سال انتشار: ۱۳۸۷
محل انتشار: دومین کنگره بین المللی علوم و فناوری نانو
تعداد صفحات: ۲
M Haj-Fathalian – Departmant of Materials Science and Engineering, Sharif University of Technology,Sharif, Tehran
H. R. madaah hosseini –
Z. A. Nemati –
Recently, there has been continued growth of interest in the use of BaTiO3-based ceramics, because they are promising materials for tunable microwave device application such as electronically tunable mixer, filters, capacitors, resonators and phase shiftersBaTiO3-based solid solutions exhibit high piezoelectric and ferroelectric properties. One of the most favorable systems of these materials is Ba(Ti1-xZrx)O3 and their nanostructured specimens have a great potential for applications such as capacitors, MLCCs, actuators, transducers and dielectrics due to their high K values.Ba(Ti1-xZrx)O3 (BZT) ceramics are obtained by substituting ions at the B site of BaTiO3 with Zr ions. It is reported that BZT system has high dielectric constant and low loss tangent at room temperature. The ferroelectric properties of BZT are largely dependent on the amount of Zr substitution [2, 3]. The dielectric data of Ba(Ti1-xZrx)O3 ceramics suggest a normal ferroelectric behavior for compositions 0≤x≤۰٫۱ and relaxor character for 0.1≤x≤۰٫۴۲ when degree of diffuseness of the ferro-para phase transition is increasing with x  and antiferroelectric properties for Zr-rich compositions. The relaxor state is characterized by a strong frequency dependence of the permittivity below the maximum permittivity temperature Tm, a shift of Tm towards higher values with increasing frequency and deviations from the Curie-Weiss law in the paraelectric phase . Therefore, these compositional limits are very sensitive to the preparation method, the presence of possible secondary phases and the microstructural characteristics.In the present study nano crystalline Ba(Ti1-xZrx)O3(x=0.1-0.4) which is called BZT composite has been prepared by mechanical alloying and/or solid state reaction. The parameters affecting the process and properties were evaluated. For the composition x=0.4 that prepared by high energy miling(Expex), samples with nano structure sized were obtioned.