BT-BKT无铅压电陶瓷的性能研究

Dielectric and piezoelectric properties of BT-BKT lead-free piezoceramics

通过在BaTiO3(BT)中加入不同含量的Bi0.5K0.5TiO3(BKT),研究了(1–x)BT-xBKT系无铅压电陶瓷的性能特征。经1200℃空气气氛2～4h烧结的陶瓷形成了钙钛矿结构固溶体单一相。陶瓷的介电、压电、铁电性质受BKT含量的影响显著。随着BKT的加入,陶瓷表现出一定的弛豫型铁电体特征。当x为0.20时,陶瓷具有较小的tanδ,并且介电性能稳定。tC及EC随BKT添加量的增加而增大。当x为0.20时,陶瓷的tC达182℃,d33达到63pC/N;x为0.10时,Pr达最大值9.4×10–6C/cm2。

Lead-free （1-x）BaTiO3-xBi0.5K0.5TiO3 （x=0.09, 0.1, 0.11, 0.12, 0.13, 0.15, 0.18, 0.25, 0.30） piezoelectric ceramics were fabricated by sintering at 1 200 ℃ for 2-4 h in air atmosphere. The crystal structure was investigated by X-ray diffraction. The dielectric, ferroelectric and piezoelectric properties were also studied. The ceramics with different content of BKT formed single-phase solid solutions with perovskite structure. As the addition of BKT, the ceramics show a relaxor behavior. When x =0.2, the ceramic has stable permittivity and low dielectric losses. The piezoelectric constant d33 of the ceramic is 63 pC/N. The highest Curie temperature, about 182 ℃, is obtained when x=-0.20. The largest value of remnant polarization, Pr=9.4 ×10^-6 C/cm^2, is obtained when x= 0.10, whereas the coercive field, increased monotonously as the B KT content increased.