With the development and utilization of polar routes and rich resources in polar regions, the ice covering of hull and all kinds of equipment of navigation ships brings serious safety risks to the safe navigation of polar ships. Thus, research of anti-icing coatings for polar ships and offshore equipment gradually becomes a hot research topic nowadays. Superhydrophobic coatings have excellent ice-resistance properties. However, its practical application is limited to some extent. This paper presents a review on the icing theory, the theoretical models of superhydrophobicicity, and the anti-icing properties of superhydrophobic interfaces. Then the application of superhydrophobic coatings with different preparation methods in the field of anti-icing is discussed and summarized. Finally, aiming at the shortcomings of superhydrophobic coating in deicing, the strategy of superhydrophobic coating with photothermal and electrothermal functions was proposed, and the current research status was comprehensively introduced.

Carbon capture, utilization and storage (CCUS) technology is recognized as the main means to realize the low-carbon utilization of fossil energy, and will inevitably be developed and applied under the current energy consumption structure and energy strategic layout. This paper summarized the corrosion failure of metal pipes in CO₂ injection wells that are prone to accidents in the process of CO₂ enhanced oil recovery and CO₂ storage in the CCUS technical process. The researches on corrosion cracking, crevice corrosion and microbiological influenced corrosion are reviewed and summarized. The main influencing factors and anti-corrosion methods of metal pipes in CO₂ injection wells are also summarized and analyzed. The main research directions in this field in the future are also prospected.

As the "blood" circulatory system of coal gasification plant, the water system frequently faces corrosion and leakage problems due to the complex environment with high solid content, corrosive media and high temperature and pressure, which seriously affect the safty of production operation. The corrosion mechanism of the water system was explained, which included erosive wear, cavitation, electrochemical corrosion triggered by CO₂, H₂S, HCOOH and other acidic media, chloride stress corrosion induced by Cl^-, and multiple corrosion caused by $NH^{+}_{4}$, CN^- and other nitrogen ions. The corrosion-prone sites of the water system were also introduced. Moreover, combined with the actual research of coal gasification devices, the protective measures against corrosion were analyzed and summarized in term of the material selection, device/process design and monitoring management. Establishing an intelligent corrosion risk prediction system for equipment/pipeline was proposed. These strategies shed light on improvement of corrosion status in coal gasification industry.

A survey reveals that the community of fouling organisms in the seawater testing pool of a marine environmental test station set at Sanya Bay on Hainan Island showed features of fewer species, lower density and smaller size of individual, which is quite different from those of the of natural seawaters at the vicinity and even other tropical sea areas. By investigating the ecological distribution of the species of fouling organisms in the test pool, the pool structure and the water quality, as well as the relevant meteorological events, it is found that the existence of concrete-made seawater test pool with designed structure can significantly change the flow state of the original sea area and even the ecological environment conditions of the natural sea area at the vicinity, as a consequence, the concentrations of α-chlorophyll and nitrate within the pool were only 1/5-1/6 of that in the natural seawaters at Sanya Bay. In addition, high intensity scour may emerge in the testing pool during storm surge, strong heat effect may generate on the pool wall by low tide exposure, and there even exists extreme natural disasters such as heavy rain lasting more than 5 h. As a result of all of the above factors, there are few species of the community of fouling organisms may form in the tidal zone area of the cement wall of the pool. The dominant species are the Ostrea mordax in the pool. Besides, on the surface of non-toxic test plates that have been immersed for more than five years, only rare tube-dwelling polychaetes and Xiamen oysters attach. It is also found that the corrosion rate of non-passivable ferrous metal materials in the pool was much faster than that in natural tropical marine areas at Sanya Bay. This study illustrated that man-made facilities set in natural sea area could greatly affect the composition and structure of fouling organisms community, and thus affect the degree of accuracy of the detection- and evaluation-results of the antifouling performance and corrosion process of materials.

