| The Barium Titanate electronic ceramic is a new kind of lead-free piezoelectric ceramic material, which are widely used in light, sound, electronics and other fields. As one of the most important kinds of ceramic materials, Barium Titanate is the base raw material of electronic ceramic components, and known as the backbone of electronic ceramics. Since1942, Wainer, et.al. found that Barium Titanate has good dielectric and piezoelectric properties, this kind of ferroelectric ceramic has acquired great attention and developed rapidly in recent decades. However, the Curie temperature of Barium Titanate is around120℃, restricting its application at room temperature.The BZT-BCT ceramic, as a new kind of binary-system ceramic material, showed very high piezoelectric properties around morphotropic phase boundary (MPB), the value of d33can reach at about600pC/N, which can be comparable with the piezoelectric properties of lead-based ceramic materials. However, a series of disappointing faults still exist in the BCT-BZT system and limit its broader application.(Ba0.85Ca0.15)(Zr0.1Ti0.9) O3(hereinafter referred to as BCZT) lead-free piezoelectric ceramics with high electrical properties were successfully prepared by traditional solid phase reaction in this paper. Based on the shortcomings of high sintering temperatures and poor temperature stability, this new ceramic systems were designed and studied by doping and modification to reduce the sintering temperature and improve temperature stability of the BCZT ceramic, aiming to provide candidate materials and references for obtaining excellent lead-free piezoelectric ceramics. The main results are as follows:1、The ceramic systems of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3-BiCoO3(BCZT-BCO)、(Ba0.85Ca0.15)(Zr0.1Ti0.9)O3-BiMnO3(BCZT-BMO) and (Ba0.85Ca0.15)(Zr0.1Ti0.9)o3-BiAIO3(BCZT-BAO) were designed and prepared by traditional solid phase method, respectively. Effect of the composition on the sintering temperature, phase structure, microstructure, dielectric properties, piezoelectric, ferroelectric properties and strain of the BCZT ceramics were studied in detail. The results are shown as that:(1) It was found that the sintering temperature is reduced from1450℃to1380℃and showed better properties, when the content of BiCoo3is0.006. Meanwhile the good temperature stability are obtained around the temperature range of-60℃to80℃: △C/C25oC=2.49～0.52. The best properties are as follows:p=5.26g/cm3,d33=420pC/N, kp=0.45,Qm=144, S=0.639, Pr=8.982μc/cm2,εr=2908, tanδ=0.008, Tc=79℃.(2) It was found that the sintering temperature is reduced from1450℃to1380℃and showed better properties, when the content of BiMno3is0.003. Meanwhile the good temperature stability are obtained around the temperature range of-60℃to80℃: A C/C25oC=2.49～0.52. The best properties are as follows:p=5.46g/cm3, d33=415pC/N, kp=0.46,Qm=134,s=0.513, Pr=8.982μC/cm2,εr=3358, tanδ=0.019,Tc=94℃,△C/C25℃=-0.84～0.66.(3) It was found that the sintering temperature is reduced from1450℃to1300℃and showed better properties, when the content of BiAlO3is0.008. Meanwhile the good temperature stability are obtained around the temperature range of-60℃to80℃:△C/C25oC=2.49～0.52. The best properties are as follows:p=5.57g/cm3,d33=442pC/N, kp=0.42, S=0.699, PT=9.38μc/cm2, εr=3217, tanδ=0.021, Tc=72℃,△C/C25℃=-0.78～0.7。2、The effect of BiMO3(M=Co, Mn, Al) on the properties of BCZT ceramic systems were studied in detail. A ferroelectric phase transition behavior from T phase to R phase is shown in the ceramics and great properties are obtained from the results. The similar MPB area appears when the phase transition behavior occurs at room temperature. The reasons of high performance and internal mechanism which affect the properties of BCZT ceramic are mainly analyzed and discussed from the inside structure of introducing ions. Providing a theoretical guidance for designing good alternative piezoelectric material with low sintering temperature, high piezoelectric properties and good temperature stability for practical application in electronic components. |
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