Phase structure, morphology, and Raman characteristics of NaNbO3 particles synthesized by different methods

NaNbO₃ (NN) particles were synthesized by using conventional mixed-oxide (CMO), molten salt synthesis (MSS) and topochemical micro-crystal conversion methods (TMC), respectively. The effects of preparation methods on the phase structure, morphology and Raman characteristics of the NaNbO₃ particles were investigated. The results show that the NN particles prepared by conventional mixed-oxide and molten salt synthesis methods are all of orthorhombic structure in Pbma space group. Furthermore, those particles have equiaxial morphology. The single-crystal NaNbO₃ particles synthesized by the topochemical micro-crystal conversion method are of pseudocubic structure. Moreover, they are of plate-like shape with a high aspect ratio and a high (h 0 0) degree of orientation, which is very promising as template for texturing (K, Na)NbO₃ (KNN) based ceramics. Besides, all the spectra lines in the Raman spectra can be attributed to the internal modes of NbO₆ octahedron, and they prove that the particles synthesized by the different methods have different structure types.