以传统固相法工艺制备(1-x)K0.5Na0.5NbO3-xBaCu0.5W0.5O3[(1-x)KNN-xBCW]无铅压电陶瓷,研究不同BCW掺量(x=0%,0.1%,0.25%,0.5%,1.0%,摩尔分数,下同)对KNN陶瓷的晶体结构和电性能的影响,结果表明:x〈0.5%时,KNN陶瓷的相结构没有改变,仍为正交相钙钛矿结构。与纯KNN陶瓷相比,掺BCW陶瓷的烧结温度降低,相对密度显著提高。引入BCW对KNN陶瓷的电性能有很大影响,其压电常数d33、机电耦合系数kp和机械品质因数Qm均随BCW含量的增加先升高后降低,并在x=0.25%时达到最大值。当x=0.25%时,(1-x)KNN-xBCW陶瓷的相对密度达到98.2%,获得最佳电性能:介质损耗tanδ=0.031,相对介电常数εr=450,d33=128 pC/N,kp=0.40,Qm=201。
(1-x)K0.5Na0.5NbO3-xBaCu0.5W0.5O3[(1-x)KNN-xBCW] lead-free piezoelectric ceramics were fabricated by the traditional solid state reaction method.Crystal structure and electrical properties of K0.5Na0.5NbO3(KNN) ceramics were investigated with dif-ferent BCW contents(x = 0,0.1%,0.25%,0.5%,and 1%,in mole,the same below).Results show that KNN ceramics have an ortho-rhombic perovskite structure after doping with a small amount(x0.5%) of BCW.Sintering temperature of KNN ceramics after dop-ing BCW decreases and relative density increases demonstrably compared with pure KNN.Furthermore,piezoelectric constant d33,electromechanical planar coupling factor kp,and mechanical quality factor Qm increase first and then decrease promptly with the in-crease of BCW contents.The relative density of the sample with x = 0.25% is 98.2% and it exhibits optimal properties: dielectric loss tan δ = 0.031,relative permittivity εr = 450,d33 = 128 pC/N,kp = 0.40,and Qm = 201.