To further enhance the corrosion resistance of high manganese steel, the effect of adding micro-alloying elements such as Cr, N, and Al on the corrosion process and electrochemical properties of fully austenitic high manganese steel (HMS) in acidic salt spray environment was investigated. The corrosion performance and corrosion products of the HMS were assessed by means of mass loss method, field emission scanning electron microscopy (SEM), and white light interferometry, and the evolution of electrochemical properties of two HMSs (namely the micro-alloyed HMS (WH-HMS) and the un-alloyed HMS (PT-HMS)) was examined by electrochemical techniques such as dynamic potential polarization and AC impedance spectroscopy. The results show that with the prolongation of corrosion time, the formed oxide scale on Micro-alloyed HMS becomes much more compact and has much better corrosion resistance for long-cycle corrosion. The corrosion kinetics of the micro-alloyed high Mn steels follows ΔW_WH= 4.44202 × 10^-4t^0.9618, in the contrast, the un-alloyed HMS follows ΔW_PT= 8.74985 × 10^-4t^0.67759. The electrochemical results show that the corrosion current density of the two HMSs gradually decreases with increasing corrosion time, and the capacitive arc gradually increases. After 240 h corrosion, the micro-alloyed HMS presents the capacitive arc much greater than that of the untreated HMS, whereas the corresponding corrosion rate of 1.925 × 10^-3 mm/a for the former is less than that of the later. The main reason for the better corrosion resistance of the micro-alloyed high manganese steel is that the micro-alloying of Cr, N, and Al reduces the precipitation of carbides within high manganese steel, the formed oxide scale is much compact with good adhesion to the substrate, therefore which can effectively hinder the attack of Cl^- and thus provide better protectiveness for the micro-alloyed HMS.

An imidazole Schiff base (MIX) corrosion inhibitor was synthesized via processes of amidation, dehydration cyclization, and quaternization at different temperatures with oleic acid, diethylenetriamine, n-butane iodide and cinnamaldehyde as raw material. The corrosion inhibition performance and mechanism of MIX on Q235 steel in 1.00 mol/L HCl were systematically investigated by means of mass loss measurement, electrochemical testing, and surface analysis methods, as well as theoretical simulations. The results showed that the corrosion inhibition efficiency determined by mass loss method, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (Tafel) were 98.64%, 96.93%, and 99.15%, respectively for adding a dose of MIX 2 mmol/L in the 2.00 mmol/L HCl solution, indicating that MIX can exhibit excellent corrosion inhibition performance in HCl environments. Electrochemical testing and isothermal adsorption models indicate that MIX is a cathodic corrosion inhibitor that can spontaneously adsorb on the surface of Q235 steel, following the Langmuir adsorption isotherm model. MIX can form a stable protective film on the surface of Q235 steel, further hindering the charge transfer rate within the corrosion system. XPS, EDS and FT-IR analysis confirmed that MIX molecules may be adsorbed on the surface of Q235 steel. Density functional theory (DFT) showed that the active site of MIX was phenyl, and the N atom on the imidazole ring. Molecular dynamics (MD) further confirmed that MIX may be adsorbed on the surface of Q235 steel. MIX can exhibit excellent corrosion inhibition performance in HCl environments, mainly due to the formation of a stable protective film on the surface of Q235 steel, which reduces the charge transfer rate within the corrosion system.

With excellent electrical and thermal conductivity, TP2 copper has a wide range of applications in industrial production process. During the practical production process, a large amount of organic acid pollutants containing carboxylic acid ions will be generated. Meanwhile, as a result of the defects of TP2 copper and the impact of moisture and corrosive media in the external environment, the content of organic acid pollutants in operating ambient of TP2 copper is at the high level, which may accelerate the occurrence of organic acid corrosion on the surface of TP2 copper. In order to simulate the organic acids induced corrosion behavior of TP2 copper in industrial environments, the TP2 copper was assessed via immersion tests in solutions with different organic acid concentrations temperature-cyclically, by means of measurements of mass loss Tafel polarization and electrochemical impedance, as well as SEM characterization. The results show that in comparison to the acetic acid containing atmosphere, TP2 copper exhibits stronger corrosion tendency in the formic acid containing ones, while the higher the organic acid concentration, the much severe the corrosion of the TP2 copper. In addition, the combination of the organic acid containing atmosphere and SO₂ pollutants may cause much severe corrosion damage of the TP2 copper surface, and the higher content of the SO₂ pollutants, the severe the corrosive conditions. Besides, much severe corrosion and complexity of the corrosion behavior emerged on the surface of the TP2 copper in the atmosphere of co-existance of SO₂ pollutants and with formic acid rather than that with acedic acid.

