| The (Na0.5K0.5)NbO3 lead free piezoelectric ceramics was prepared and its powder was calcined by molten salt synthesis and the influence of molten salt contents and the synthesizing temperature were studied,the best processing parameters was conformed: the ratio of molten salt content and raw material was 8wt% and synthesizing temperature is 800℃for 2h.The effect of Sb5+ and Li+ substituting content on the piezoelectric, dielectric and electromechanical properties of sodium potassium niobate lead free piezoelectric ceramics was also studied and its result provided the foundation for the further experiments. The results show that when Sb5+ substituting content is 8mol% and sintering temperature is 1100℃,good comprehensive properties can be obtained; when Li substituting content is 6mol%and sintering temperature is 1100℃,which is located in morphotropic phase boundary (MPB), good dielectric and piezoelectric properties can be observed: Sb5+ and Li+ substituting sodium potassium niobate lead free piezoelectric ceramics all exhibit relaxor behavior;Finally the properties of (Na0.5K0.5)0.94Li0.06(Nb0.92Sb0.08)O3 ceramics and the effect of CuO was studied. It was found that the densification of Sb5+ and Li+ co-doped sample was enhanced, relaxor behavior was weakened and the performance was improved.The scanning electronic microscope (SEM) and X-ray diffraction (XRD) were applied to analyze microstructure and phases, respectively. The differences between solid phase reaction and molten salt synthesis and the effect of sintering temperature on the performance of NKN ceramics were investigated. |
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