Nb self‐doped Bi₃Ti_1‐xNb_1+xO₉ (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1) high‐temperature piezoelectric ceramics were fabricated through the conventional solid‐state sintering method. The effects of different Nb self‐doping levels on the microstructure, piezoelectric activities, and electrical conduction behaviors of these Nb self‐doped Bi₃Ti_1‐xNb_1+xO₉ ceramics were studied in detail. Large doping level effects on piezoelectric activity and resistivity were confirmed, which might be ascribed to the evolution of the crystal structure and the variations of the oxygen vacancy concentration and the grain anisotropy induced by Nb doping. An optimized piezoelectric coefficient (d₃₃) of 11.6 pC/N was achieved at x = 0.04 with a Curie temperature of 906°C. Additionally, an improved DC resistivity of 6.18 × 10⁵ Ω·cm at 600°C was acquired in this ceramic. Furthermore, the ceramic exhibited excellent thermal stability with the d₃₃ value maintaining 95% of its initial value after being annealed at 850°C for 2 hours. These results showed that Nb self‐doped Bi₃Ti_1‐xNb_1+xO₉ ceramics might have great potentials for high‐temperature piezoelectric applications.

中文翻译：

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Nb自掺杂Bi3TiNbO9高温压电陶瓷的掺杂能级效应

Nb自掺杂的Bi ₃ Ti _{1- x} Nb _{1+ x} O ₉（x  = 0、0.02、0.04、0.06、0.08和0.1）是通过常规的固态烧结方法制造的。不同Nb自掺杂水平对这些Nb自掺杂Bi ₃ Ti _{1‐ x} Nb _{1+ x} O ₉的微观结构，压电活性和导电行为的影响对陶瓷进行了详细的研究。证实了掺杂水平对压电活性和电阻率的较大影响，这可能归因于Nb掺杂引起的晶体结构的演变以及氧空位浓度和晶粒各向异性的变化。在x  = 0.04且居里温度为906°C的情况下，获得了11.6 pC / N的最佳压电系数（d ₃₃）。另外，一种改进的DC的6.18×10电阻率⁵ Ω·cm的在600℃下在该陶瓷获取。此外，d ₃₃陶瓷表现出优异的热稳定性。在850℃下退火2小时后，其值保持其初始值的95％。这些结果表明，Nb自掺杂的Bi ₃ Ti _{1 x x} Nb _{1+ x} O ₉陶瓷在高温压电应用中可能具有很大的潜力。