摘要：壓電陶瓷是一類極為重要的功能材料，目前全球在大量使用的壓電陶瓷材料仍是含鉛的壓電陶瓷。含鉛壓電材料在燒結過程中產生的有毒氧化鉛會造成了嚴重的污染問題。(Na0.5K0.5)NbO3（NKN）無鉛壓電陶瓷因為具有優良的壓電效應和鐵電性能，作為有前途的無鉛材料候選材料之一得到廣泛研究。本實驗以0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3（PMN-PT）單晶為模板，通過固相反應法，常壓燒結制備1mol% CuO摻雜的(1-x)(Na0.5K0.5)NbO3-xAB陶瓷，研究CuO摻雜、第二組元、燒結溫度對NKN基陶瓷的結構、介電、壓電、鐵電性能的影響。XRD測量表明，CuO摻雜的0.95Na1/2K1/2NbO3-0.05CaTiO3（0.95NKN-0.05CT）和0.95Na1/2K1/2NbO3-0.05LiSbO3（0.95NKN-0.05LS）陶瓷呈現四方鈣鈦礦結構。不同溫度燒結的陶瓷中都出現一定量的雜相。CuO摻雜的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷呈現寬化、彌散的介電響應峰，頻率色散現象明顯。CuO摻雜的0.95NKN-0.05LS陶瓷的居里溫度TC比CuO摻雜的0.95NKN-0.05CT陶瓷高得多。CuO摻雜的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷呈現對稱、飽和的電滯回線（1020℃燒結除外）。1030℃燒結的CuO摻雜的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷的壓電性能最好，壓電應變常數d33值分別為75.3和110.8pC/N。1020℃燒結的CuO摻雜的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷的Kp值最大，分別為0.4618和0.3103。

關鍵詞：(Na0.5K0.5)NbO3；PMN-PT單晶模板；鈣鈦礦結構；電學性能

Abstract:Piezoelectric ceramics are one of the most important functional materials. At present，the piezoelectric ceramics widely used are still lead-based piezoelectric ceramics, in which the generation of toxic PbO during the sintering process creates serious pollution problems. Recently, much research has focused on the (Na0.5K0.5)NbO3 (abbreviated as NKN) system lead-free piezoelectric ceramics as one of the promising candidate lead-free materials due to its large piezoelectric response and strong ferroelectricity. In this work, 1mol% CuO-doped (1-x)(Na0.5K0.5)NbO3-xAB ceramics were prepared by the conventional solid-state reaction method using the 0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 (PMN-PT) single crystal as a template. The effects of CuO dopant, second component and sintering temperature on the phase structure, dielectric, piezoelectric and ferroelectric properties were studied. The sintered CuO-doped 0.95Na1/2K1/2NbO3-0.05CaTiO3 (0.95NKN-0.05CT) and 0.95Na1/2K1/2NbO3-0.05LiSbO3 (0.95NKN-0.05LS) ceramics exhibit tetragonal perovskite structure, but with slight content of impurity. The CuO-doped 0.95NKN-0.05CT and 0.95NKN-0.05LS ceramics exhibit broad and diffused dielectric response peaks accompanied by apparent frequency dispersion. The Curie temperature TC of the CuO-doped 0.95NKN-0.05LS ceramics is far higher than that of the CuO-doped 0.95NKN-0.05CT ceramics. The CuO-doped 0.95NKN-0.05CT and 0.95NKN-0.05LS ceramics exhibit saturated and symmetric P-E hysteresis loops except sintering at 1020℃. 1030℃-sintered CuO-doped 0.95NKN-0.05CT and 0.95NKN-0.05LS ceramics exhibit excellent piezoelectric properties, in which the values of d33 are 75.3 and 110.8pC/N, respectively. 1020℃-sintered CuO-doped 0.95NKN-0.05CT and 0.95NKN-0.05LS ceramics exhibit the largest electromechanical coupling coefficient Kp, being 0.4618 and 0.3103, respectively.

Keywords: NKN; PMN-PT single crystals template; perovskite structure; electrical preperties