The sealing effect of REE on anodic film of aluminum alloy under electric filed is an effective non-toxic harmless measure. In this paper, the technology and the relevant mechanism of the sealing of REE on anodic film of aluminum alloy under electric filed are summarized. The research progress in this field is also summarized .The rational suggestion and feasible countermeasures of this field are put forward.

Imidazoline and its derivatives are one of corrosion inhibitors which have been successfully used for metal corrosion control. The recent researches about the inhibition mechanism of corrosion inhibitors and the related molecular simulation are reviewed in this paper, including quantum chemical study on structure-activity relationship of molecular, molecular simulation of corrosion inhibitor/metal interface and inhibition mechanism of inhibitors in different corrosive media etc. Finally, development directions of imidazoline corrosion inhibitors are discussed.

A bilayered enamel-ceramic composite coating, consisted of an inner layer of enamel-50 mass % corundum and an outer layer of enamel-50 mass % quartz, was prepared on nickel-based superalloy K38G by spray-sintering technique. The coating is dense with glaze surface and has good adhesion to the substrate. Its oxidation behavior at 1000℃ for 120 h was studied by means of thermogravimetry, SEM, EDS and XRD. Cristobalite, a high-temperature polymorph of quartz, and zircon and albite precipitates were detected in the as-prepared enamel-ceramic composite coating. In addition, Ni, Co and Cr were present in the inner layer of enamel-corundum. The mass gain of the coated alloy after 120 h oxidation was about 0.2 mg/cm², quite lower than those of NiCrAlY coatings. Most of the quartz particles in the coating transformed into cristobalite after oxidation tests. Besides, orthoclase was detected too. Ni-enrichment was observed in the outermost region of the outer layer, while Cr-enrichment was found in the inner layer close to the inner/outer interface. And Ni-, Cr-, Al-enrichment were found in the inner layer near the substrate either of the as-prepared samples or of the samples after oxidation tests.

The effect of temperature and Cl^- concentration on pitting corrosion of L360 steel in H₂S/CO₂ environment has been studied using methods of mass loss testing, SEM and XRD. The depth distribution of pits was analyzed with Gumbel first approximating function. The results showed that pitting corrosion tended to be more serious with the increase of temperature (from 40℃ to 70℃) in 10 g/L Cl^- solution. Pitting corrosion occurred in Cl^- solution with the concentration of 10×15 g/L at constant temperature, and uniform corrosion ccurred when the Cl^- concentration was higher than 20 g/L. As the temperature increased, corrosion products on the surface became looser and the protective property decreased. The measured maximum depth of pits followed the Gumbel first approximating function.

The high temperature oxidation resistance of HK40 alloys with different amount of Al in Ar atmosphere was investigated. The surface morphology and the phases in the oxide scale were analyzed using SEM and XRD, respectively. Experimental results indicated that after Al addition the formed Al₂O₃ scale on the alloy surface at high temperature was uniform, consequently improved the alloy oxidation resistance. The optimum high-temperature oxidation resistance was achieved with the addition of 6 mass% Al. The oxidation mass gains of the alloy complied with a parabolic law at 1100℃, and oxidation resistance of the allotys was significantly improved with the increase of aluminum content. At high temperature, the formed oxide scales consisted of Cr₂O₃, CrMn_1.5O₄, MnCr₂O₄ and Al₂O₃, and the amount of Al₂O₃ in oxide scales increased with the increase of aluminum content, while the presence of aluminum improved the surface homogeneity of oxide scale, and the content of Fe, Ni elements of the oxide scale is much lower than that of the alloys.

Constant load tensile test, electrochemical corrosion measurement and SEM analysis were adopted to study the sulfide stress corrosion cracking (SSCC) of  P110 steel in H₂S/CO₂ NACE standard solution. The results show that, in the initial stage of loading, the E _corr of P110 steel drops sharply and increases slowly again after reaching a minimum value. Then the E_orr increases to constant value until fracture occurs, and the brittle cleavage fracture appears correspondingly. When the content of CO₂ increasing to 17%, the E_corr of P110 steel decreases, the corrosion current increases, the process of SSCC is speeding up, and thereby complete cleavage fracture appears correspondingly. With the content of CO₂ further increasing, the _Ecorr of P110 steel increases slightly, and the corrosion current decreases, the time to fracture is extended. When the content of CO₂ increasing to 50%, small quantity of toughness dimples on the fracture surface appears correspondingly. This phenomenon has the relevance to the combination of competitive adsorption of H₂S/CO₂ on the surface of steel with tensile breakdown and regeneration of surface film on P110 steel in stress corrosion environment.

CO₂/H₂S induced corrosion behavior of P110 steel was investigated in high temperature and high pressure autoclave, and corrosion rate was measured by mass loss method. The corrosion product scale was analyzed by using scanning electron microscope(SEM), energy dispersive X-ray spectrometer (EDS) and X-ray diffractometers (XRD). And the resistance to hydrogen damage of P110 steel was tested by electrochemical hydrogen charging and NACE TM0177 A method, respectively. The results showed that the uniform corrosion rates of P110 steel are quite low, and there is no localized corrosion in CO₂/H₂S environments. But with the increase of the amount of hydrogen charging, the tensile strength, elongation and area reduction rate decrease for P110 steel. When charging enough, the fracture mode was changed from ductile fracture to brittle fracture. According to NACE TM0177 Standard A method, the samples fail. Therefore, when the H₂S exists, the service safty of P110 steel needs to be further improved.

