In this review, the major anti-fouling strategies based on physical-, chemical- and biological-methods are presented, while their advantages and disadvantages are analyzed. Then fouling release-, conductive antifouling- and silicate antifouling-coatings are described in detail. It is proposed that the fouling release coatings which combine the nanotechnology with the bionic technology will be one of the most important antifouling approaches.

Polyaniline (Pani) film was applied onto AZ91 magnesium alloy in aqueous solutions containing oxalic acid and aniline monomer by cyclic voltammetry (CV) technique, which then was characterized by means of IR and SEM technique. Furthermore, the corrosion performance of the coating was evaluated in 3.5%NaCl solution through examining the polarization curves, open circuit potential versus time and the electrochemical impedance spectroscopy (EIS). The results indicated that the Pani coating could effectively shift the free corrosion potential much positively for the coated AZ91 magnesium and led to significantly diminish its corrosion current density by two orders of magnitude. Long-term immersion experiments indicated that the Pani coating can effectively hinder the permeation of corrosive species toward matrix, thereby prevent AZ91 magnesium alloy from corrosion.

A micro-arc oxidation coating containing uniformly distributed fine pores was obtained on AZ31B Mg alloy in a glycerol containing silicate aqueous solution. The effect of electrical parameters, such as voltage, frequency and duty cycle on the micromorphology, corrosion resistance and thickness of the micro-arc oxidation (MAO) coating was investigated by means of scanning electron microscope (SEM), electrochemical workstation and thickness gauge. The results show that the size of micro-pores and the thickness of MAO coating increase accordingly with the increasing voltage, while the corrosion resistance first increases and then decreases. However, the diameter of micros-pores decreases with the increasing frequency while corrosion resistance increases; the frequency has a weak effect on the thickness of the coating; when the duty cycle is larger than 45%, the size of micro-pores and thickness are apt to increase while the corrosion resistance decreases due to the breakdown and damage of MAO coating. The optimal electrical parameters for obtaining an excellent MAO coating are voltage 230~260 V, frequency 300~500 Hz and duty cycle 30%~45%.

Four modified aluminide coatings were prepared on superalloy DZ38G, which include a two step co-cementation coating NiCr-CrAl and three one step co-cementation coatings Co-Al, Al-Si and Al-Ti. Then their microstructure and hot corrosion behavior in a salt melt of 25%NaCl (mass fraction)+75%Na₂SO₄ (mass fraction) at 900 ℃ were investigated. The results show that a continuously compact scale of corrosion products with good adhesion to the matrix could form on Ti-Al coating during corrosion, therefore, the Al-Ti coating may provide much better protectiveness to the alloy rather than the other three coatings in this kind of salt mixture.

ZnO/TiO₂ composite film was prepared on the surface of 304 stainless steel by sol-gel technique and spin coating method. The phase composition and microstructure of the as-prepared ZnO/TiO₂ composite film was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The effect of the preparation procedure and calcination temperature on the photoelectric property has been investigated and the photocathodic protection performance of such composite film for 304 stainless steel was also evaluated in 3.0%NaCl solution by using the electrochemical method. The results indicate that the composite film prepared by two-step procedure with proper calcination temperature exhibits excellent photo-electrochemical performance. The photocathodic protection property of ZnO/TiO₂ composite film for 304 stainless steel under UV light illumination is significantly superior to that of pure TiO₂ film and ZnO film respectively.

The microstructure and corrosion properties of Zn-5Al-xTi alloy have been investigated by OM, SEM, EDS and electrochemical tests etc. The results show that a small amount of Ti addition in Zn-5Al alloy refines the primary β-Zn phase and increases the percentage of the eutectic structure. With the addition of 0.15%Ti, almost all β-Zn phase disappears in the Zn-5Al-0.15Ti alloy and therewith which exhibits an entire eutectic microstructure. With increasing the Ti content to 0.2%, a new Al-Ti-Zn ternary phase appears in the alloy. The addition of Ti increases the corrosion resistance of Zn-5Al alloy. Among others, the corrosion rate and corrosion current density of Zn-5Al-0.15Ti alloy reach a minimum of 0.85 μgcm^-2d^-1 and 1.403 μA/cm² respectively, while the impedance at high frequency or the diffusion impedance at low frequency all reach a maximum. Uniform corrosion occurs for the Zn-5Al-0.15Ti alloy with entire eutectic microstructure.

Cu/Ni multilayered films were prepared by a two step electrodeposition method. The influence of the modulation wavelength and heat treatment condition on the alloying of Cu/Ni multilayered films were studied by means of SEM and XRD. The results showed that the Cu-Ni alloy coatings with well homogeneity in microstructure and composition can be prepared by the alloying of Cu/Ni multilayered films; the alloying process would be favored with the decreasing modulation wavelength as well as the increasing temperature and time of heat-treatment. Besides, the corrosion performance of coatings of copper, nickel and Cu-Ni alloy were comparatively evaluated by immersion test in NaCl solution. The results showed that the Cu-Ni alloy coatings exhibited much positive corrosion potential, smaller polarized current density and lower corrosion rate rather than the pure copper and nickel coatings.

The application of zinc injection at pressurized water reactors (PWRs) shows great benefits in reducing the radiation field and mitigating the primary water stress corrosion cracking (PWSCC) initiation and crack propagation of structure materials to a certain extent. The oxide film of Inconel 690 exposed to 300 ℃ dynamic high temperature water without/with 50 μg/kg Zn injection up to 1200 h has been investigated by XPS, SEM and EDS. It is revealed that the oxide film formed on Inconel 690 in the water with 50 μg/kg Zn addition is much thinner with grain size much smaller than that without Zn addition, while the distribution of grain size of the oxide film followed the Gauss function. The highest zinc concentration is found in the outer portion of the oxide layer close to the outer surface. Compounds ZnCr₂O₄ and ZnFe₂O₄ with low Gibbs energy were formed on the surface of the alloy in water with Zn addition, which make the oxide film much more stable than those in the Zn free water.

