Formation and Color of the Spinel Solid Solution in CoO-MgO-Cr<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub>-SnO<sub>2</sub> System

Abstract

This study was concerned with the formation, color development and application for colored glazes of the spinel solid solution in CoO-MgO-Cr2O3-TiO2-SnO2 system.Specimens were prepared by calcining the oxide mixtures at 1400°C for 1hr. Concerning each specimens, the formation of spinel solid solution was investigated by X-ray diffraction, the color was discussed by means of spectral reflectance and the stability for various glazes was tested. The results were summarized as follows.1. A formation of continuous solid solution and an obedience to Vegard's law were confirmed by X-ray analysis.2. In MgO-Cr2O3-TiO2-SnO2 system, as the amount of Cr3+ increased, color ranged from yellow green through leaf to grayish leaf, and the absorption of Cr3+ shifted towards violet region.3. Colors which developed in CoO-MgO-Cr2O3-SnO2 system ranged from blue to bluish green, and the absorption of Cr3+ shifted towards violet region with increasing amount of Cr3+.4. As the amount of Cr3+ increased, colors obtained in CoO-MgO-Cr2O3-TiO2 system, ranged from bluish green through green to bluish green, and the absorption of Co2+ and Cr3+ shifted towards violet region.5. CoO-MgO-TiO2-SnO2 system revealed the colors ranging from blue to bluish green, and the absorption of Co2+ shifted towards red region as the amount of Ti4+ increased.6. Colors ranging from bluish green to green developed in CoO-MgO-Cr2O3-TiO2-SnO2 system.7. According to the results of the colored glaze tests, the specimens with the composition in Cr3+ rich region were appreciated to be stable as a glaze stain.