A capacitance ultrasonic transducer for high-temperature applications.
This paper introduces a novel ultrasonic capacitance transducer for operation at elevated gas temperatures of several hundred degrees Celsius. The transducer design is based on a metallic membrane foil and a backplate made of an electrically conducting substrate coated with an insulation layer. Guidelines are given for selecting suitable materials for the membrane foil, the backplate substrate, and the coating. Manufacturing techniques applied for fabrication of different transducer types are described in detail. Transducers tested were composed of titanium substrates with insulation layers of silicon nitride or of silicon substrates with silicon oxide coatings. Experimental setup and test procedures are described. Results of transducer characterization and performance tests at elevated temperatures are presented and discussed. Transducer functionality is proven for air temperatures of up to 500 degrees C.
Schröder
Andreas
A
Institute of General Physics, Vienna University of Technology, A-1040 Wien, Austria.
Harasek
Stefan
S
Kupnik
Mario
M
Wiesinger
Michael
M
Gornik
Erich
E
Benes
Ewald
E
Gröschl
Martin
M