Preparation of copper-red glazes by in-situ reductive process and its coloring research

A unique preparation method for copper-red glaze is investigated by using nano-SiC to reduce CuO nano-materials in an oxidizing environment. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and fourier-transform infrared spectroscopy were used to investigate the influence of nano-SiC content on the crystalline phase evolution and phase separation of the copper-red glaze. The results indicate that the added nano-SiC can promote the crystallization of SiO2 and increase the average diameter of phase separation in the glaze. The color of the samples containing 0.01 to 0.3 mass% SiC become redder in hue after calcination in an oxidizing atmosphere. Interestingly, the structural color forms due to Rayleigh scattering, which may account for the slightly blue hue of glaze-fired samples containing different amounts of nano-SiC. The viscosity of the molten glazes decreases with increasing nano-SiC content. A possible in-situ reductive mechanism is proposed to explain how the red color is generated and changes with the amount of nanosized SiC. (C)2017 The Ceramic Society of Japan. All rights reserved.