Formation and transformation of cubic lead niobate pyrochlore solid solutions

Abstract

Formation of lead niobate pyrochlores by the reaction of PbO with Nb2O5 in various molar ratios and at various temperatures has been investigated. It has been shown that for a PbO/Nb2O5 molar ratio between 1.5 and 3.0, a pyrochlore solid solution having cubic symmetry is formed at low temperatures (approximately 500-600 °C). X-ray diffraction data show evidence for the existence of compositional inhomogeneity for this phase which contains part of the Pb in the Nb site leading to the formula Pb1.5+x(Nb2-yPby)O7-δ (0.0