Processing and Sintering of Sodium-potasium Niobate–based Thick Films

The electrophoretic deposition (EPD) and sintering of (K 0.5 Na 0.5) 0.99 Sr 0.005 NbO 3 (KNNSr) thick films on platinized alumina substrate is reported. We demonstrate that by a two-step deposition-sintering the KNNSr films thicker than 30 μm without defects can be prepared. The effect of the sintering time on structural, microstructural, dielectric and electromechanical characteristics of the KNNSr thick films is discussed. By increasing the sintering time from 2 to 4 hours, the density and the dielectric permittivity of the thick films increased. The unit cell parameters of the perovskite phase decreased which could be related to the formation of polyniobate and volatilization of akalies. Processed KNNSr exhibited promising electromechanical and piezoelectric properties, with a thickness coupling factor up to 35 % and piezoelectric coefficient d 33 up to 80 pC/N