The corrosion inhibition performance of the cationic surfactant dodecyl dimethyl lbenzyl ammonium chloride (1227) on cold rolled steel in 0.10 mol/L Cl₃CCOOH trichloroacetic acid solution was investigated by mass loss measurement, electrochemical test, scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle tester. The results show that 1227 can effectively suppress the corrosion of cold rolled steel in 0.10 mol/L Cl₃CCOOH solution. The inhibition efficiency of 40 mg/L 1227 is as high as 97.4% at 20^oC. The higher the corrosion inhibitor concentration, the higher the corrosion inhibition efficiency, and the higher the temperature, the lower the corrosion inhibition efficiency. The adsorption of 1227 on CRS surface follows Langmuir adsorption isotherm, and the type of adsorption is a mixture of physical and chemical adsorption while chemisorption as the main effect. The potentiodynamic polarization curve shows that 1227 can simultaneously inhibit both the cathodic- and anodic-reactions, and so 1227 is a mixed inhibitor and its action mechanism is "geometric covering effect". In the Nyquist diagram, along with the increase of 1227 concentration, the capacitance arc and the charge transfer resistance all increase, therewith, the inhibition effect increases. The result of SEM and AFM analysis proves also that 1227 can effectively retard the corrosion of the steel in Cl₃CCOOH solution. The contact angle results show that the addition of 1227 enhances the hydrophobicity of CRS surface.

In order to investigate the applicability of the proposed indoor accelerated test spectrum, which aims to simulate the low temperature marine environment in the polar region, and the corrosion mechanism of low alloy steel exposed in the real polar low temperature atmospheric environment, therefore, the Ni-Cr-Mo-V steels were subjected to indoor accelerated test in lab and to outdoor exposure test in Zhongshan station at the polar region respectively, then the corrosion behavior of the tested steels was comparatively studied by means of mass loss measurement, scanning electron microscope, and laser confocal microscope. The results revealed that the corrosion rate of the steel is 11.3 μm/a, and the corrosion products are composed of Fe₃O₄, γ-FeOOH, α-FeOOH and β-FeOOH. The presence of the large amount of β-FeOOH indicates that the rust scale formed in low temperature environment has poor protectiveness. The low temperature atmospheric corrosion is mainly uniform corrosion. The freeze-thaw cycle causes the alteration of electrolyte concentration on the surface of test steel, which results in the formation of pitting corrosion beneath the rust scale. During the freeze-thaw cycle, the alternation of stresses caused by the cyclical solid-liquid phase transition of the water in the rust scale and the difference of the thermal expansion coefficient between the rust scale and the metal matrix could lead to the cracking of the rust scale.

The oxidation behavior of Fe-20Ni-20Cr-ySi (y = 0, 1, 3, 5, mass fraction, %) alloys were studied in 1 atm O₂ at 900^oC for 24 h. After oxidation, Fe-20Ni-20Cr alloy without Si addition formed a complex oxide scale on the surface with poor protectiveness. When the Si content increased from 1% to 3%, a transition from internal to external oxidation of Si occurred. Therefore, additions of Si can significantly improve the oxidation resistance of the austenitic Fe-20Ni-20Cr alloy. Both Fe-20Ni-20Cr-3Si and Fe-20Ni-20Cr-5Si formed an amorphous SiO₂ layer on the Cr₂O₃/alloy interface, and this continuous amorphous SiO₂ layer provided an effective barrier to prevent the outward diffusion of Fe, Ni and Cr, as well as the inward migration of oxygen. A comparison of the oxidation behavior of alloys with different Si contents indicated that Fe-20Ni-20Cr-3Si has the most excellent oxidation resistance properties.

The prepared rare earth cerium modified graphene/waterborne epoxy resin composite coating was applied on the surface of Q235 steel by spraying, rolling and brushing respectively, then of which the structure and corrosion resistance in 3.5%NaCl solution were studied. The results showed that as nano particles, rare earth cerium or CeO₂ was chemically deposited on the surface of graphene, while the modified graphene was uniformly distributed in epoxy resin as small lamellae. The applied composite coating on Q235 steel presents a stacked structure of graphene lamellae, while the fractured surface of the coating presents a pattern of river-like silve stripes. The formation of the composite coating applied by different methods may be described as that: the spraying method relies on the high-speed moving gas to impact the atomized coating droplets onto the surface of the substrate and quickly gather and spread them into a film, which improves the combination of the coating to the substrate while purifying the surface of the substrate. The roller coating method relies on the wire rod coater, and the brush coating method relies on the soft brush to combine the coating with the substrate. Thus molecules in the coating are easy to stack, and mocropores may easy form on the surface. The adhesion of the coating was measured to be 0-1, the hardness was 2H, and the surface roughness was ~2 μm. The corrosion rate is 1.565 × 10^-4-5.889 × 10^-3 mm/a. It is found that the coating applied by spraying method has the best comprehensive performance.

