Growth and Characterization of Ca₂Al₂SiO₇ Piezoelectric Single Crystals for High-Temperature Sensor Applications

Abstract

The electrical properties of a piezoelectric single crystal of calcium aluminate silicate Ca2Al2SiO7 (CAS) were studied at elevated temperatures and its applicability to high-temperature pressure sensors was investigated. The CAS bulk single crystal was grown by the Czochralski method. The piezoelectric d 14 and d 36 constants were respectively evaluated as 6.04 and 4.04 pC/N by the resonance and antiresonance method. The temperature dependence of the piezoelectric constant was investigated at temperatures up to 500 °C. The electrical resistivity at 800 °C was on the order of 108 Ω·cm along both the crystallographic a- and c-axes. The measurement of direct piezoelectric response at 700 °C demonstrated that the CAS crystal could detect a pseudo-combustion pressure change of an automobile engine. Our observations suggest that CAS crystals are superior candidates for sensing pressure at high temperatures.

Growth and characterization of strontium-substituted Ca₂Al₂SiO₇ piezoelectric single crystals

“…Recently, gehlenite Ca 2 Al 2 SiO 7 (CAS) and related crystals of the melilite group have been studied. 10), 11) They exhibit stable resistivity at high temperatures, good piezoelectric properties, and easy bulk crystal growth. 10)14) Therefore, melilite crystals are expected to be promising candidates for piezoelectric materials.…”

Rare-Earth Calcium Oxyborate Piezoelectric Crystals ReCa4O(BO3)3: Growth and Piezoelectric Characterizations

“…and fresnoite crystals (point group 4mm, such as Ba 2 TiSi 2 O 8 ) were investigated for piezoelectric applications. These crystals show the merits of high melting points (1400-1700 °C) and high effective piezoelectric coefficients d eff (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) pC/N) [20][21][22][23][24][25][26]; the evaluations of the temperature dependence of dielectric, piezoelectric and electromechanical properties, however, are limited. Of particular significance is that the monoclinic rare-earth calcium oxyborate crystals (ReCa 4 O(BO 3 ) 3 , ReCOB, Re: rare earth), which have been extensively investigated for nonlinear optical applications in the last two decades [27][28][29][30][31][32][33], were reported to exhibit good piezoelectric properties and high electrical resistivity at an elevated temperature of 1000 °C, with no phase transition prior to their melting points (~1400-1520 °C) [1][2][3][34][35][36][37][38].…”

HyPix-3000 - a large area single-photon counting detector with two discriminator thresholds

“…Gehlenite (Ca 2 Al 2 SiO 7 ) is a mineral and can be made into a piezoelectric sensor working at high temperature [6]. It can be synthesized from commonly available materials.…”