Effect of tin substitution on the chemical composition and thermal expansion properties of Zr2SP2O12

Abstract

Zr2-xSnxSyP2O12-δwas prepared using a hydrothermal synthesis method, and its thermal expansion properties were evaluated. The solid solubility limit of Sn was found to be approximately x = 0.6, and the substitution of Sn influenced the formation of defects at S sites. All Sn-substituted Zr2-xSnxSyP2O12-δ samples had smaller coefficients of thermal expansion(αv) than Zr2SP2O12. The lowest αv value obtained was approximately −125 ppm/K for Zr1.8Sn0.2S0.9P2O12‐δ at 373–453 K. Rietveld analysis revealed that the values of polyhedral volume, bond angle variance, and quadratic elongation in the MO6 octahedron of Zr2-xSnxSyP2O12-δ were larger than those of Zr2SP2O12. From these results, it was suggested that the increase in distortion caused by S vacancies can lead to increase in the lattice volume and control of CTEs.

Keywords

• negative thermal expansion
• x-ray powder diffraction
• phase transition
• hydrothermal