Oxidation behavior of FB2 steel for steam turbine and FB2 steel coated with three different coatings was comparatively investigated in 630^oC/25 MPa supercritical water (SCW). The three coatings are supersonic flame spraying Ni-Cr coating (SFS-NiCr), glass shot peened SFS-NiCr and emery belt grinded SFS-NiCr. Their oxidation mass change was intermittently measured by electron balance, while their microstructure and phase composition were characterized by means of SEM, XRD and XPS before and after oxidation test. Results show that the oxidation kinetics curve of FB2 material deviated from the parabola due to the spallation of the formed oxide scale during the oxidation process. The oxidation kinetics curves of coatings prepared by different processes seriously deviated also from the parabola. A double-layered oxide scale formed on FB2 steel, consisting of an Fe-rich outer Fe₃O₄, Fe₂O₃ and a Cr-rich inner oxide layer. The oxide scale formed on the three coatings are mainly composed of chromium-rich oxide. The phase composition of the oxide scales formed on FB2 steel and the three coatings changed with the increase of oxidation time. Finally, the oxidation mechanism of FB2 steel and three coatings in supercritical water was discussed.

Q235 steel samples were buried for one year in soils of test sites in 100 substations, which distributed at different areas in Anhui province presenting various typical soils of peculiar characteristics and meteorological conditions. Afterwards, the corrosion rates and corrosion products of the test samples were assessed via mass loss measurement, SEM, EDS and XRD. The results showed the rust scales formed on the samples were composed mainly of Fe₃O₄, Fe₂O₃, γ-FeOOH and α-FeOOH, but their relative amount varied by different soil test sites. The S^2- content in the soils of some soil test sites is high enough to generate FeS as the corrosion product of the samples. It indicates that the physiological activities of microorganisms have an effect on the soil corrosion behavior of the Q235 steel. In general, according to the test results from several typical soil test sites of Anhui province, Q235 steel samples present an average soil corrosion rate of 0.053 mm/a, and their corrosion grades are mostly “moderate”. The soil test sites where the samples have a high corrosion rate are mainly located in the areas along the Changjiang River and/or the industrial pollution areas. In terms of the Spearman correlation analysis, the correlation degree sequence of the index of soil texture and soil physicochemical properties affecting the one year soil corrosion behavior of the Q235 steel is: pH value > soil texture > soil resistance > salt content > water content > redox potential > Cl^- concentration.

Mg-alloys as the lightest metallic structural materials have many excellent properties, but their corrosion resistance is poor. Thus the corrosion behavior of Mg-alloy in different service conditions need to be acquired. Especially, the composition of pollutants and meteorological factors in different atmospheric environments may affect the corrosion behavior of Mg-alloys. In this paper, the corrosion behavior of the extruded EW75 Mg-alloy in Shenyang industrial atmosphere was investigated by atmospheric exposure at Shenyang atmospheric test station located at 123°26' east and 41°46' north. After exposure for different durations, the test alloys were characterized by means of SEM, EDS and Raman spectroscopy in terms of their surface and cross sectional morphology and the chemical composition of corrosion products. The results show that the dusts containing soluble salts in the industrial atmosphere were deposited on the surface of the extruded EW75 Mg-alloy and form round-shaped corrosion products, which show good protection for the corresponding magnesium matrix; the potential difference between the fine precipitation phases and α-Mg is low, which exhibits weak micro-galvanic effect, resulting in the formation of uniform corrosion. In addition, the corrosion rate of Mg-alloys in Shenyang atmosphere is greatly influenced by seasonal variations. Compared with the low temperature and low humidity winter, the corrosion rate of the extruded EW75 Mg-alloy is significantly higher in the high temperature and high humidity summer.

