This study investigates the relationship between the electro-mechanical properties of Cu-doped potassium sodium niobate (KNN) piezoceramics driven at high vibration velocities and their structural origins. Intrinsic and extrinsic contributions to the dynamic strain were quantified at high-power resonance conditions by in-situ high-energy X-ray diffraction. These contributions were correlated to the observed sub-coercive dielectric and piezoelectric responses. Cu doping impairs extrinsic contributions of KNN due to the movement of non–180° domains, akin to acceptor-doped hard PZT, reducing the fraction of transverse strain originating from non–180° domain wall motion over the total strain of 5% at 0.8 m/s. Therefore, the performance of Cu-doped KNN and PZT were found to be comparable. Both systems exhibit a high mechanical quality factor at low vibration velocity, which decreases at high displacement rates. Additionally, the temperature dependence of electromechanical properties for different Cu doping amounts was investigated. In particular, the mechanical quality factor at the vibration velocity of 1 m/s in a temperature range of −40 °C to 140 °C was studied. According to the findings, the composition doped with 0.5% Cu exhibited a stable vibration at 1 m/s, with only 10% variation in the mechanical quality factor between 20 °C and 140 °C.

中文翻译：

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Cu 对 K0.5Na0.5NbO3 压电陶瓷的硬化及其在大功率驱动中的温度依赖性


本研究研究了在高振动速度下驱动的铜掺杂铌酸钾钠 （KNN） 压电陶瓷的机电性能与其结构来源之间的关系。在高功率共振条件下，通过原位高能 X 射线衍射量化了对动态应变的内在和外在贡献。这些贡献与观察到的亚矫顽力介电和压电响应相关。由于非 180° 畴的运动，Cu 掺杂损害了 KNN 的外在贡献，类似于受体掺杂的硬 PZT，在 0.8 m/s 时，减少了非 180° 畴壁运动产生的横向应变在 5% 的总应变中的分数。因此，发现 Cu 掺杂 KNN 和 PZT 的性能具有可比性。两种系统在低振动速度下都表现出高机械质量因数，在高位移率下则会降低。此外，还研究了不同 Cu 掺杂量的机电性能的温度依赖性。特别是，研究了在 −40 °C 至 140 °C 的温度范围内 1 m/s 振动速度下的机械品质因数。根据研究结果，掺杂 0.5% Cu 的组合物在 1 m/s 时表现出稳定的振动，在 20 °C 和 140 °C 之间机械品质因数只有 10% 的变化。