and tested within standard, binary and ternary glaze systems. Firings were carried out at 1160°C using Fine Fire Clay (FFC) casting body, and the glazes were applied by spraying and pouring techniques. Initially, a standard transparent base glaze was used, to which the CaO sources were added in specific ratios; subsequently, combinations of these materials were evaluated. The resulting glaze surfaces exhibited diverse textural qualities, including matte, semi-matte, crackled, transparent, silky matte, and rough effects. The successful glaze recipes were enriched with coloring oxides and re-applied in personal artistic explorations. This thesis aims to contribute to the enrichment of aesthetic diversity in ceramic art by examining the effects of different CaO sources on glaze surface characteristics.