采用熔盐法分别采用KCl，K2SO4，K2CO3或KNO3为熔融盐和Nb2O5反应，900 ℃下反应2 h合成了铌酸钾晶体。研究了熔融盐的种类对产物组成、形貌和光学性能的影响。X射线衍射检测结果表明分别采用KCl和K2SO4 为熔融盐时的产物为KNb3O8，而采用K2CO3和KNO3为熔融盐时得到的产物为K3NbO4。电子扫描显微镜检测结果表明采用KCl为熔融盐时产物为0.2~0.5 μm宽，1~10 μm长的棒状结构，采用K2SO4为熔融盐时，产物为0.2~1 μm宽，1~25 μm长的棒状结构。采用K2CO3为熔融盐时，产物不是棒状结构,而是不规则颗粒状结构。采用KNO3为熔融盐时，产物为0.2~1 μm宽的棒状结构，长度为0.5~4 μm，部分棒连接在一起。荧光光谱研究表明，以K2SO4，K2CO3和KNO3为熔融盐制备的样品具有非常相似的荧光光谱，以KCl，K2SO4和K2CO3为熔融盐制备的样品具有较好的荧光性。

Potassium niobate crystals have been synthesized by a molten salt process with KCl, K2SO4, K2CO3 or KNO3 as molten salt reactive Nb2O5 materials at 900 ℃ for 2 h. The effect of different kinds of molten salt on the structure and morphological profile of the powers were discussed, and the optical properties of the samples were studied. X-ray diffraction results showed that the product is KNb3O8 when the KCl and K2SO4 as molten salt, respectively, and the product is K2NbO4 when the K2CO3 and KNO3 as molten salt, respectively. Scanning electron microscopy results showed that bar was formed with the width of 0.2~0.5 μm and the length of several microns. Using K2SO4 as molten salt, the width of rod is 0.2~1 μm and the length is 1~25 μm. Using K2CO3 as molten salt, the product is not rod-like structure, but irregular granular structure. Using KNO3 as molten salt, the width of rod is 0.2~1 μm and the length is 0.5~4 μm. Part of the rod-like structure connected together. Fluorescence spectra showed that KNb3O8 and K3NbO4 crystals have good fluorescence. Fluorescence studies have shown that the samples have very similar fluorescence spectra with K2SO4, KNO3 and K2CO3 as the molten salt. The samples have good fluorescence which were prepared using KCl, K2SO4 and K2CO3 as molten salt.