Without changing the content of the alloying elements C, Si, Mn, Cu and Al in an ordinary ductile cast iron, of which the influence of the addition of Cr and Ni on the microstructure, mechanical performance and the sea water corrosion resistance was studied by means of metallography observation, hardness and cutting test, weight loss test and polarization curve measurement in sea water, as well as surface EPMA analysis for the corrosion products. Accordingly an optimal chemical composition of that cast iron was acquired. The results showed that elements Cr, Cu and Al are beneficial to the formation of a thin and tightly adherent passive film on the surface, which can enhance the corrosion resistance of the alloyed cast iron. Element Ni can positively rises the corrosion potential and significantly reduce corrosion current density of the alloyed cast iron. As a comprehensive result, the alloyed cast iron with Cr content 0.6%~0.8% (mass fraction) exhibits not only better cutting performance, but also superior corrosion resistance in comparison with the ordinary ductile cast iron.

The electrochemical corrosion behavior of 316L stainless steel and B30 Cu-Ni alloy in saline groundwater with variation of electric conductivity, pH value and flow velocity was investigated by potentiodynamic polarization curves and EIS. The results showed that the corrosion current density and pitting sensitivity of B30 Cu-Ni alloy increased rapidly with the increase of the conductivity, while that of 316L stainless steel increased slowly. The corrosion resistance of 316L stainless steel was better than that of B30 Cu-Ni alloy. In acidic solution, B30 Cu-Ni alloy exhibited characteristic of uniform corrosion without appearance of pitting corrosion. With the increasing of pH value, pitting corrosion of B30 Cu-Ni alloy was promoted while that of 316L stainless steel was inhibited. As the flow velocity increased up to 1 m/s, the stability of the passive film of B30 Cu-Ni alloy was damaged, while that of 316L stainless steel was not affected. These results provide a reference to the choice of the metal materials for heat pump system.

A series of cathodic polarization experiments for DH36 steel has been performed with seawater flow in a range of flow velocities: 0.20, 0.40, 0.60, 0.80, 1.00, 1.20, 1.40 and 2.00 m/s in a pipe flow circulating seawater device. For each flow velocity, at least three different polarization current densities were chosen to perform galvanostatic cathodic polarization for 7 d. The results showed that the current density demand for an adequate cathodic protection (CP) increased with the flow velocity; the potential could be also polarized to achieve -800 mV vs the silver/silver chloride (seawater) reference electrode (Ag/AgCl [sw]) when the velocity was up to 1.00 m/s; however when the velocity was above 1.20 m/s, erosion-corrosion probably could occur even the polarization potential has achieved the protective potential; the calcareous deposits formed on the steel surface were most single magnesium-rich layers. Exceptionally, calcium-rich deposits could form on top of the magnesium-rich layer only when a very high current density was applied.

Effects of aging treatment at 540~580 ℃ on the corrosion resistance of a copper-bearing duplex stainless were studied by electrochemical measurement in culture medium with and without bacteria. The surface morphology of the biofilms and the corrosion products formed on the steels solution treated and aging treated at 560 ℃ were characterized by OM and XPS. The results show that in the culture medium without bacteria, but the proportion of coarse copper-rich phase in the corrosion products on the aged steel increases with the increasing aging temperature, correspondingly the corrosion resistance of the aged steels became worse; in comparison with those in the culture medium without bacteria, the corrosion resistance of the steels solution treated and aged at 540 ℃ is inferior, while of the steels aged at 560 and 580 ℃ is better in the culture medium with bacteria, correspondingly a thicker porous microbiological biofilm with low CuCO₃ content formed on the steel solution treated in the culture medium with bacteria, which possessed less protectiveness, while a thin and dense biofilm with high CuCO₃ content formed on the steel aged at 560 ℃, which could enhance the corrosion resistance of the steel.

Field exposure for carbon steel Q235 and weathering steel 09CuPCrNi-A was carried out in a site of typical urban atmosphere and a site of typical petrochemical environment respectively at Wuhan metropolis in the central China. Whilst the evolution of the formed rust layers on the steels in the initial stage of field exposure was characterized by SEM, electrochemical method and XRD. We found that the evolution of the early rust layers could be differentiated into two stages. The redox reaction was faster in the first stage. In the second stage, the reduzate Fe₃O₄ was accumulated and the oxidation process of Fe₃O₄ was suppressed with the growing of rust layers, thereby the electrochemical activity of the rust layers was enhanced.

According to the basic principle of fluid flow, mathematical models of erosion corrosion and cavitations flow phase transition are established, the internal fluid flow of the nozzle is numerically simulated and analyzed by Fluent software. The results show that the serious damage position of material caused by the erosion locates on the corner of nozzle inlet. However, the position suffered from the maximum shear stress will be near to the nozzle exit when the "super cavitation" phenomenon exists. For a given level of corrosivity of fuel used, the erosion degree increases with the increase of the viscosity, fluid velocity and inlet pressure of the fuel, as well as the corner radius of the nozzle inlet, and decreases with the increase of the back pressure. For a given inlet pressure and a flow rate, the erosion corrosion would be reduced and the fuel atomization would be facilitated when the viscosity and back pressure of the fuel as well as the corner radius of the nozzle inlet were reduced.