Suppressing the phase transition of ZrP2O7 by defect and entropy regulation for high-temperature wave-transparent material application

Abstract

ZrP2O7 is a promising wave-transparent material due to its low dielectric constant and low dielectric loss, but its inherent phase transition characteristic at approximately 300 °C limits its high-temperature application. Therefore, suppressing the phase transition is necessary for ZrP2O7 to serve in extremely harsh environments. In this work, introducing Ti and Hf into ZrP2O7 causes significant lattice distortion and an increase in entropy, both of which synergistically limit the crystal structure transformation. In addition, enhanced phonon scattering by mismatch of atomic mass and local distortion leads to a reduction in the thermal conductivity. Lattice distortions also cause changes in both bond length and tilting angle, so that (Ti1/3Zr1/3Hf1/3)P2O7 does not undergo sudden expansion as does ZrP2O7. (Ti1/3Zr1/3Hf1/3)P2O7 maintains excellent dielectric properties, which highlights it as a promising high-temperature wave-transparent material.

Keywords

• wave-transparent material
• medium-entropy ceramics
• phase transition
• dielectric constant
• thermal expansion
• thermal conductivity