LAUSR

In order to identify suitable substrate materials for sue in high-temperature pressure sensors that can operate above 1000°C, the high-temperature properties of four high-performance ceramics (99% pure Al2O3 (99Al2O3), 97% pure Al2O3 (97Al2O3), sapphire, and ZrO2) were investigated. Three-point bend testing was used to measure the flexural strengths and flexural moduli of these ceramics, and transient laser emission was used to measure their thermal conductivities. The samples were prepared by hot-press sintering: plates with the dimensions of 3.5 × 5 × 50 mm3 for the bend testing and rods of φ12.5 × 1.5 mm3 for the thermal conductivity measurements. Curves showing the dependence of flexural strength, flexural modulus, and thermal conductivity on temperature were obtained. The results show that the flexural strength and thermal conductivity of sapphire are much greater than those of the other ceramics tested. Thus, we conclude that sapphire is the most appropriate of these materials for use in high-temperature pressure sensors for operation at up to 1000°C.