Papers by Author: Hui Wang

Abstract: Combined with sol-gel method, ultrasonic impregnation approach was employed to prepare TiO2/ Al2O3 surface composite on aluminum. The results showed that with the effect of ultrasonic, the TiO2 colloid fabricated by sol-gel method can enter the inner of the ordered AAO film to form anatase TiO2 nano wires after being heated at 500°C for 2h. The diameters and lengths of TiO2 nano wires were controlled by the diameter and thickness of AAO film. Close to the bottom of aluminum substrate, the TiO2 nano wires became nano pipes, plates and particles.

Abstract: Polymeric compounds are of great interest as corrosion inhibitors in acidic environment due to their inherent stability. Polymeric film is effectively used for the protection of metals partly owing to their capacity to act as a physical barrier between the metal surface and the corrosive environment. In this paper, a cation polyelectrolyte inhibitor (Quaternary Polyethyleneimine, QPEI) was prepared. The quality and inhibition efficiency of QPEI self-adsorbed films were studied by polarization curve and electrochemical impedance spectroscopy, respectively. The compositions and morphologies of the polymer film on the steel surface were examined with the aids of SEM and XPS, respectively. The results showed that QPEI could greatly retard the corrosion of iron in sulfuric acid, which was attributed mainly to the protective QPEI film formed on the surface. Meanwhile, the inhibition of QPEI could be supposed as a mixed process, in which both cathodic and anodic corrosions were simultaneously restrained. Based on the results of XPS and SEM, it could be evidenced that the QPEI can form a protective polymer layer on the metal surface by adsorption.

Abstract: Anodic alumina oxide (AAO) templates with multi-branched structure were fabricated in a phosphoric acid. Atomic force microscope (AFM) was utilized to investigate the unstable growth of porous oxide film in initial stage. The morphologies of cross-section of AAO templates at different current density were also studied with FESEM. The results show that the acquired AAO templates are of multi-branched structure with large size. The diameter of pores on outer surface ranges from 150 to 220 nm, and the width of branches from 100-120 nm. This structure can be due to the unstable growth of AAO film in initial stage. Besides, the structure of AAO template is sensitive to the current density and the order degree decreases with the increase of current density: at 1.0A/dm2, most of tubes are not straight and some divided into two branches; at 2.0A/dm2, all tubes grow disorderly and form net-like structure. In this electrolyte, different types of structure of AAO templates can be acquired by adjusting current density, which may be used for the synthesis of new types of nanowires with improved mechanical properties.