A lead-free non-ferroelectric piezoelectric glass-ceramic for high temperature surface acoustic wave devices

Abstract A piezoelectric glass-ceramic containing Sr2TiSi2O8 crystals is synthesized and used to develop a SAW device tested up to 950 °C. This device consists of an input IDT that generates the wave and an output IDT that converts it into a measurable electrical signal. The evolution of amplitude and frequency of the output signal is recorded. This study highlights that the glass-ceramic remains able to generate and propagate SAW up to 950 °C. The variations of the signal between room temperature and 950 °C are discussed with respect to the thermomechanical properties of the glass-ceramics. The softening of the residual glass above its Tg increases the signal’s amplitude thanks to the relaxation of the stresses. At higher temperatures, the low residual glass viscosity causes the damping of the SAW. Below Tg, the variations of the signal are explained by the thermal expansion mismatch between the crystals and the glass, inducing tensile stresses and damages.