Processing and characterisation of Pr-zircon pigment powder

Abstract

Praseodymium-zircon pigment powders were successfully prepared at different calcination temperatures with sodium fluoride NaF as mineraliser, using the solid state synthesis method. The powders were characterised using techniques such as XRD, SEM and TEM. Qualitative investigation of the phases using XRD showed the presence of large amounts of unreacted zirconia after calcination at 900 and 950°C, whereas from 1000 to 1200°C zircon was found to be the major phase, together with a small amount of zirconia. Quantitative investigation of phases was carried out using an external standard method. The weight fraction of unreacted zirconia at 1000°C was found to be 0.056. SEM observation of powders exposed at various calcination temperatures indicated the presence of tetrahedral crystals, and this was enhanced by the addition of the NaF mineraliser. TEM observations showed lattice defects and elastic strains in the samples at various calcination temperatures. © 2005 Institute of Materials, Minerals and Mining.