Monitoring the thickness of polymer coating by using piezoelectric sensor

The electric impedance of a thin-piezoelectric disc which is linked to its thickness deformation is simulated by using a one-dimensional model. It is shown that the electric impedance of such an element depends on the viscoelastic properties and on the thickness of the medium surrounding the ceramic. The validity of the model is shown by comparing the theoretical and experimental electric impedances of a piezoelectric element placed in different viscoelastic media. An original tool for monitoring the thickness and the viscoelastic properties of polymeric coatings is presented.<>