Elaboration and characterization of potassium niobate tantalate ceramics

In this work three different sintering techniques were used to improve the densification and dielectric properties of K(Nb0.40Ta0.60)O3 (KN40T60) lead-free ceramics. Dense samples were obtained using: (1) conventional sintering in air both with and without sintering aids, (2) two-step sintering and (3) spark-plasma sintering. The Curie temperature ranged between −25 and 25 °C for the tetragonal to cubic phase transition, which depend on the microstructure. As the density of pure KN40T60 ceramics was increased, the large dielectric losses obtained by using a conventional sintering process were significantly reduced and reach suitable values. Improvements in the dielectric behavior and densification of KN40T60 ceramics seemed to be related to the sintering process.