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.