ZrO2 (Zirconium Dioxide)

Notas

Zirconium dioxide, or zirconia, is a white crystalline oxide occurring naturally in a monoclinic form known as baddeleyite. In ceramic applications, it is recognized for its exceptional refractory nature, exhibiting a melting point reaching approximately 2700°C. Within a glaze matrix, it acts primarily as an opacifying agent, typically introduced via zirconium silicate. Because it resists dissolution into the melt, it remains suspended, providing opacity. However, incorporating small quantities (up to 3%) into transparent glazes can enhance surface hardness and chemical durability, as these minor amounts may fully integrate into the glassy phase. Zirconia significantly influences glaze rheology by increasing surface tension and decreasing melt fluidity due to its high heat resistance. Regarding thermal expansion, it tends to lower the overall coefficient of a glaze; however, because its mechanism differs from oxides that fully incorporate into the melt, its impact on thermal contraction can be unpredictable compared to standard calculated values. Additionally, zirconia is utilized in the production of ceramic stains to provide color stability and to encapsulate volatile elements, preventing them from escaping during the firing process.