Prof. Fapeng Yu
Shandong University, China
Title: New progress of piezoelectric crystals for high-temperature sensing
Abstract:
Monitoring
of structural health at high temperatures is required in many industrial
applications, including turbine engines, automotive combustion systems, and
aerospace propulsion systems. With recent scientific and technological
developments, there is a pressing need for high-performance piezoelectric
sensors for in-situ monitoring of the dynamic mechanics of such industrial
systems for feedback control and system optimization, as well as for the
monitoring of the health of structural components for safety improvements.
Extensive
studies have been carried out to design different kinds of vibration sensors
for high-temperature applications, including piezoresistive, capacitive, fiber
optic and piezoelectric sensors. Piezoresistive sensors are less susceptible to
electromagnetic interference than other types of sensors, but they are not
suitable for high-temperature applications due to the inherent temperature
dependence of material resistivity. Capacitive sensors can offer the advantages
of low thermal drift, high resolution, and good noise performance, however,
their use in high-temperature applications is often limited by the low working
temperature (<400oC) and the parasitic capacitance of the sensor
itself. Fiber optic sensors have the advantages of high operating temperature
and high tolerance of electromagnetic interference, but they are complex to
fabricate and require expensive signal processing systems. Piezoelectric
sensors have many advantages over the sensors mentioned above. Firstly, they
usually have simple structures and fast response times. Secondly, they are
robust and long-lasting, even in harsh environments. Last but not least,
external power sources are not an essential requirement for piezoelectric
sensors, which greatly facilitates their application in high-temperature
environments.
In
this report, several kinds of high-temperature piezoelectric crystals (LGS
type, BTS type, and ReCOB type crystals etc.) are introduced and
their potential applications for high-temperature (≥482oC)
sensing are discussed.
Fig.1 Temperature dependence of piezoelectric sensitivity
(a) and the stability (b) of the fabricated high-temperature piezoelectric
vibration sensors
Biography: