Fabrications of the lead-free (Na0.5K0.5)NbO3-CaTiO3 piezoelectric ceramics and their applications on the Surface Acoustic Wave (SAW) Filters

• Main Authors: Yi-Fang Lin, 林義訪
• Other Authors: Sheng-Yuan Chu
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/26287252851488321541

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 94 === Recently, due to the raise of environmental sense many chemical substances such as lead (Pb), cadmium (Cd), mercury (Hg), hexavalent chromium (Cr6+) and so on will be inhibited. PZT is the most common piezoelectric material but it contains lead which causes the environmental pollution problems. Therefore, to develop the substitute is important. The development of the lead-free materials is difficult and present tendency. In this report, we investigated the doping effect by introducing Calcium Titanate (CaTiO3) dopants into (Na0.5K0.5)NbO3 ceramics. The results show that 0.5mol% CaTiO3 doped samples provide large electromechanical planar and thickness coupling coefficients of kp = 38% and kt = 42%. According to the P-E measurements, the coercive field and remanent polarization are 12.2 kV/cm and 12.4 μC/cm2, respectively. In this report, we successfully fabricated the surface acoustic wave filters on the lead-free NKN substrates. The phase velocity is 3238m/s,insertion loss is -36.92db,TCF is -294 ppm/℃ and K2 is 5.37%.