In the present study, the HA-TiO2 nanostructured composite coatings with 0, 10 and 20 wt% TiO2 were fabricated by electrophoretic deposition at 20 V for 3 min. Electrochemical corrosion behavior of the samples was conducted in SBF solution at 37oC by potentiodynamic pol More
In the present study, the HA-TiO2 nanostructured composite coatings with 0, 10 and 20 wt% TiO2 were fabricated by electrophoretic deposition at 20 V for 3 min. Electrochemical corrosion behavior of the samples was conducted in SBF solution at 37oC by potentiodynamic polarization tests. For the effect of titania on apatite formation, electrochemical impedance spectroscopy after in-vitro tests were conducted on coatings. The variation of electrochemical parameters in equivalent circuit with different times of apatite formation was discussed for each sample. The lowest corrosion current density (icorr) and the highest corrosion potential (Ecorr) and linear polarization resistance (Rp) were obtained for HA-20 wt% TiO2 sample. The EIS analysis revealed that the total resistance of HA-20 wt% TiO2 sample is higher than that of other samples. The ICP analysis of Ca2+ concentration of SBF solution showed that the highest dissolution rate was achieved for HA sample. The concentration of Ca2+ of HA-20 wt% TiO2 sample remained almost constant after 15 days immersion which indicated the accelerated apatite formation. Moreover, the bonding strength of coating was increased by a factor of 2 with the addition of titania in HA-20 wt% TiO2 sample.
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In this research study, the coating of titania particles on the SrFe12O19/SiO2 composite was successfully accomplished by the sol-gel process. For this purpose, first, the strontium hexaferrite particles were prepared by co-precipitation route with Fe3+/Sr2+ molar ratio More
In this research study, the coating of titania particles on the SrFe12O19/SiO2 composite was successfully accomplished by the sol-gel process. For this purpose, first, the strontium hexaferrite particles were prepared by co-precipitation route with Fe3+/Sr2+ molar ratios of 11 and 12 and subsequent calcination treatment. The formation of single phase strontium hexaferrite particles, as hard magnetic cores of the composite, was attained in the molar ratio of Fe3+/Sr2+=12 after calcination at 950 °C. In the next step, the silica coating of hexaferrite particles was performed using the tetraethyl orthosilicate (TEOS) precursor via the Stöber method. In the end, the covering of titania particles on the SrFe12O19/SiO2 composite was carried out by utilizing titanium n-butoxide (TNBT) precursor. The as-prepared composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and vibrating sample magnetometry (VSM) analyses. The results confirmed the core/shell/shell structure of the synthesized SrFe12O19/SiO2/TiO2 composite. The analysis of the magnetic properties showed that saturation magnetization (Ms) of strontium hexaferrite powder was obtained as 58 emu/g. After the successive coating of SiO2 and TiO2 shells, this amount has reached to 56 emu/g and 37 emu/g, respectively.
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In this study, Fe3O4 / SiO2 / TiO2 composite was prepared with core-shell-shell structure using a wet chemical method. At first the composite Fe3O4 / SiO2 was synthesized via Tetraethyl orthosilicate (TEOS) precursor. Then a shell of TiO2 was coated directly on it. Fe3O More
In this study, Fe3O4 / SiO2 / TiO2 composite was prepared with core-shell-shell structure using a wet chemical method. At first the composite Fe3O4 / SiO2 was synthesized via Tetraethyl orthosilicate (TEOS) precursor. Then a shell of TiO2 was coated directly on it. Fe3O4 / SiO2 / TiO2 microstructures produced were characterized by environmental scanning electron microscopy analysis (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy devices (FTIR). The results showed that SiO2 and TiO2 layers has been coating successfully. The results indicated that the mean size of Fe3O4 particles was about 300-400 nm and thickness of the TiO2 and SiO2 shells was about 4 and 30 nm, respectively. magnetic properties of the synthesized composite were studied by Vibrating Sample Magnetometer (VSM). Pure Fe3O4 and Fe3O4@SiO2@TiO2 composites magnetization saturation (Ms) obtained 80 and 37 emu/g, respectively. also the remanent magnetization (Mr) value of Fe3O4 and Fe3O4 / SiO2 / TiO2 microstructures was 8 and 6.43 emu/g, respectively.
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Dispersion of nanotitan particles in polyurethane (PU) resin plays an important role to achievement better mechanical and physical properties. In this study nanocomposite coating was performed by incorporating nanotitania pigment with rutile and anatase phase in polyure More
Dispersion of nanotitan particles in polyurethane (PU) resin plays an important role to achievement better mechanical and physical properties. In this study nanocomposite coating was performed by incorporating nanotitania pigment with rutile and anatase phase in polyurethane to different loading level (0.1, 0.5, 1.0 and 2.0% by weight). Dispersion of nanoparticles in PU matrix was done by using ultrasonication mixing machine (2 h) and rotary mixer (3 h) and also again UT mixing machine (1 h) and finally gas removing. After addition of the appropriate amount of hardener, prepared nanocomposite coating was investigated by applying on steel and glass substrate and after 2weeks time for curing, exposing them to UV weathering, salt spray, scratch and hardness testing. The dispersion quality and surface morphology of nanocomposite coating was evaluated by using different analytical techniques. Dispersion quality of nanocomposite was investigated using optical microscopy. Dry film thickness (DFT) of samples was mostly in the range 90 µm. Roughness after exposing of naoncomposites on UV radiation and salt spray measurement by atomic force microscopy (AFM) topography and analysis by this apparatus and mechanical behavior also by using hardness and scratch test and also by colorimetry measurements, surface degradation of PU nanocomposite coatings was characterized by color changing, defined as the color measurement, after being exposed to accelerated weathering conditions.
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