We report fabrication and piezo- and pyroelectric characterizations of spark plasma sintered (SPS) lead-free K0.5Na0.5NbO3 (KNN) ceramics. SPS sintering produced dense KNN (99% of the theoretical density) at sintering temperature as low as 900°C. A significant improvement in the dielectric, piezoelectric and pyroelectric properties is observed after annealing the sample at 925°C. The measured piezoelectric coefficient d33 and pyroelectric coefficient of poled KNN ceramic are 94 pC/N and 22.84 μCm−2K−1, respectively. These values are high enough to focus on the further enhancement of the material properties through adequate control of the phase structure of the material for lead-free energy harvesting applications.

中文翻译：

---

放电等离子体烧结铌酸钾钠 (KNN) 陶瓷中的压电和热电性

我们报告了放电等离子体烧结 (SPS) 无铅 K0.5Na0.5NbO3 (KNN) 陶瓷的制造以及压电和热电特性。SPS 烧结在低至 900°C 的烧结温度下产生致密的 KNN（理论密度的 99%）。在 925°C 下退火样品后，观察到介电、压电和热电性能的显着改善。测得的极化 KNN 陶瓷的压电系数 d33 和热电系数分别为 94 pC/N 和 22.84 μCm-2K-1。这些值足够高，可以通过充分控制无铅能量收集应用的材料相结构来进一步增强材料性能。