Effect of cerium oxide on colour hue of praseodymium–zircon yellow pigment

Abstract

The influence of cerium oxide on the colour hue of the praseodymium–zircon yellow pigment is presented in the present paper. A variety of pigment compositions were prepared by systematically altering the cerium to praseodymium oxide ratio. After milling of the raw materials the prepared powders were calcined at various temperatures for 2 h soaking times. Orange–yellow colour products were observed in each case. Colour and reflectance measurements were carried out using a spectrophotometer in order to optimise the pigment powders in terms of composition and calcination temperature. Structural characterisations on the optimised powder sample were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction analysis indicated that zircon was the major phase with traces of unreacted zirconia. From SEM, growth of the tetrahedral zircon crystals and the presence of small amount of unreacted zirconia were observed, which were in a good agreement with the results obtained from XRD. The average particle size of the sample after grinding for 1 h was found to be 12 μm. Finally, as a demonstration of the stability of the pigment, an orange–yellow glaze tile was manufactured when the pigment powder was applied in the commercial unleaded transparent glaze.