ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 63, (4) 399 - 402 (2019)


EFFECT OF MnO₂ ON THE ELECTRICAL PROPERTIES OF 0.96KNNT-0.04BNZ LEAD-FREE PIEZOELECTRIC CERAMICS
 
Luo Wenqin, Shen Zongyang
 
Energy Storage and Conversion Ceramic Materials Engineering Laboratory of Jiangxi Province, China National Light Industry Key Laboratory of Functional Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, China

Keywords: Lead-free ceramics, Piezoelectric properties, KNN, MnO₂ doping
 

0.96(K0.49Na0.51)(Nb0.97Ta0.03)O₂-0.04Bi0.5Na0.5ZrO₃ + x mol% MnO₂ (0.96KNNT-0.04BNZ + x mol% MnO₂, x=0, 0.1, 0.2, 0.4, 0.6, 0.8) lead-free piezoelectric ceramics were prepared via conventional solid state method. The effect of MnO₂ doping content on the structure and electrical properties of 0.96KNNT-0.04BNZ ceramics was investigated. All samples had pure perovskite structure with coexistence of orthorhombic and tetragonal phases at room temperature. The 0.96KNNT-0.04BNZ + 0.2 mol% MnO₂ ceramic sample exhibited enhanced piezoelectric constant (d33=330 pC/N) and planar electromechanical coupling coefficient (kp=38.8%). In addition to other optimized electrical properties such as medium high dielectric permittivity (εT33/ ε₀ =1370) and mechanical quality factor (Qm=135), relatively low dielectric loss (tanδ=2.4%) and high Curie temperature (Tc=305 ̊C), this ceramic sample should be a promising lead-free alternative to toxic lead-based piezoelectric materials.


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doi: 10.13168/cs.2019.0036
 
 
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