ChemInform Abstract: Processing and Electromechanical Properties of (Bi_0.5Na_0.5) _(1—1.5x)La_xTiO₃ Ceramics.

Abstract

Processingand Electromechanical Properties of (Bi 0.5 Na 0.5 ) (1−−1.5x) LaxTiO 3 Ceramics.-Bi-Na titanate (BNT, Bi 0.5 Na 0.5 TiO 3 ) containing 1-6 at.% La is prepared by a conventional oxide method. Dense ceramics with at least 95 % of the theoretical density are prepared by sintering green pellets at 1050-1150 • C. Small amounts of La 2 O 3 (¡ 2 %) lead to significant improvements in the dielectric, piezoelectric, and electromechanical properties. The BNT-based ceramic with 1 % La doping provides a dielectric constant of 560, a piezoelectric charge constant of 92 pC/N, and a hydrostatic piezoelectric coefficient of 72 pC/N. -(HERABUT, A.; SAFARI, A.; J.

Preparation and Electric Properties of Bi0.5Na0.5TiO3–Bi(Mg0.5Ti0.5)O3 Lead‐Free Piezoceramics

“…The highest small‐signal d 33 can be obtained at x = 0.05 with a value of 110 pC/N. By comparison, it is higher than pure BNT ( d 33 = 58 pC/N) and other BNT‐based ceramics such as 0.9625BNT–0.0375Bi(Zn 0.5 Ti 0.5 )O 3 (92 pC/N) and 0.93BNT–0.05BT–0.02K 0.5 Na 0.5 NbO 3 (KNN) (98 pC/N), but lower than 0.94BNT–0.06BT (155 pC/N) . It is of note that the sintering temperature has a significant influence on the small‐signal d 33 .…”

“…However, it also has a high coercive field ( E C = 7.3 kV/mm), making the poling of ceramics difficult. Thus the BNT ceramics always exhibit weak piezoelectric properties . Doping or substitution is the most popular way to improve piezoelectric properties, and plenty of BNT‐based solid solutions, such as BNT–Bi 0.5 K 0.5 TiO 3 , BNT–NaNbO 3 , Bi 2 O 3 ‐doped BNT, Bi 0.5 (Na 1− x − y K x Li y ) 0.5 TiO 3, BNT–BT–Bi 0.5 Li 0.5 TiO 3 have been developed and studied intensively.…”

Effect of Ba2+ in BNT ceramics on dielectric and conductivity properties

“…But Bi ion is highly volatile at high temperature above 1130℃ during sintering and making this material difficult to pole due to its high conductivity [3]. The solution to this problem has been found by many researchers, who were able to modify BNT crystal by the substitution of other A and B-site cations, such as in (Bi 0.5 Na 0.5 ) (1-1.5x) La x TiO 3 ; (BNLT) [4], BNT-KNbO 3 (KN) [5], and BNT-Ba(Ti,Zr)O 3 [6] solidsolution ceramic system. The piezoelectric properties of these ceramics were significantly improved.…”

Structure and electrical properties of (Na0.5Bi0.5)0.94Ba0.06TiO3 ceramic with 0.5 wt% of MnO

“…The coercive field is usually regarded as the main contributing factor to the piezoelectric properties of NBT based solid solutions [13] . The degradation of piezoelectric constant with the MnO addition can be attributed to the increase of coercive field.…”