Hiroyuki Hase

Effect of Y and Mn Doping in Pb(T, Zr)O3 Piezoelectric Ceramics on the Resonant Frequency and Capacitance Changes and Aging by Thermal Shock Tests

The effects of Y and Mn-doping in Pb(Zr, Ti)O3 (PZT) with respect to the resonant frequency changes and the aging phenomena caused by thermal treatment were studied in order to achieve a stable piezoelectric ceramic filter. Good thermal stability as well as a high mechanical quality factor QM were required for the piezoelectric ceramics to fabricate certain types of narrow band monolithic filters. The Cr-doped PZT showed a little aging phenomena in resonant frequency change after thermal shock tests, but QM was not high. The Cr and Mn-doped PZT had a large QM value, but a large amount of resonant frequency change and aging after thermal shock tests. It was observed that the PZT with the addition of Y and Mn has high QM and good temperature stability. These features were suitable for the use in filters and resonators.

Torque sensor using amorphous magnetostrictive ribbons

Abstract A torque sensor using amorphous magnetostrictive ribbons was developed. An inaccuracy of less than 1% in the temperature range − 10 to 50 °C was achieved by controlling the bias compressive stress of glued amorphous ribbons, which is induced by the difference between the thermal expansion of the shaft and the glued amorphous ribbons during the glueing process. In this kind of torque sensor, a rotation magnetization model can be used to explain the sensor output characteristics when the compressive bias stress is relatively large.