Improvement the dielectric and impedance properties of Pb-free Bi0.5Na0.5TiO3-SrTiO3 piezoelectric materials modified by Fe2O3

Abstract

The focus of this study is on the Fe2O3-doped Bi0.5Na0.5TiO3-SrTiO3 piezoelectric material. This is important to find ecologically acceptable piezoelectric materials. This research aims to obtain a lead-free piezoelectric material because lead is a material that is not environmentally friendly. An alternative solution is a piezoelectric material based on BNT-ST, which in this case is doped with Fe2O3 material. The study of Fe2O3 doped Bi0.5Na0.5TiO3-SrTiO3 piezoelectric material prepared by the solid-state reaction method was carried out to determine the optimum composition of the material formed. Doping variations are 0; 2.5; 5; 7.5; and 10 in mol %. The examinations were performed using X-ray diffraction (XRD) spectroscopy, a Scanning Electron Microscope (SEM), and an LCR meter. The Fe2O3 doped Bi0.5Na0.5TiO3-SrTiO3 produced a new compound in the form of FeBi5Ti3O15-Na2Ti3O7-SrTiO3 with the crystal structure of cubic, orthorhombic, and monoclinic, as well as the increasing crystalline size with the addition of dopants, exclude at 5 mol % and 7.5 mol %. FeBi5Ti3O15-Na2Ti3O7-SrTiO3 also produces varying particle sizes, which are between 0.88–8.23 µm. From the obtained data, the optimum composition of Fe2O3 doped Bi0.5Na0.5TiO3-SrTiO3 was the 2.5 mol % of Fe2O3 due to it having the highest dielectric constant (er ) and temperature Curie (Tc ), and also the lowest material impedance (Z) with the er of 12.037 at Tc of 400 °C and Z of 135 kΩ. The high piezoelectricity, which is indicated by the high value of the dielectric constant and Curie temperature, is possible due to the presence of a greater number of sodium ions in the Na2Ti3O7 phase. Sodium ions are ions with good electrical storage capabilities. The increase in dielectric constant in the BNT-ST piezoelectric obtained by the addition of Fe2O3 shows that this material can be used as a substitute for lead-based piezoelectric materials so that it is secure for the environment. The piezoelectric material of BNT-ST doped with Fe2O3 earned from this research can be applied to obtain electricity with a optimal value when given mechanical pressure