Preparation of nano-crystalline potassium lithium niobate powders by the polymeric precursor method

In this work, the polymeric precursor method was used to synthesize nanocrystalline potassium lithium niobate powders (K₃Li_2-xNb_5+xO_15+2x, KLN). Citric acid was used as the chelating agent to complex with the metal cations. Water was used as the solvent and ethylene alcohol was used to promote the polymerization degree of the solution. The precursor gel on calcination at 900°C for 2 h produces a pure K₃LiNb₆O₁₇ phase and the corresponding average particle size is 30-50 nm. The influences of the pH value, the molar ratio of citric acid: metal cations and citric acid:ethylene alcohol on the formation of homogeneous K-Li-Nb precursor gels are also studied. The results show that a homogeneous K-Li-Nb precursor gel with no precipitate is formed at pH = 8, the optimum molar ratio of citric acid:metal cations is 3, and citric acid:ethylene alcohol is 2.