Synthesis and characterization of K0.5Na0.5NbO3-BaTiO3-based lead-free piezoelectric ceramics

ANDREA PRADO ESPINOSA; LEANDRO RAMAJO; MIRIAM CASTRO; FERNANDO RUBIO-MARCOS

Foz do Iguazu

Congreso; 7th International Congress on Ceramics; 2018

Sociedad Brasileña de Cerámicos

Lead-based ceramics are widely used piezoelectric materials due to their excellent piezoelectric properties, but they are not environmentally friendly due to lead oxide toxicity. [1] Therefore, a number of studies have been carried out to improve electrical properties of different kind of ABO3 perovskites. [2] In the (1-x)K0.5Na0.5NbO3-xBaTiO3 system the effect of (K,Na) substitution by Ba decreases the temperature of the maximum dielectric permittivity and improves the dielectric properties. Consequently, this kind of materials can be used as an alternative candidate to replace conventional piezoelectric materials [3]. In this work, we present the synthesis and characterization of (1-x)K0.5Na0.5NbO3?xBaTiO3, (x= 0.03, 0.04, 0.05, 0.06, 0.07) based lead-free piezoelectric ceramics through the solid-state reaction route. Powders were mixed in different compositions with the final propose of obtaining extensive applications. It was observed that Ba2+ ions occupy the A sites of the perovskite structure, while Ti4+ ions replace Nb5+ ions at the B sites, resulting in the distortion of the perovskite structure. Additionally, for the highest BaTiO3 concentration a practically constant dielectric constant curve was registered from 20 to 500°C, whereas the loss tangent values were low.