Phase transition suppression, thermal and electrical properties of (YNb)0.2Zr0.6P2O7

ZrP2O7 is a promising material with excellent thermal and electrical properties. However, when temperature approaches to 563 K, it undergoes a structural phase transition, which will cause large thermal stresses. When Zr is substituted by Y and Nb, a new material of (YNb)0.2Zr0.6P2O7, was successfully prepared and the phase transition of material was effectively inhibited. This new material adopts a cubic structure similar to ZrP2O7, and exhibits medium thermal expansion (alpha = 7.1 x 10-6 K-1) in the measured range of 200-1073 K. The values of thermal conductivity from RT to 973 K are between 0.4474 W m-1 K-1 and 0.8526 W m-1 K-1, which can be comparable to the values of traditional thermal insulation materials. The dielectric constant and dielectric loss factor at the frequencies above 1 MHz are stable and low. The electrical conductivity of the material indicates that it is electronically insulating at RT-573 K.