Effects of cobalt, copper, manganese and titanium oxide additions on the microstructures of zinc containing soft porcelain glazes

Different types of glazes, which are nearly all based upon silicate compositions, are used to meet a wide range of requirements in service. Many artistic effects are achieved by departing from a clear, smooth, transparent system. Coloured glazes are produced by several means such as the inclusion of colouring oxides, addition of stains, dispersing finely divided particles and the use of precious metals, applied in the form of lines or bands, or even screen-printed patterns. Colouring oxides commonly used include iron, copper, cobalt, chromium, manganese, nickel, vanadium, cadmium and selenium. Zinc oxide has a beneficial effect in many coloured glazes amongst which crystalline ones are more noteworthy. With this paper the effects of CoO, CuO, MnO2 and TiO2 additions into zinc oxide containing crystal glazes differentially heat-treated are described on micro-scale appearances. Experimental techniques used were X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX).