Piezoelectric paints as one approach to smart structural materials with health-monitoring capabilities

Piezoelectric paints have a potential to change a conventional structural material into an intelligent material system with health-monitoring capabilities such as vibration sensing and damage detection. Such paints were prepared using lead zirconate titanate (PZT) ceramic powder as a pigment and epoxy resin as a binder. The obtained paints were coated on aluminum test specimens, and were cured at room temperature or at 150 degrees C, thus farming the paint films having different thicknesses of 25-300 mu m, These films were then poled at room temperature, and were evaluated with regard to the sensitivities as vibration and acoustic emission sensors in the frequency ranges of 0-250 Hz and 0-1.0 MHz, respectively. This paper mainly describes the effects of the film thickness and the cure temperature on the poling behavior of the PZT/epoxy paint film. This paper describes also the application of the paint film as a vibration modal sensor integrated into a structural material.