摘要：压电陶瓷是一类极为重要的功能材料，目前全球在大量使用的压电陶瓷材料仍是含铅的压电陶瓷。含铅压电材料在烧结过程中产生的有毒氧化铅会造成了严重的污染问题。(Na0.5K0.5)NbO3（NKN）无铅压电陶瓷因为具有优良的压电效应和铁电性能，作为有前途的无铅材料候选材料之一得到广泛研究。本实验以0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3（PMN-PT）单晶为模板，通过固相反应法，常压烧结制备1mol% CuO掺杂的(1-x)(Na0.5K0.5)NbO3-xAB陶瓷，研究CuO掺杂、第二组元、烧结温度对NKN基陶瓷的结构、介电、压电、铁电性能的影响。XRD测量表明，CuO掺杂的0.95Na1/2K1/2NbO3-0.05CaTiO3（0.95NKN-0.05CT）和0.95Na1/2K1/2NbO3-0.05LiSbO3（0.95NKN-0.05LS）陶瓷呈现四方钙钛矿结构。不同温度烧结的陶瓷中都出现一定量的杂相。CuO掺杂的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷呈现宽化、弥散的介电响应峰，频率色散现象明显。CuO掺杂的0.95NKN-0.05LS陶瓷的居里温度TC比CuO掺杂的0.95NKN-0.05CT陶瓷高得多。CuO掺杂的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷呈现对称、饱和的电滞回线（1020℃烧结除外）。1030℃烧结的CuO掺杂的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷的压电性能最好，压电应变常数d33值分别为75.3和110.8pC/N。1020℃烧结的CuO掺杂的0.95NKN-0.05CT和0.95NKN-0.05LS陶瓷的Kp值最大，分别为0.4618和0.3103。

关键词：(Na0.5K0.5)NbO3；PMN-PT单晶模板；钙钛矿结构；电学性能

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