We report the effect of Sr substitution on the structural, electrical, and mechanical properties of Ca2Al2SiO7 (CAS) piezoelectric single crystals for high-temperature pressure sensors. Single crystals of Sr-substituted CAS (Sr-CAS) with a nominal chemical composition of CaSrAl2SiO7 were grown by using the Czochralski technique. The single-crystal X-ray structure analysis revealed that Sr atoms were placed in the Ca decahedral sites, which decreased the polyhedral distortion slightly. The piezoelectric modulus d′31 and electrical resistivity of Sr-CAS measured at 23°C were slightly lower than those of CAS, but still sufficient for the satisfactory performance of the produced sensors. The rupture strength of the Sr-CAS crystal was 230 MPa, 1.2 times higher than that of a CAS crystal. The obtained results suggest that Sr-CAS crystals can be candidate materials for high-temperature pressure sensors.
2017 The Ceramic Society of Japan