Low-Temperature Synthesis of Nanocrystalline KNbO₃

Abstract

KNbO₃ nanocystalline was synthesized by polymeric precursor method. The effects of amount of CA and EG on the stability of the precursor sol were investigated. The evolution of KNbO₃ crystal phase was also investigated by XRD and TG-DTA. The results show that a homogeneous precursor sol was formed in the case of n(CA):m(metal ion)=3:1 and n(CA):n(EG)=1:2. During the calcinations, K₃Nb₇O₁₉ and K₄Nb₆O₁₇ occurred first and then reacted into KNbO₃. The sintering process largely influences the morphology of the prepared products. As the heat rate is rapid, most of the nanocrystalline is grain-like, while most of the nanocrystalline is rod-like at a slow heating rate. The forming mechanism of different morphologies of the prepared nanocrystalline was also discussed.

Keywords:

• Chemical synthesis
• Citrate
• Ferroelectrics
• Grain
• KNbO₃
• Morphology
• Nanocrystalline
• Nanometer
• Nanorod
• Phase evolution
• Polymeric precursor method
• Powder
• TEM
• TG-DTA
• XRD

ACKNOWLEDGMENT

This work is supported by the National Natural Science Fundation of China (grant No. 50672056, 50432010).