Papers by Keyword: Piezoelectric Property

Abstract: (Na_0.5K_0.5)NbO₃ with 0~5 mole% Bi_0.5(Na_0.95K_0.05)_0.5TiO₃ has been prepared following the conventional mixed oxide process. It can be concluded that the NKN-BNKT ceramics have orthorhombic structures in the case x≤ 0.02. With increasing BNKT content (x=0.03 to 0.05), however, the structure changes from orthorhombic to rhombohedral phase. Above results demonstrated that the MPB between orthorhombic and rhombohedral phases exits in the solid solution with the BNKT content of x=0.02. For 0.98(Na_0.5K_0.5)NbO₃-0.02Bi (Na_0.95K_0.05)TiO₃ ceramics, the electromechanical coupling coefficients of the planar mode k_p and the piezoelectric constant d₃₃ reach 0.28 and 155 p/CN, respectively, at the sintering of 1100 °C for 3 h. Dielectric and piezoelectric properties have maximum values at the sintering temperature of 1100 °C for 5 h. For 0.98(Na_0.5K_0.5)NbO₃-0.02Bi_0.5(Na_0.95K_0.05)_0.5TiO₃ ceramics, the electromechanical coupling coefficients of the planar mode k_p and the piezoelectric constant d₃₃ reach 0.30 and 170, respectively, at the sintering of 1100 °C for 5 h. The effect of prolonging the sintering time to the 0.98(Na_0.5K_0.5)NbO₃-0.02Bi_0.5(Na_0.95K_0.05)_0.5TiO₃ system is a helpful method on ceramic processing to improve densification and properties..

Abstract: 1-3 piezoelectric-damping composites were fabricated using piezoelectric ceramic as functional filler and epoxy resin as matrix by cut-filling method. The fabrication procedure of the composites was introduced. The effect of ceramic volume fraction on the damping behavior and the piezoelectric strain factor d₃₃ were studied. The results show that the damping property was firstly improved, and then decreased with the increase of the ceramic volume fraction. An optimal ceramic volume fraction of 15% was shown. TA increased from 29.78 to 32.34. The piezoelectric strain factor d₃₃ reached 323pC·N^-1.

Abstract: In the present study, various quantities of Bi₂O₃ were added into 0.98(Na_0.5K_0.5)NbO₃-0.02Bi(Na_0.93K_0.07)TiO₃ (0.98NKN-0.02BNKT) ceramics. It was found that 0.98NKN-0.02BNKT with the addition of 0~0.5 wt.% Bi₂O₃ exhibit relatively good piezoelectric properties. For 0.98NKN-0.02BNKT ceramics, the electromechanical coupling coefficients of the planar mode k_p and the thickness mode k_t reach 0.40 and 0.47,respectively. For 0.98NKN-0.02BNKT ceramics with the addition of 0.3 wt.% Bi₂O₃, the electromechanical coupling coefficients ofthe planar mode k_p and the thickness mode k_t reach 0.50 and 0.53, respectively. It is obvious that 0.98NKN-0.02BNKT solid solution ceramics by adding low quantities of Bi₂O₃ is one of the promising lead-free ceramics for electromechanical transducer applications.