本研究主要在開發無鉛壓電陶瓷(1-x)(Na0.535K0.48)NbO3－xLiNbO3（NKLN），針對材料的相轉換、燒結溫度以及極化條件作一系列的探討。以鋰添加鈮酸鈉鉀陶瓷中發現斜方相-正方相(orthorhombic-tetragonal)轉換的MPB其實還含有單斜方相的存在。在x=0.05時，NKLN陶瓷可獲得最佳的壓電特性：kp = 42%、kt = 52%。0.95(Na0.535K0.48)NbO3－0.05LiNbO3陶瓷在不同的燒結溫度下，其燒結溫度最低可降至900oC，但燒結溫度仍以950oC為佳，並在此燒結溫度下進行不同燒結時間的研究，在950oC燒結4小時，可獲得最佳機電耦合係數kp = 48%、kt = 52%。此研究中還探討了壓電陶瓷在不同之極化條件下對電特性之影響，由結果中發現，極化溫度會大幅影響電特性，當極化溫度在90oC、極化電場為3kV/mm時將獲得最佳極化效果。
　　在一系列的研究中找出最佳特性之陶瓷體後，將此陶瓷應用於製作超音波換能器，並計算陶瓷體和背向層(backing layer)的聲阻值，分別以0.95(Na0.535K0.48)NbO3－0.05LiNbO3和(Na0.5K0.5)NbO3進行pulse/echo脈衝回聲響應的檢測，比較其輸出信號的差異，探討壓電陶瓷之壓電特性在超音波換能器上的影響。

In this study, the development of lead-free (1-x)(Na0.535K0.48)NbO3－xLiNbO3 (NKLN) ceramics were investigated and the phase transition behavior of material, sintering temperature and poling condition were discussed. In NKLN ceramics, it was observed that the morphotropic phase boundary (MPB) not only contented the orthorhombic and tetragonal phases, but also had the formation of monoclinic phase. The best piezoelectric properties of NKLN ceramics with kp = 42%、kt = 52% were obtained at x = 0.05. In 0.95NKN-0.05LN ceramics, the sintering temperature was reduced from 1050oC to 900oC and the excellent piezoelectric properties were obtained under sintering at 950oC. Moreover, the 0.95NKN-0.05LN ceramics sintered at 950oC for different soak times was also investigated. The maximum values of kp (48%) and kt (52 %) were obtained at the optimum soak time of 4 h. In the present study, the electric properties of ceramics were significantly by the poling conditions, including poling temperature and poling electric field. The optimum poling conditions obtained were under the poling temperature of 90oC and poling electric field of 3 kV/mm.
　　Based on the properties of ceramics above, the ceramics with high kp and kt values were chose for fabrication of single-element ultrasound transducers. The acoustic impedances of the ceramics and backing layer were calculated. The pulse/echo response of the ultrasound transducers fabricated using the (Na0.5K0.5)NbO3 and 0.95(Na0.535K0.48)NbO3- 0.05LiNbO3 ceramics were examined and the performances of these two ultrasound transducers were compared. Effects of piezoelectric properties of ceramics on the performances of ultrasound transducer were also investigated.

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