Piezoelectric characteristics of PNN-PZT/Epoxy paint sensor according to the poling conditions

This paper deals with piezoelectric characteristics according to the poling condition in order to improve the disadvantage of conventional poling treatment and find optimal poling condition for the paint sensor. The paint sensor is composed with PNN-PZT (Pb(Nb,Ni)O3-Pb(Zr,Ti)O3) powder and epoxy resin by 1:1 wt percent (12.2:87.8 vol fraction) in order to reduce the cost and weight. The specimen was made up by using steel mold to get a uniform size, and the dimensions of the paint sensor are 20 × 10 × 1.0 mm3. The poling treatment has been carried out under controlled conditions of the electric field and the poling time, while the poling temperature has been fixed at the room temperature. The output voltage from the paint sensor and the force from the impact hammer were measured by DAQ device (NI, PXI-6259) in order to measure the piezoelectric sensitivity, when the impact hammer hits the paint sensor by using impact device. The piezoelectric sensitivity defined comparing a paint sensor output voltage with impact force and piezoelectric properties by suggested equation for the paint sensor. The analysis of variance was performed to check the main effect and interaction effect on the sensitivity. In conclusion, the poling time affects the sensitivity more than poling electric field. The optimal poling condition of the paint sensor was obtained that the poling time is 30 min, and the electric field is 4 kV/mm at room temperature in the air.