Microstructure and mechanical properties of diopside and anorthite glazes with high abrasion resistance

Abstract The paper presents the results of research on the influence of the chemical composition of frits on the microstructure and mechanical properties of ceramic glazes. Glaze sets are designed based on frits of different chemical composition and increasing B2O3 content. Thermal DSC analysis showed a high tendency to crystallize the designed glazes, and in the obtained glazes the main crystalline phases were diopside or anorthite, which was also confirmed by XRD analysis and SEM microscopic observations. In glazes not containing B2O3 and at a SiO2/Al2O3 molar ratio in the 5.3–5.6 range, mainly diopside crystallized, while a decrease in the SiO2/Al2O3 molar ratio to a value below 4.9 and an increase in B2O3 content contributed to an increase in the anorthite crystal phase content. The obtained glazes were characterized by a surface roughness of Ra in the range of 0.2–1.1 μm and a high abrasion resistance measured with a mass loss of less than 50 mg after 6000 abrasion cycles in accordance with the EN ISO 10545-7 standard. Such high abrasion resistance was achieved thanks to the high hardness of the glazes in the range of 6.4–8.0 GPa, which was confirmed by the Vickers hardness measurement.