Effects of K Nonstoichiometry in (Bi_0.5K_0.5+x )TiO₃ Ceramics

Abstract

K nonstoichiometry effects in (Bi 0.5 K 0.5+x )TiO 3 (BKT) ceramics were studied with K contents varying in the range of −8≤ x ≤+1 mol% from the stoichiometric K 0.5 . Within the range tested, a single BKT phase region was found to be at −1≤ x ≤+1 mol% and secondary phases started emerging with further K deficiency. Despite the formation of secondary phases, BKT perovskite with tetragonal symmetry was retained at all compositions. For nonstoichiometric BKT perovskite, a composition dependent structure property relation was observed; a decrease in tetragonality (c/a) caused piezoelectric coefficient (d 33 ) enhanced while depolarization temperature (T d ) reduced and vice versa.

A Novel Highly Sensitive NO2 Sensor Based on Perovskite Na0.5+xBi0.5TiO3−δ Electrolyte

“…Among perovskite oxides, sodium bismuth titanate (Na 0.5 Bi 0.5 TiO 3 ) is one of special ABO 3 perovskite-phase oxide which has two atomics (Na and Bi) occupying A site. YS Sung 18, 19 , R Zuo 12 , M Naderer 13 and Li 20, 21 explored the influence of nonstoichiometry upon ion conductivity and doping modification to Na 0.5 Bi 0.5 TiO 3 shows potential in oxide ion conduction. Li 21 also reported that the Mg-doping Na 0.5 Bi 0.49 Ti 0.98 Mg 0.02 O 2.965 exhibited excellent conductivity to ~0.01 S·cm −1 at 600 °C and predicted the possible application in SOFC and sensor field as electrolyte material.…”