Investigation of Additives and Atmospheric Effects on Reduced Copper Glaze

In this study, the influence of different parameters such as atmospheric conditions, uncontrolled (wood burning) and controlled reduction (firing in H2, CO) atmospheres as well as the amount of additives (ZnO-CoO) on reduced copper glazes have been investigated. Morphology, microstructure and composition of glaze surfaces have been studied by SEM. Color properties of different parts of glaze surfaces were investigated by Spectrophotometer. Results showed that surface color changed by different amounts of copper-cobalt-zinc oxide additives, which can be related to the formation of different metallic compounds such as brass alloy, copper, zinc as well as non-stoichiometric copper oxide and zinc oxide. SEM-EDS results indicated that brass alloy rods formed on the surface of copper glazes containing 14% zinc oxide and zinc oxide. rainbow appearance of copper glazes containing zinc oxide, specially Yellow color in the presence of 14% zinc oxide was in good agreement with SEM-EDS results. surface of this glaze and cobalt surface was compatible to While deep reduction occurred on the glaze surface during uncontrolled reduction, uniform metallic layer was detected on the glazed surfaces by controlled reduction atmosphere. This layer was formed due to continuous and long-term reducing atmosphere in the kiln. J. Color Sci. Tech. 3(2009), 199-207 © Institute for Color Science and Technology.