The single-phase (α) and duplex-phase (α+γ) nano-crystalline coatings have been fabricated on glass substrate by DC magnetron sputtering. The electrochemical corrosion behavior of the two NC coatings in solutions of 0.25M Na2SO4 + 0.05M H2SO4 and 0.5M NaCl + 0.05M H2SO4 was investigated by using potentiodynamic polarization, EIS and SEM. The results showed that there was a large difference in the corrosion behavior between the single-phase (α) and the duplex-phase (α+γ) nano-crystalline coatings. The duplex-phased coating is shown to have exhibited a lower localized corrosion resistance and possessed a less stable passive film than the single-phase coating. A similar two-layer semiconductor passive film was formed on both coatings; however, a great increase in carrier densities could be responsible for the low stability of the passive film on the duplex-phase coating.

The corrosion processes of LY12CZ aluminium alloy and LY12CZ with aluminium overlayer LB2 were studied by electrochemical impedance spectroscope (EIS) under anodic potential steps in 0.1 mol/L NaCl solution. According to the characteristics of EIS, the electrochemical equivalent circuit was established. The corrosion mechanisms of the two materials were further analyzed. The results show that the main EIS characteristics of the two materials are similar during the corrosion processes. Their Nyquist plots both consist of two capacitive arcs. During the pitting propagation of LY12CZ with aluminium overlayer, the radius of capacitive arcs in Nyquist plot increased temporarily, because the oxide films between in LY12CZ and aluminium overlayer inhibited the pitting propagation.

The deposition characteristic of electroless plating Ni-P on Gr/Al composite surface and coatings corrosion resistance are investigated for the particularity of Gr/Al composite surface in this paper. During forming nucleus of action points, chemical displacement reaction is taking place in the dipping zinc solution on the Al substrate, but nucleus of action points are adorpted on the reinforcement graphite fibers surface, because Al is part of the second surface and graphite is part of the third surface. After formation nucleus for depositing nickel, Ni-P alloys would deposit on the Gr/Al composite surface. It is result that Ni-P coating blocked off the circuit for the electrochemical reaction in galvanic couples, and the non-crystal coatings had not sensitive grains boundary for the corrosion reaction, the corrosion resistance was improved by Ni-P coating.

The protective film was prepared by immersion magnesium alloy AZ31B in silane solution. The surface morphologies of specimen were analyzed by using SEM、Optical Microscope. The bond adherence between silane film and substrate was researched by FTIR. The corrosion resistance of film was analyzed by salt water immersion and potentiodynamic polarization test. The results show that a very thin and transparent film that was smooth and compact was prepared on the AZ31B magnesium alloys by immersion in silane solution. The silane film has effected polarization voltage of AZ31B magnesium alloys slightly, however the polarization current decreased to 1.024 mA/cm2 for the specimen compared with the bare magnesium alloys (4.489mA/cm2). So the corrosion resistance of magnesium alloys was greatly improved by silane treatment.

In this paper, the spreading behaviors of micro-droplets with and without the electrochemical polarization were investigated under the cyclic wet-dry conditions of 50% RH and 90% RH at 25℃. The results indicated that there was unobvious influence of the wet-dry cycles on the formation and spreading of micro-droplets in a condition without the electrochemical polarization. Under the external polarization, with the advance of the wet-dry cycles, the areas covered with micro-droplets alternately expanded and dwindled, and the polarization current Ip and polarization resistance Rp changed impulsively. The maximum of Ip in each cycle increased gradually with the increase of the wet-dry cycles and the corresponding maximum of Rp followed a reverse changing rule. Under cyclic wet-dry conditions, it showed a closed relation between the spreading of micro-droplets and corrosion current. They were influenced and promoted with each other.

The feasibility of the electrophoresis on micro-arc magnesium alloy was analyzed, and the electrophoresis technology was optimized and simplified. The complex coatings with different colors were finally developed. The complex coatings were studied by acid-resistant and alkali-resistant tests afterwards, and the result demonstrated that the corrosion resistance of the processing magnesium alloy was greatly improved under acidic and alkaline circumstance. It will surely provide necessary academic and technical backups for magnesium alloy’s extensive application.

An oxidation protective SiC/Si-MoSi2 / MoSi2 coating was prepared on graphite substrate by silicon infiltration and slurry sintering. Microstructure and anti-oxidation property of multi-layer coating were studied. Results showed that the inner layer，the intermediate transition layer，the outer layer is made of SiC，Si and MoSi2，MoSi2，respectively，and the functionally gradient coating was formed. The as-received coating characterized by excellent thermal shock resistance can effectively protect the graphite for long life at 1700 ℃ in air.

Grey system theory and the method of time series analysis are combined to create a grey combination model. Box-Jenkins model is introduced to analyze random component. Grey combination model is applied to predict change trend of eroding velocity for pipe, and the performance of which is proved to be good by an example. The model is compared with other methods, then got a conclusion that the precision of the model is superior.

The inhibition effect and inhibition mechanism of drug product of quinolones for mild steel(A3) in 1mol/L HCl were studied by weight-loss method、polarization curve and EIS. The results showed that the inhibition efficiency of drug product of quinolones on mild steel(A3) are 95％and 92％in 1mol/LHCl with the effective concentration of 3.5×10-3mol/L, respectively. They can inhibit both anodic and cathodic processes of the corrosion reaction from the potentiodynamic curve. The study for the influence of temperature on the inhibition efficiency indicated that the increase of temperature will decrease the inhibition efficiency.

Technological process and operation conditions for electroless nickel plating of magnesium-lithium alloys were studied, as well as the structure and composition of plating were analyzed along with the thickness and microhardness were measured．Results showed that the plating had excellent adhesive strength and corrosion resistance．

The non-toxic antifouling coating, because of having no environmental hazard, would become a trend in the field of antifouling coating. A review was given on the two main research directions: changing the quality of resin and using the non-toxic antifouling agent. The recent progress was described from the aspects of species, action mechanism and characteristics of the non-toxic antifouling coatings. The problems concerning the non-toxic antifouling coatings and the settlements were also elucidated. Moreover, its development trend is prospected.

ABSTRACT: Aluminum sacrificial anodes have been widely used in the protection of iron structures, which are positioned in or around the sea, such as ships, platforms, and so on. While the efficiency of Al-anodes is decreased due to the passive film formed on the aluminum surface. So, it is necessary to investigate high efficient aluminum anodes. Thus, one should have quite understanding on the activation of aluminum in seawater, in order to optimize the alloying composition. In this paper, the activation behavior of aluminum in seawater and the effects of depassivators are summarized systematically.