It is well-known that the regulation
of the phase boundary is an
efficient strategy to boost the piezoelectric performance of perovskite
structure ceramics. However, it is seldomly used in the bismuth-layered
structure high-temperature piezoelectric ceramic research field because
of the lack of an available morphotropic phase boundary (MPB). In
this work, a pseudo-MPB was constructed by the dual introduction of
Ce and Cr ions to the CBN ceramic, which remarkably optimized the
piezoelectricity and ferroelectricity. Furthermore, the Ce and Cr
ions evidently suppressed the oxygen vacancy concentration, leading
to improvements in resistivity and thermal stability. Optimized performances
with a satisfactory piezoelectric coefficient (d
33 ∼ 17 pC/N) and an elevated resistivity (ρ)
of 1.35 × 105 Ω·cm (at 600 °C) were
realized in the Ca0.97Ce0.03Bi2Nb1.985Cr0.015O9 ceramic, accompanied by
a high Curie temperature (T
C ∼
934 °C) and good piezoelectric thermal stability. These results
reveal that the Ca0.97Ce0.03Bi2Nb1.985Cr0.015O9 ceramic could be a prospective
piezoelectric material for sensor applications at high temperatures.
Moreover, this work provides a feasible strategy for optimizing the
piezoelectric performances of the CBN-based ceramics by constructing
the pseudo-MPB.