水热-溶剂热法合成(K,Na)NbO_3无铅压电陶瓷及其性能测试

Hydrothermal Solvothermal Synthesis of (K,Na)NbO_3 Lead-free Piezoelectric Ceramics and Its Properties

通过添加异丙醇利用水热溶剂热法合成了(K,Na)NbO3无铅压电陶瓷粉体.研究了矿化剂浓度、反应物浓度对产物晶相、粒径大小、形貌以及化学组成等的影响.利用X射线衍射仪、傅立叶变换红外吸收光谱以及扫描电子显微镜对所得粉体进行了表征.随后,利用合成的(K,Na)NbO3无铅压电陶瓷粉体,按照传统固相烧结工艺烧制压电陶瓷,并研究了其压电性能.实验结果表明:通过添加异丙醇有机溶剂,可以在矿化剂浓度为2mol/L的条件下合成出纯钙钛矿结构的(K,Na)NbO3粉体.随着反应溶液中K离子含量的增加,产物中离子K的含量也在增加.组成为K0.22Na0.78NbO3样品的压电常数d33高达120 pC/N,与传统固相合成法获得的(K0.5,Na0.5)NbO3常压烧结得到的陶瓷性能相当.由此可预见利用水热溶剂热法合成的(K0.5,Na0.5)NbO3粉体烧结的陶瓷可获得更高的电学性能.

Hydrothermal-solvothermal method was used to synthesize （K, Na）NbO3 powders with the addition of isopropanol. The influence of mineralizer concentration, reactive materials concentration on the phase, particle size, morphology and chemical composition of the products were investigated. The obtained powders were characterized by X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） and scanning electron microscope （SEM）. Then, the obtained （K, Na）NbO3 powders were used to fabricate lead-free piezoelectric ceramics using the traditional sintering process, and its piezoelectric property was also studied. The results indicate that the pure （K, Na）NbO3 powders with perovskite structure were successfully synthesized by hydrothermal-solvothermal method with the mineralizer solution concentration of 2mol/L and the addition of isopropanol. With increase of K^＋ content in the starting solutions, K＋ content in the products also increased. The K/（K＋Na） molar ratio in the products is lower than that in the staring solutions. Moreover, the specimen with the composition of K0.22Na0.78NbO3 exhibites high piezoelectric constant up to d33 = 120 pC/N, which is equivalent with the specimen of （K0.5,Na0.5）NbO3 synthesized by traditional solid-state reaction method. Therefore, it can be forecasted that the （K0.5,Na0.5）NbO3 ceramic sintered from the powders synthesized by hydrothermal-solvothermal method will acquire higher piezoelectric property.