Investigation of factors affecting the preparation of PZT thick films

Many piezoelectric applications require materials with a thickness less than 100 μm. As the manufacturing of bulk ceramics of this thickness is not very easy, thick films were deposited by screen-printing on Ag–Pd-coated alumina substrates. Deposits were about 80 μm thick. Thick films were prepared from a PZT powder and an organic vehicle. The following studies on preparation of the layers were carried out: (1) influence of the powder preparation process (dry or wet route) upon the ink quality and piezoelectric characteristics of thick films; (2) part played by two different dispersing agents in the improvement of ink composition; and (3) flux addition as PbO–PbF2 and Bi2O3–B2O3–CdO, to lower sintering temperatures while maintaining good piezoelectric coefficients. A comparison of d31 and dh coefficients for bulk and thick films is given.