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Anodic Oxide Films (anodic + oxide_film)
Selected AbstractsAnodic oxide films on silicon carbideCRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2007S. K. Lilov Abstract Anodic oxide films were grown on SiC using various electrolytes. The obtained oxide films were compared and some of their electrophysical properties were investigated. Anodic oxidation of SiC was shown to be useful for precise removal of layers as well as for identification of the polar faces of SiC crystals. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Evaluation of different sealing methods for anodized aluminum-silicon carbide (Al/SiC) composites using EIS and SEM techniquesMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 11 2007H. Herrera-Hernandez Electrochemical impedance spectroscopy (EIS) and the scanning electron microscope (SEM) have been used in an investigation of the effectiveness of various sealing methods that can be used to improve the corrosion resistance of an anodized aluminum-silicon carbide (Al/SiC) composite. Anodic oxide films were grown on Al7075-T6 and the Al/SiC composite by sulfuric acid anodizing and sealing in a cold saturated solution of nickel acetate. Other samples were sealed using the traditional method of boiling water or hot nickel acetate for comparison. The results revealed a uniform anodized layer on Al7075-T6 that resisted pitting corrosion for more than 2,weeks exposure to NaCl, whereas a cracked oxide film with variations in thickness was observed on the composite material. Pit initiation occurred in less than 5,days on the anodized Al/SiC that was sealed in the hot solutions. This study suggests that the traditional hot sealing methods did not provide sufficient corrosion protection for aluminum metal,matrix composites (MMCs) because the reinforcing SiC particles deteriorated the surface film structure. However, this defective film can be repaired by nickel hydrate precipitation during cold sealing or by applying a thick polyurethane coating. [source] Preparation and Electrical Properties of an Anodized Al2O3,BaTiO3 Composite FilmJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2008Xianfeng Du A highly stable, water-based barium titanate BaTiO3, BT, sol was synthesized using a sol,gel route through a chelate lactate technique. Dried BT precursor powders were measured by thermal gravimetry,differential thermal analysis and X-ray diffraction. It was found that BT powders first converted into barium carbonate BaCO3, Ti complex, and intermediate phase Ba2Ti2O5CO3, and then transformed into perovskite phase BaTiO3. The crystallization temperature was about 550°C. The low-voltage etched aluminum foils were covered with BT sol by dip coating, and then annealed at 600°C for 30 min in air. After that, the samples were anodized in a 15 wt% aqueous solution of ammonium adipate. The voltage,time variations during anodizing were monitored, and the electrical properties of the anodic oxide film were examined. It was shown that the specific capacitance, the product of specific capacitance and withstanding voltage, and leakage current of samples with a BT coating were about 48.93%, 38.50%, and 167% larger than that without a BT coating, respectively. [source] | ||||||||||