Additional effects of rare earth elements on formation and properties of some transition metal pyrophosphates

Abstract

Transition metal phosphates have been used as inorganic pigments. By the addition of rare earth elements, new functional materials are expected to form. In this work, rare earth oxides (Y 2O 3, La 2O 3, CeO 2, and Nd 2O 3) were added in the formation systems of copper, manganese, and cobalt pyrophosphates prepared from ammonium dihydrogenphosphate and the transition metal carbonate. The thermal behaviors of the mixtures of ammonium dihydrogenphosphate, transition metal carbonate, and rare earth oxide were investigated with differential thermal analyses, X-ray diffraction, and Fourier transform infrared spectroscopy. Then, thermal products were estimated by particle size distribution, scanning electron micrographs, specific surface area, ultraviolet–visible reflectance spectra, fluorescence spectra, and acid and base resistance. The influence by the addition of rare earth elements was discussed on the kinds of rare earth elements, transition metals, the M/R ratios, and heating temperatures.