Application of CIP processing and sol-gel surface coating to PZN-PZT piezoelectric ceramics for use as energy harvesters

Piezoelectric 0.2Pb(Zn1/3Nb2/3)O3-0.8Pb(Zr1/2Ti1/2)O3 (PZN-PZT) ceramics in disc form were fabricated and characterized for use as energy harvester devices. A powder mixture with an average particle size of about 1 μm with the addition of 0.5 wt% ZnO was used to obtain a high piezoelectric coefficient and low sintering temperature. A molding method, including cold isostatic pressing (CIP), was used to resolve the cracking and bending problems of thin ceramics during the high-temperature post-processing sintering step. A sol-gel surface coating was found to be very effective for ceramic discs with a very high piezoelectric constant d33 of 536 pC/N. The results of this study could be applicable to small piezoelectric energy harvester devices.