Properties of (Na0.5K0.5)NbO3–SrTiO3 based lead-free ceramics and surface acoustic wave devices

Lead-free (1 − x)[(Na0.5K0.5)NbO3]–xSrTiO3 ceramics, where x = 0–3 mol%, have been prepared by the conventional mixed oxide method in this paper. All of the SrTiO3 doped (Na0.5K0.5)NbO3 specimens do not deliquesce as exposed to water for a long time. The samples are characterized by X-ray diffraction analysis, scanning electron microscopy, and atomic force microscopy measurements. The dielectric, piezoelectric and ferroelectric properties are also investigated. Our results show that the addition of SrTiO3 is very effective in preventing the deliquescence and in improving the electric properties of (Na0.5K0.5)NbO3 ceramics. Finally, surface acoustic wave devices based on lead-free ceramics have been successfully fabricated and their characterization is presented.