The Influence Of Doping Vario-property On The Microstructure And Piezoelectric Properties Of BCZT-base Lead-free Piezoelectric Ceramics

Piezoelectric ceramics occupy an important position in the material field, which due to the special properties of mechanical-electrical energy conversion. BCZT lead-free piezoelectric ceramics is expected to replace Pb-base ceramics, due to the excel ent piezoelectric properties. However the high sintering temperature and low Curie temperature of BCZT ceramics still has not been a great deal of improvement. The BCZT-base lead-free piezoceramics were prepared by conventional solid-state sintering method. The effects of sintering temperature, La2O3, Sn O2, Sm2O3 dopant on phase structure, microstructure and electrical properties of BCZT-base ceramics were investigated. Furthermore, the ferroelectric properties of Sn O2, Sm2O3 dopant on BCZT-base ceramics were studied. Above al, some main conclusions are as follow:1. The effect of sintering temperature on phase structure, microstructure and electrical properties of 0.996 Ba0.85Ca0.15Zr0.1Ti0.9O3-0.004 Bi YO3 piezoceramics were investigated. The results indicate that the BCZT-BY ceramic samples have dense microstructure when sintered at 1420 o C, its electric properties are as follow: d33 = 130 p C/N, kp = 18.2 %, εr = 4225, tan δ = 1.95%.2. The effect of La2O3-doping on phase structure, microstructure and electrical properties of Ba0.85Ca0.15Zr0.1Ti0.9O3-0.8 wt. % Si O2 piezoceramics were investigated. The results show that the BCZT-Si-x La samples have dense microstructure with large grains, distribution well and little porosity when x = 0.4 wt. %, and the as obtain the excel ent properties piezoceramics showed; d33 = 153 p C/N, εr = 4487, tan δ = 2.44 %.3. The effect of Sn O2-doping on phase structure, electrical properties and the dielectric relaxation behavior of Ba0.85Ca0.15Zr0.1Ti0.9O3-0.2wt. % Cu O2 piezoceramics were investigated. It obtained the superior properties of BCZT-Cu-x Sn piezoceramics when the content of Sn O2 is 0.3 wt.%; d33 = 286 p C/N, kp = 36.01%, εr = 3118, tan δ = 1.64%. The results of dielectric properties` investigation indicate that, the Cuire Temperature of BCZTCu-x Sn piezoceramics were reduced from 86.1o C to 67.4o C. Besides, the dispersion coefficient γ = 1.841 after doped Sn O2, which show the typical diffuse phase transition and dielectric relaxor.4. The effect of Sm2O3-doping on microstructure, electrical properties, diffuse phase transition and dielectric relaxor of(Ba0.85Ca0.15)(Zr0.1Ti0.893Mn0.005Y0.002)O3 piezoceramics were investigated. The results show that the BCZTMY- x Sm samples have the excel ent properties when x = 0.3 wt.%; d33 = 171 p C/N, kp = 20.45%, εr = 5451, tan δ = 2.03%. Besides, the results of dielectric properties` investigation indicate that the Tc were reduced after doped Sm2O3. Moreover, the Sm2O3-doped BCZTMY piezoceramics appear the polarized microdistrict, which due to the specific elements doping break the ions arranged of the BCZT crystal lattice in a small area. Thus showing the typical diffuse phase transition and dielectric relaxor.