无铅压电陶瓷KNN常压烧结及其电学性能

用常压烧结法制备K_0.5Na_0.5NbO₃陶瓷。研究烧结温度与陶瓷密度和电学性能的关系。研究表明在1065℃~1120℃范围内, 温度对陶瓷的密度有显著影响。当烧结温度为1100℃时, 密度达到4.35 g/cm³ (占理论密度的95%); 1100℃烧结的陶瓷表现出最好的电学性能, 压电常数最大118 pC/N, 相对介电常数最大达538, 介电损耗最小仅4.7%, 剩余极化强度为15.37 μC/cm², 矫顽场为13.16 kV/cm。陶瓷样品在206℃从正交结构转变到四方结构, 居里温度为410℃。

Electrical Properties of K0.5Na0.5NbO3 Lead-free Piezoceramics by Pressureless Sintering

Lead-free piezoceramics K_0.5Na_0.5NbO₃ were prepared by pressureless sintering. The effects of sintering temperature on the density and electrical properties of KNN ceramics were investigated. The results show that the density of the KNN ceramics changes dramatically in a narrow temperature range of 1065-1120℃. The density of the ceramic sintered at 1100℃ reaches 4.35 g/cm³ (95% of the theoretical density). The ceramic sintered at 1100℃ shows the best electrical properties: the maximum piezoelectric coefficient of about 118 pC/N, the maximum relative dielectric constant of 538, the minimum dielectric loss of 4.70%, the remanent polarization of 15.37 μC/cm² and the coercive electric field of 13.16 kV/cm. The phase transformation temperature from orthorhombic to tetragonal is about 206℃, and the Curie temperature is 410℃.