Effect of ZnO/MgO ratio on the crystallization and optical properties of spinel opaque glazes

Abstract

Abstract The effect of the ZnO/MgO ratio on the crystallization and optical properties of glass‐ceramic glazes from the SiO 2 –Al 2 O 3 –ZnO–MgO–CaO–K 2 O–Na 2 O–B 2 O 3 system was studied. The glazes with different ZnO/MgO ratios were characterized by differential scanning calorimetry, X‐ray powder diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive spectroscopy analysis and a spectrophotometer. The results reveal that the A glaze without ZnO content contains forsterite and sapphirine. The B and C glazes with intermediate ZnO/MgO ratio contain enstatite and spinel solid solution. The D to F glazes with higher ZnO/MgO ratio crystallize spinel solid solution as the only crystalline phase. The amount of spinel solid solution, lightness values ( L *), gloss values and the reflectance of the studied glazes increase with the ZnO/MgO ratio.