Thick-film strain transducers made using piezoelectric paint

Abstract

This paper describes the manufacture and testing of a novel strain transducer based on piezoelectric paint for use in structural vibration monitoring. This is a form of thick-film sensor, similar in structure to conventional thick-film sensors based on piezoelectric ink. However, the use of paint avoids two problems associated with the ink based manufacturing process: screen printing and high temperature curing. The materials selection and application techniques development are outlined for the three principal components of the transducer: the resin binder, the piezoelectric material and the electrode. The final design comprised a sprayable suspension of milled PZT powder in lacquer (the piezoelectric paint) with a gold electrode formed by physical vapour deposition. The transducers were tested for variability and for dynamic properties (bandwidth and dynamic range). It was found that there is considerable scatter between the output sensitivities of individual transducers, but that the dynamic properties were very consistent. It is shown that the techniques developed form the basis for a viable low cost vibration transducer in the range 20 - 600Hz.