Evaluation of Microstructure and Electrical Properties in (Na,K)NbO3-Based Pb-free Piezoelectrics Doped with Various Cu2O Concentration

(Na,K)NbO3계 무연 압전체에서 Cu2O 첨가물의 농도 변화에 따른 미세구조 및 전기적 특성 평가

  • Lee, Youn-Ki (Department of Materials Engineering/ReSEM, Chungju National University) ;
  • Ryu, Sung-Lim (Department of Materials Engineering/ReSEM, Chungju National University) ;
  • Kweon, Soon-Yong (Department of Materials Engineering/ReSEM, Chungju National University)
  • 이윤기 (충주대학교 신소재공학과/친환경에너지 부품소재센터) ;
  • 류성림 (충주대학교 신소재공학과/친환경에너지 부품소재센터) ;
  • 권순용 (충주대학교 신소재공학과/친환경에너지 부품소재센터)
  • Received : 2011.10.10
  • Accepted : 2011.10.24
  • Published : 2011.11.01


The $(Na_{0.52}K_{0.44})(Nb_{0.9}Sb_{0.06})O_3-0.04dLiTaO_3$ (NKNS-LT) ceramics with various $Cu_2O$ concentration were prepared by the conventional solid state reaction method. The $Cu_2O$ content was varied in the range of 0.1~0.4 wt%. The effects of Cu on microstructure, crystallographic phase transition, and piezoelectric properties were investigated. The material with perovskite structure had a tetragonal phase (T1) when $Cu_2O$ concentration was less than 0.3 wt% and it transformed to another tetragonal phase (T2) when the $Cu_2O$ amount was greater than 0.3 wt%. The phase boundary between T1 and T2 phases appeared at around 0.3 wt% of $Cu_2O$ concentration. The piezoelectric properties were shown the maximum values at the composition of the phase boundary. The electro-mechanical coupling factor ($k_p$) was 0.42 and the piezoelectric charge constant ($d_{33}$) was 245 pC/N at the 0.3 wt% of $Cu_2O$ concentration.


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