Effect of Cobalt Oxide and Copper Oxide Additions to Zinc-Containing Soft Porcelain Glazes

摘要

Chromium, cobalt, iron, uranium, copper, gold, vanadium and zirconium oxides are the most prominently used ceramic coloring agents. To be suitable as a ceramic color, a material must have strength of pigmentation and stability. The color of an atom depends on its environment. This is particularly true of chromium. Chromium compounds normally are green, but in combination with tin and Al_2O_3, pinks and red are produced. The influence of environment is far less pronounced with cobalt, which, similar to most other coloring elements, undergoes changes in shade. However, cobalt does not give completely different colors, as does chromium, if exposed to various environments. Crystalline glazes containing up to 10% CoO remain blue. Bodies and engobes can carry more cobalt than glaze without becoming black.