New High Temperature Morphotropic Phase Boundary Piezoelectrics Based on Bi(Me)O₃–PbTiO₃ Ceramics

Abstract

New morphotropic phase boundary (MPB) piezoelectrics, with ferroelectric phase transition (T c ) exceeding that of PbZrO 3 -PbTiO 3 (PZT), were investigated. Based on a perovskite tolerance factor-T c relationship, new high T c MPB systems were projected in the Bi(Me)O 3 -PbTiO 3 system, where Me is a relatively large B +3 -site cation. For the (1 − x)BiScO 3 -(x)PbTiO 3 solid solution, a MPB was found at x-0.64 separating the rhombohedral and tetragonal phases, with correspondingly enhanced dielectric and piezoelectric properties. A transition temperature T c of ∼ 450 • C was determined with evidence of T c 's on the order of ≥ 600 • C in the BiInO 3 and BiYbO 3 analogues, though issues of perovskite stability remain for the smaller tolerance end-member systems.

The effect of alkali niobate addition on the phase stability and dielectric properties of Pb(Zn1∕3Nb2∕3)O3 based ceramic

“…9, the T max of 85PZN-5PT-10RN ͑100-105°C͒ was higher than that of 85PZN-5PT-10BT ͑53°C͒. 4 T max increased and the dielectric dispersion with the measuring frequency decreased with increasing the PT content. These observations were more pronounced in PZN-PT-NN, which can be explained as following.…”

“…When the PT makes the solid solution, the lower tolerance factor of the counterpart material increases the T max at the MPB. 5,20 Combined experiments with the first principle calculations on Pb based solid solutions have shown that T max is proportional to the square of Pb and B-cation displacement since coupling between nearest-neighboring ferroelectrically active cations increases. 21,22 Small tolerance values indicate that the cations partially fill an A site and there is an empty space in the A site, as shown in Eq.…”

“…2,3 To synthesize the PZN based ceramics, other perovskite materials such as BaTiO 3 ͑BT͒ and SrTiO 3 ͑ST͒ are added as phase stabilizers. 4,5 The stabilization of PZN by partially substituted BT and ST was explained using tolerance factor or electronegativity difference. To make the perovskite structure stable, the former is required to be within proper value of ionic radius for the perovskite structure and the latter is required for strong ionic bond.…”

Сегнетоэлектрические релаксорные свойства образцов системы (1-2x)BiScO-=SUB=-3-=/SUB=-· xPbTiO-=SUB=-3-=/SUB=-· xPbMg-=SUB=-1/3-=/SUB=-Nb-=SUB=-2/3-=/SUB=-O-=SUB=-3-=/SUB=- (0.30≤ x≤0.46)

“…Керамика твердых растворов (1 − x)BiScO 3 · xPbTiO 3 (BS−PT) со структурой перовскита с составами близкими к морфотропной фазовой границе (МФГ) между их ромбоэдрической и тетрагональной фаза-ми (x = 0.64), характеризуется пьезомодулями d 33 ∼ ∼ 400 pC/N [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], сопоставимыми по величине с пьезо-модулями цирконата-титаната свинца (ЦTС) -широко используемой пьезокерамики [17][18][19]. При этом точка Кюри керамики BS−PT (T c ∼ 720 K) превышает T c ЦТС на ∼ 100 K, что позволяет повысить температурный диапазон ее использования.…”

High temperature lead-free relaxor ferroelectric: Intergrowth Aurivillius phase BaBi2Nb2O9–Bi4Ti3O12 ceramics

“…15,16 Recently, a qualitative relationship between perovskite tolerance factor and the Curie point ͑T c ͒ at the MPB in PbTiO 3 based systems was proposed. 11,[17][18][19] In general, the smaller the tolerance factor of the non-PbTiO 3 end member, the higher T c at the MPB. 14,20 Guided by this relationship, low tolerance factor bismuth perovskite compounds with PbTiO 3 have been shown to be promising candidates for new, lead-free or lead reduced, high T m RFEs.…”