Microstructure,crystalline phase and electrical properties of Li_0.06(Na_0.5K_0.5)_0.94Nb_1-2x/5Mg_xO₃ lead-free piezoelectric ceramics

Hai-tao Li1,2),Bo-ping Zhang1),Qian Zhang1),Peng-peng Shang1),and Gao-lei Zhao1) 1) School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2) School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471003,China

摘 要：MgO-modified Li0.06（Na0.5K0.5）0.94NbO3（L6NKN） lead-free piezoelectric ceramics were synthesized by normal sintering at a relatively low temperature of 1000°C.The crystalline phase,microstructure,and electrical properties of the ceramics were investigated with a special emphasis on the influence of MgO content.The addition of MgO effectively improves the sinterability of the L6NKN ceramics.X-ray diffraction analysis indicates that the morphotropic phase boundary（MPB） separating orthorhombic and tetragonal phases for the ceramics lies in the range of Mg doping content（x） from 0.3at% to 0.7at%.High electrical properties of the piezoelectric constant（d33=238 pC/N）,planar electromechanical coupling coefficient（kp=41.5%）,relative dielectric constant（εr=905）,and remanent polarization（Pr=38.3 μC/cm2） are obtained from the specimen with x=0.5at%,which suggests that the Li0.06（Na0.5K0.5）0.94Nb（1-2x/5）MgxO3（x=0.5at%） ceramic is a promising lead-free piezoelectric material.

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