Piezoelectric, ferroelectric and dielectric properties of La2O3-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free ceramics

✍ Scribed by Peng Fu; Zhijun Xu; Ruiqing Chu; Wei Li; Guozhong Zang; Jigong Hao

• Publisher: Elsevier Science
• Year: 2010
• Weight: 757 KB
• Volume: 31
• Category: Article
• ISSN: 0261-3069
• DOI: 10.1016/j.matdes.2009.07.056

✦ Synopsis

La 2 O 3 (0-0.8 wt.%)-doped (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (abbreviated as BNBT6) lead-free piezoelectric ceramics were synthesized by conventional solid-state reaction. The influences of La 2 O 3 on the microstructure, the dielectric, ferroelectric and piezoelectric properties of the composites were investigated. X-ray diffraction (XRD) patterns indicate that 0.2-0.8 wt.% of La 2 O 3 has diffused into the lattice of BNBT6 ceramics. Consequently, a pure perovskite phase is formed. SEM images show that the microstructure of the ceramics is changed with the addition of a small amount of La 2 O 3 . The temperature dependence of the relative dielectric constant shows that Curie point decreases with the increase of La 2 O 3 . At room temperature, the ceramics doped with 0.6 wt.% La 2 O 3 show superior performance with high piezoelectric constant (d 33 = 167 pC/N), high planar electromechanical coupling factor (k p = 0.30), high mechanical quality factor (Q m = 118), high relative dielectric constant (e r = 1470) and lower dissipation factor (tand = 0.056) at a frequency of 10 kHz.