Effects of A-site vacancies and lanthanum aluminate substitution on the dielectric and electromechanical properties of (1−y)Bi0.5+x(Na0.78K0.22)0.5−3xTiO3–yLaAlO3 lead-free ceramics. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Yun, Ji Sun; Park, Jung-Soo; Lee, Ku-Tak; Jeong, Young-Hun; Paik, Jong-Hoo; Cho, Jeong-Ho
• Is Part Of: Ceramics international. Volume 42:Issue 1:Part A(2016)
• Page Start: 1015
• Page End: 1019
• Publication Date: 2016-01
• Subjects: E. Actuator -- Lead free piezoelectric ceramics -- Phase transition -- Electric field-induced strain; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.09.018
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: (1− y )Bi0.5+ x (Na0.78 K0.22 )0.5−3 x TiO3 – y LaAlO3 ( x =0–0.02, y =0–0.01) piezoelectric ceramics were synthesized with a conventional solid state reaction method. The structure and morphology of the (1− y )Bi0.5+ x (Na0.78 K0.22 )0.5−3 x TiO3 – y LaAlO3 ceramics were characterized by XRD (X-ray diffraction) and FE-SEM (field emission scanning electron microscopy). The electric polarization, electric-field-induced strain and temperature-dependence dielectric constant were investigated. These results show that a non-polar phase was induced by changing the proportion of content x to have a deficiency of Na + and K + and excess of Bi 3+ ions. A phase boundary between non-polar and polar (ferroelectric) phases was observed at ambient temperature. The non-polar phase was switched to the polar phase with the application of an electric field. The stability of the induced polar phases strongly depended on the proportion of content x . An enhanced electric-field-induced strain of 0.35% at 6 kV/mm was observed in 0.99Bi0.505 (Na0.78 K0.22 )0.4985 TiO3 –0.01LaAlO3 ( x =0.005, y =0.01) ceramics sintered at 1150 °C for 2 h.