The 0.6(Bi0.85La0.15)FeO3-0.4PbTiO3 (BLF-PT) ceramics were prepared by tape casting method. Effects of binder (polyvinylbutyl dibutyl PVB), plasticizer (phthalate-polyethylene glycol DBP-PEG) and dispersant (triethylolamine, TEA) concentration on the rheological properties of BLF-PT slurry were investigated. The optimized component ratio for ceramics powders, binder, plasticizer, dispersant and solvent (ethanol, EtOH) in the slurry was 50 wt.%, 4 wt.%, 6 wt.%, 1 wt.% and 39 wt.%. The dielectric constant εr, loss tanδ, and remnant polarization Pr of BLF-PT ceramics laminated from the tapes were 525 (1 kHz), 1.7% (1 kHz) and 30 μC/cm2 (45 kV/cm), respectively, which were comparable to those of BLF-PT ceramics prepared by traditional solid state reaction method.

(1-x)(Bi0.8Gd0.2)FeO3-xPbTiO3 (BGF-PT) solid solutions ceramics of x=0.55,0.50,0.4975, 0.49 and 0.45 were prepared by the mixed oxide method. Gd3+ of 20 at% was introduced into the Bi3+ site to improve the dielectric and piezoelectric properties of BFPT without causing the significant reduction of Curie temperature (Tc). X-ray diffraction analysis shows a transformation from the tetragonal (T) to rhombohedral (R) phase with the increase of BGF content. The morphotropic phase boundary was determined by measuring the dielectric and piezoelectric properties of BGF-PT within a wide composition range. BGF-PT for x=0.4975 shows the coexistence of T and R phases with the dielectric constant and loss of about 895 and 0.031 respectively at the frequency of 102 Hz.

Pb(Zr0.53Ti0.47)O3 (PZT) films have been fabricated on stainless steel substrates by a Polyvinylpirrolidone (PVP) modified sol-gel route. The single layer of about 0.26 μm was achieved by using the PVP-modified PZT sol, and Crack-free PZT films with thickness of up to 2.37 μm were fabricated by repeating the deposition process. The variations in crystallite orientation, microstructure, dielectric and ferroelectric properties of PZT films were investigated as a function of film thickness. Our results indicate that PZT films prepared on stainless steel substrates maintain good dielectric and ferroelectric properties.

Polycrystalline solutions of 0.6(Bi0.9La0.1)FeO3-0.4Pb(Ti1-xMnx)O3(BLF-PTM, x=0 and 0.01)have been fabricated by the so-gel process combined with a solid state reaction method. BLF-PTM exhibits the nonlinear dielectric and piezoelectric responses under applied fields. Rayleigh law has been used to evaluate the irreversible contribution of the domain walls movement to the nonlinear dielectric response. Rayleigh analysis reveals that a mechanism with no associated loss exists in the BLF-PTM of x=0.01. The real part piezoelectric coefficient of BLF-PTM linearly increases with increasing the electric fields. The dielectric and piezoelectric nonlinear coefficient of 0.17×10-3 m/V and 0.897 ×10-17 m2/V2 respectively are obtained for BLF-PTM of x=0.01,which are smaller than those of 0.22×10-3 m/V and 1.19 ×10-17 m2/V2 for BLF-PTM of x=0. Our results indicate that Mn doping increase the intrinsic piezoelectric properties of BLF-PTM reducing the extrinsic contributions to piezoelectric responses.

Ferroelectric 0.7BiFeO3-0.3PbTiO3 (BFO-PT) films were deposited on stainless steel substrates by the sol-gel method. A thin layer of PbTiO3 (PT) was introduced between the substrates and BFO-PT films in order to decrease the annealing temperature of BFO-PT films. X-ray diffraction analysis reveals that BFO-PT films could be well crystallized into the perovskite structure at about 575 oC. Scanning electron microscope (SEM) images show that BFO-PT thin films have grain size of about 50∼60 nm. Our results indicated BFO-PT films deposited on stainless steel substrates maintained the excellent ferroelectric properties with remnant polarization of about 40∼50 μC/cm2.

A facile hydrothermal route assisted by polyethylene glycol (PEG) 400 was utilized to synthesize single-phase Bi2Fe4O9 crystallites. X-ray diffraction results showed the products with PEG 400 of 30 g/L exhibited a preferred growth along the (001) plane. Transmission electron microscopy indicated that the morphology of the as-prepared Bi2Fe4O9 crystallites with PEG 400 were plake-like and rod-like. Strong absorption in visible-light region of the products was characterized by UV-vis diffuse reflectance spectrum (UV-DRS). The photocatalytic activity of Bi2Fe4O9 crystallites was evaluated on degradation of methyl orange (MO) under visible light irradiation. For 3 h irradiation, the degradation ratio was increased to 93% with the aid of a small amount of H2O2. The analysis of FT-IR spectra proved that the Bi2Fe4O9 catalysts were remained stable after the photocalytic reactions.

Sillenite Bi25FeO40 crystallites have been fabricated via a sol-gel approach. X-ray diffraction results show that single-phase Bi25FeO40 can be synthesized at the annealing temperature of 600 oC with the help of PEG additive. The amount of additives and the annealing temperature has great effects on the formation of phase pure Bi25FeO40 crystallites. The morphologies of Bi25FeO40 crystallites were observed by SEM techniques. UV-vis diffuse reflectance spectroscopy indicated the good visible light absorption of Bi25FeO40 crystallites. The photo-catalytic activity of Bi25FeO40 powders was evaluated by the degradation of methyl orange solution assisted by H2O2 under UV-Vis light and Vis-only light irradiation, which suggested that Bi25FeO40 crystallites are potential photocatalytic materials.