Development of New High Temperature Piezoelectric Materials

Conventional piezoelectric materials based on PZT have a transition temperature of around 350degC, providing reliable operation up to only 250degC. However, there is considerable need for high temperature actuation and sensing, for example the aerospace industry has a requirement for technologies that will perform in extreme environments. We report on an exciting group of high temperature piezoelectric materials with a transition temperature above 600degC. In addition to this, these materials are capable of generating a maximum strain of 0.23%, with a high field d₃₃ of 115 pm V^-1. These materials can be sintered at temperatures suitable for multilayer fabrication without the use of precious metal electrodes. SEM images reveal the materials to be fine grained, with an average particle size of the order of 0.25 - 1.0 microns, making them suitable for intricate machining and post processing.