Effect of titanium substitution on the improvement of the thermal expansion properties of Zr2S0.9P2O12-δ

Abstract This paper reports on the effect of Ti substitution on the thermal expansion behavior of Zr2-xTixS0.9P2O12-δ. The solid solubility limit of Ti in Zr2-xTixS0.9P2O12-δ was approximately x = 0.7 and could be classified into two types of Zr2-xTixS0.9P2O12-δ: x = 0–0.38 and x = 0.46–0.7. The all-Ti-substituted Zr2-xTixS0.9P2O12-δ had a smaller lattice volume than Zr2S0.9P2O12-δ. Zr2-xTixS0.9P2O12-δ (x = 0–0.38) showed a similar thermal expansion behavior to Zr2S0.9P2O12-δ, but Zr2-xTixS0.9P2O12-δ (x = 0.46–0.70) was less deformable than Zr2-xTixS0.9P2O12-δ (x = 0–0.38). In other words, Ti has two effects: reduction of the lattice constant and inhibition of the phase transition. Zr1.62Ti0.38S0.9P2O12-δ had the smallest lattice volume among the chemical compositions with a dynamic phase transition and had the lowest αv value of −114 ppm/K at 393–453 K.