| BaTiO3based materials have been extensively studied due to their fascinating ferroelectric and piezoelectric properties. No matter ceramics or thin films, they are widely used in commercial electronic industry. This thesis focused on preparation of BaZr0.25Ti0.75O3(BZT) ceramics and BaTiO3nanotube arrays, which contents two sections of experiments:Section one is experiment about low temperature sintering of Li2O and B2O3doped BaZr0.25Ti0.75O3ceramics, and the investigation of two-step sintering method used in synthesis of BZT. These ceramics were prepared by conventional ceramic process at a relatively low sintering temperature and with an addition of Li2O and B2O3as the liquid-phase sintering aids. When the contents of Li2O and B2O3reached1wt%and0.5wt%respectively, sintering aids preformed high efficiency and all BZT samples presented perovskite structure. There are two effects work on the lattice constant. For one thing, the Li+or B3+may occupy the site of Ba2+which caused the XRD patterns shifted to the higher2-theta. For another, oxides existed at the grain boundaries as amorphous glass phase would arouse stress which acts on the grains inducing the lattice constant increased. The dielectric properties deteriorated with the adding of oxides, however, on the premise of application, the sintering temperature can be reduced of200-300℃from the1450℃. According to the investigation of results, the dielectric properties of sample which was sintered at1200℃with only0.5wt%B2O3doped had the close dielectric properties of the sample sintered at1450℃. It shows that if the modified method was adopted, the dielectric properties can reach a perfect state.Moreover, the sintering temperature can reduce of200℃at least when two-step method was used. The dielectric constant of two-step sintered sample can reach8035, which was higher than the sample sintered at1450℃with a conventional route. The new method avoids the high temperature and abnormal growth of grains which may worsen the dielectric properties and shows bright application prospects.Section two is the experiment about well-ordered arrays of ferroelectric BaTiO3nanostructures which were prepared from titania nanotube arrays (TiNTs) by hydrothermal method. The TiNTs were prepared in a certain parameter of anodic oxidation with the length of them was2μm and inner diameter of them was around50nm. And the tube morphology of the sample arranged well which showed an amorphous structure. After2h hydrothermal reaction with the temperature of200℃, the BaTiO3nanostructures with perfect crystalline were prepared. According to the SEM images, the as-prepared sample with inner diameter of them was around30-40nm which was covered by an anamorphotic BaTiO3layer. The main reason may be the time or temperature of the hydrothermal reaction is not perfect, and the overreaction led to distortion of nano-tubes. TEM images combined with SAED pattern were used to illustrate the single-crystalline BaTiO3nanostructures with ferroelectric domains spread all over the nanotubes. What’s more, ferroelectric nature was confirmed by P-E hysteresis loops with remanent polarization and coercive field were respective8.93μC/cm2and53kV/cm when the voltage of applied electric field was25V. Perovskite structure was proved by the measurement of XPS wide-band spectrum, however, binding energy of Ti2p3/2and Ti2p1/2shifted to lower energy side in Ti spectrum, which concentrated that a shift from Ti4+to Ti3+. Further more, the area integrals from fitted curves of O spectrum proved the existing of hydroxyl groups or absorbed oxygen on the surface. |
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