An X-Ray Study on PbO-Nb2O5-TiO2 System

Abstract

Ternary system PbO-Nb₂O₅-TiO₂ was studied. Ceramic samples were prepared at 900°C and 1200°C in air, and analyzed by X-ray powder diffraction method. The phase diagrams for this system at the two sintering temperatures are constructed. The diagrams indicate that ternary compounds PbO-Nb₂O₅-TiO₂ (PbNb₂TiO₈) and PbO-2Nb₂O₅-3TiO₂ (PbNb₄Ti₃O₁₇) exist, and that a pyrochlore type cubic compound phase extends from 3PbO-2Nb₂O₅ site toward TiO₂-rich part of the system, covering a considerably wide region. Another single phase region near the TiO₂ region has remained unidentified. The PbNb₂TiO₈ compound is found to be piezoelectric.