Superhydrophobic TiO₂ nanotube arrays on pure Ti was prepared by surface-modification in Hexamethyldisilazane (HMDS) solution and its performance, surface morphology and composition were characterized by means of water contact angle measurement, energy dispersive X-ray spectrum (EDS) and scanning electron microscopy (SEM). The corrosion behavior of the superhydrophobic surface film was investigated with potentiodynamic polarization measurements and electrochemical impedance spectroscopy(EIS). The results showed that the superhydrophobic surface film significantly decreased the corrosion currents densities (I_corr), increased the polarization resistance (R_t) of Ti. Due to the air valleys and capillarity effects, the corrosion resistance of the material was improved remarkably.

The corrosion inhibition effect of the Cinnamomum camphor leaves extractive for carbon steel in 10% H₂SO₄ solution was investigated by using potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed that the Cinnamomum camphor leaves extractive had good corrosion inhibition effect for carbon steel in 10\% H₂SO₄ solution. The inhibition efficiency increased with increasing concentration of Cinnamomum camphor leaves extractive, and decreased with increasing temperature. The Cinnamomum camphor leaves extractive was a mixed-type inhibitor, and the adsorption of the effective corrosion inhibition component of Cinnamomum camphor leaves extractive on the carbon steel surface conformed with Langmuir adsorption isotherm equation. The addition of Cinnamomum camphor leaves extractive in sulfuric acid solution enhanced the apparent activation energy of the reaction on carbon steel, which made the corrosion inhibition effective.

The Ni-nano Al₂O₃ composite plating was prepared on SUS304 stainless steel. The distribution of Al₂O₃ particles in the composite plating was examined. The proper amount of particles in the solution, current density as well as stirring speed for electroplating was then determined. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to characterize the microstructure, composition and phase constituent of the plating. The results showed that the Ni-Al₂O₃ composite plating was very compact with small grain size, good adhesive to the substrate and excellent corrosion resistance. Furthermore the high-temperature oxidation resistance of the composite plating was higher than that of the Ni plating.

Friction stir welding (FSW) for 2024 aluminum alloy sheets was conducted by different processing parameters. The microstructure of the surface and the corrosion behavior in EXCO solution of joints were investigated. The correlation between the micro-hardness profile and the corrosion sensitive region was discussed. The results show that grains in the shoulder active zone (SAZ) are obviously refined. With increasing the rotation speed, the spans of heat-affected zone (HAZ) widens, furthermore, the hardness of the SAZ increases and the corrosion resistance of this region enhances. When the rotation speed is 1500 r/min and weld speed is 1000 mm/min, the plasticity metal flow is more intensive, and the hardness value of the SAZ comes up almost to that of the base metal, therewith, only pitting corrosion occurred in the joint after being immersed 10 h in EXCO solution. Compared with the base metal, the softened zone coincides with the corrosion sensitive region. However, there is not strict correlation.

The flow-accelerated-corrosion performance of 20 steel, Q345R steel and 304 stainless steel was investigated in condensed water by using a flow accelerated corrosion test apparatus with three electrodes measurement. Scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) were employed to investigate the thickness, microstructure of corrosion scale. The results showed that the corrosion rates of the test steels were different with a decrease ranking as 20 steel>Q345R steel>304 stainless steel. Their microstructure of corrosion scale had different morphologies. The corrosion scale of Q345R steel was thicker than that of 20steel, but much better of compactness of the former ones.

The corrosion behavior of 316L stainless steel in seawater was investigated by measurements of critical pitting temperature, cyclic anodic polarization and electrochemical impedance spectroscopy under different temperature. The results indicated that two 316L specimens with different grain size showed similar critical pitting temperature. The increase of seawater temperature led to the linear decrease of pitting potential and repassivation potential. The pitting resistance of the fine grain steel decreased larger than that of coarse grain steel with temperature increasing, the latter had a higher pitting potential about 60 mV at 85℃. Compared with the coarse grain steel, the surface of  passive film formed on the fine grain steel showed more defects and thereby which showed a shorter incubation time of pitting corrosion at 65℃.

The effect of cetyl trimethyl ammonium bromide (CTAB) on corrosion behavior of AZ31 Mg alloy in 3.5% NaCl solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The surface morphology of corrosion product on Mg alloys was observed by SEM. The results showed that the corrosion rate of AZ31 Mg alloy was reduced by addition of CTAB within a concentration range of 2000~3500 mg/L in NaCl solution, and the corrosion rate in NaCl solution with 3500 mg/L CTAB was the lowest. The mechanism may be attributed to the adsorption of CTAB on the surface of Mg alloy, which blocked the anodic dissolution. Meanwhile, the corrosion product with less defects was formed on the Mg alloy by the addition of CTAB, and this reduced the path for penetration of corrosive media and increased the charge transferred resistance. Thus, the corrosion rate of Mg alloy was improved by addition of CTAB in NaCl solutions.