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Due to magnesium's active chemical property, a novel environmental protective water based metallic coating was developed, which mainly contains metal flake, nano-silica, silicate and silane. The coating's properties were investigated by neutral salt spray test, micro-hardness testing, adhesion test and electrochemical technique etc. Meanwhile the coating surface and microstructure was observed by scanning electron microscopy (SEM). Furthermore, the effect of nano silica on the coating was also explored. Results showed that an excellent adhesive, heat-resisting, protective coating for AZ91D magnesium alloy could be achieved by this technique. It also indicated that nano silica could greatly improve the properties of coating. In the paper, mechanism of nano silica coating was also discussed.

Magnesium (Mg) alloys have been increasingly used in industries and biomaterial fields due to low density, high specific strength and biodegradability. However, poor surface-related properties are major factors that limit their practical applications. This paper mainly focuses on laser-based anti-corrosion technologies for Mg alloys, beginning with a brief review of conventional methods, and then demonstrates the feasibility of laser surface technologies including laser surface melting (LSM), laser surface alloying (LSA), laser surface cladding (LSC) and laser shock peening (LSP) in achieving enhancement of corrosion resistance. The mechanism and capability of each technique in corrosion resistance is carefully discussed. Finally, an outlook of the development of laser surface technology for Mg alloy is further concluded, aiming to serve as a guide for further research both in industry applications and biomedical devices.

In the present study, a scalable-manufactured and environmental-friendly method was proposed to fabricate the superhydrophobic coating on titanium alloy. The hierarchical binary surface structures were obtained by hydrothermal treatment of titanium alloy with oxalic acid and sodium hydroxide solutions successively. The hierarchical structure surfaces after fluoroalkyl-silane modification possessed a maximum contact angle of 158.7^∘ and a sliding angle of 4.3^∘. The low contact angle hysteresis surface can lead to efficient self-cleaning performance, which was confirmed by the bounce and roll off of water droplet on the surface. Furthermore, the anticorrosion behaviors of the superhydrophobic coating in 3.5wt.% NaCl solution was evaluated by the electrochemical impedance spectroscopy (EIS). It was found that the superhydrophobic coating can maintain its superhydrophobic state (150^∘) within 48 h, thereby effectively preventing the corrosive medium from penetrating into the coating. This simple yet fast anti-corrosion/self-cleaning superhydrophobic coating manufacturing strategy will enlighten its potential application in the engineering fields.

The fabrication of hydrophobic coatings whose water contact angle is over 90^∘ has high potential to induce waterproof, anti-fouling, and self-cleaning properties. In this research, a composite hydrophobic coating was constructed with flower-shaped ZnO, waterborne acrylic resin that is harmless to the environment and stearic acid. The hydrophobicity of the coating is tested by means of water contact angle method (WCA). The WCA of the composite coating can be extended up to 128^∘. The composite hydrophobic coating displayed good performances of anti-corrosion and self-cleaning. In addition, the composite hydrophobic coatings also showed good photo-catalytic degradation property under visible light irradiation, which was shown by means of the methylene blue test. The composite coating soaked in 3.5wt.% NaCl solution had excellent durability. It is proved that such produced hydrophobic coatings can be widely applied to the field of anti-corrosion and self-cleaning.

The composite conductive copolymers of polyaniline/polythiophene (Pani/PTH) were successfully prepared by an electrochemical method on a stainless steel surface containing both aniline and thiophene in a 0.3mol/L oxalic acid solution. The anti-corrosion performance of the Pani/PTH on stainless steel surfaces was investigated in acidic media by polarization curve analysis and electrochemical impedance spectroscopy (EIS). Additionally, the surface morphology of Pani/PTH composite conductive copolymers was observed by scanning electron microscopy (SEM). The results showed that the Pani/PTH copolymers strongly adhered to the surface of the stainless steel. Compared with that of bare stainless steel, composite conductive copolymers of Pani/PTH on the stainless steel surface provided good anti-corrosion behavior; additionally, the corrosion potential could be improved by approximately 400mV, while the current density decreased by two orders of magnitude in the corrosion media. The above results were in accordance with the SEM characterization results. The SEM spectrum showed that the Pani/PTH film had a uniform, dense and shiny structure, so it had better anti-corrosion behavior.

The zinc phosphate nanocrystals were synthesized by the ultrasonic–hydrothermal synergistic route. The ultrasonic–hydrothermal synergistic route can not only decrease the size of the zinc phosphate material, but also improve the crystallinity of the product. The transmission electron microscopy (TEM) image showed that the needle-like zinc phosphate product was 200–300 nm in length and 70–80 nm in width. The anti-corrosion tests revealed that the salt atmosphere-resistant time about 1056 h was longer than 768 h common zinc phosphate materials in the market. The mechanisms of ultrasonic–hydrothermal synergistic route and anti-corrosion were discussed.

The superhydrophobic surfaces on kovar alloys substrates were prepared by a two-step methodology. The Kovar alloys sheets were first immersed in the HNO₃(10%) and H₂O₂(10%) mixed solution for 10min, and then immersed in the 0.01mol/L ethanol solution of stearic acid for 48h. The sample surfaces were characterized by SEM, CLSM, EDS,XPS and optical contact angle meter. The results show that the surfaces composed of porous structures and were successfully modified with stearic acid, the contact angle of the prepared surfaces were as large as 154◦. The anti-corrosion property was evaluated by Tafel plot, as the superhydrophobic surfaces could prevent the contact of metal with Cl- ion, the surfaces had a good anti-corrosion property.