To solve the problem of poor adhesion of the coating/metal interface in deep-sea environments, active epoxy resin (ZA-EP) was prepared by grafting histamine onto the epoxy resin E44 molecular chain, which can facilitate the formation of chemical bonds with metal substrate. Histamine heteroatoms in ZA-EP can form a shared lone pair electron with the vacant orbital of iron/iron oxide, which can promote the formation of the complex of Fe²⁺ ions with the resin, thus improving the interfacial bonding strength between the coating and the metal substrate. Compared with the ordinary epoxy coating, the adhesion of the coating containing active resin was significantly improved: for example, the adhesion of epoxy coating increased from 6.02 MPa to 15.36 MPa after the addition of 3% ZA-EP. In addition, the test results in the simulated deep-sea water under alternating pressure show that the saturation water absorption of the 3% ZA-EP/EP coating is the lowest, only 1.6% after one cycle test in 3.5%NaCl solution (by high static pressure 3.5 MPa for 12 h + constant pressure 0.1 MPa for 12 h). The EIS results after 3 cycle test (72 h) showed that the impedance of the 3%ZA-EP/EP coating remained stable. In other words, histamine modification may facilitate the formation of a chemical bond at the coating/metal interface, enhances the adhesion of the coating, thereby, the ZA-EP/EP coating has a good protective performance.

Phosphate coatings, composed of silica sol modified Al(H₂PO₄)₃, ceramic fillers and additives, are prepared and then applied on Ti-6Al-4V alloy, which are further characterized by means of XRD and Fourier transform infrared spectrometer, as well as corrosion test beneath deposits of salt-mixture in vapor flow at 650^oC. The results show that silica sol can promote the formation of glass phase while the phosphate coating curing. When the mass ratio of silica sol to Al(H₂PO₄)₃ reaches 1∶1, the mixture of silica sol to Al(H₂PO₄)₃ may produce_{a film of complete glass phase which ensures the formation a completely dense phosphate coating. The modified phosphate coating provides excellent corrosion resistance to salt-mixture in vapor flow at 650^oC, and the chemical stability of the film and filler is the vital factor of the corrosion resistance of the modified coating. The coating is still dense after 100 h of corrosion at 650^oC in such environment, and rare corrosion products of elements of the matrix alloy appears. As one filler of small amount, the Al flakes and their corrosion products are arranged parallel to the matrix in the coating, which can effectively prevent the diffusion of harmful ions such as Cl^- to the matrix, meanwhile which can react with Na2SO4 so that inhibit the intrusion of molten salt into the coating and the corrosion of Ti-alloy matrix.}

Waterborne polyurethane (WPU) coating, a new kind of green material due to its excellent wear resistance, flexibility, low-temperature resistance and chemical medium resistance, has been widely attached attention to the field of marine corrosion protection. In this paper, hydrophilic modification of the hydrophobic silica (SiO₂) aerogel was carried out by urea aldehyde modification. Then, the unmodified- and modified-SiO₂ aerogels as filler were added into the WPU coatings with doses 0.5%, 1% and 2%, respectively, aiming to improve the anti-corrosion properties of WPU coatings. The functional groups and microstructure of SiO₂ aerogel were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). These results proved that SiO₂ aerogel was successfully modified by urea-formaldehyde. The anti-corrosion properties of coatings with different fillers were studied by contact angle test, electrochemical impedance spectroscopy (EIS), adhesion test and salt spray test. The results showed that the adhesion of the coating was significantly improved after adding hydrophilic-modified SiO₂ aerogel. When 1% hydrophilic modified SiO₂ aerogel was added, the adhesion of the composite coating was improved by 36% correspondingly, the low-frequency impedance modulus of the composite coating increased above 6 × 10⁷ Ω·cm² after immersion in 3.5% NaCl solution for 70 d. There was no obvious bubbling phenomenon on the surface of the composite coating with 1% hydrophilic modified SiO₂ aerogel after the 480 h salt spray testing, which showed its best anti-corrosion performance. Thus, it is concluded that the hydrophilic modification of the hydrophobic SiO₂ aerogel by the urea aldehyde modification can improve the dispersibility of the hydrophobic SiO₂ aerogel in the WPU coating, the interface compatibility with the coating and the barrier and shielding effect of the SiO₂ aerogel on corrosive ions. Furthermore, the corrosion resistance of the WPU coating is improved.

The CO₂-induced corrosion of 5Cr steel in a magnetically driven autoclave with a simulated oilfield produced water at different temperatures and pressures was assessed by means of XRD, SEM and EDS as well as electrochemical measurement and wire beam electrode (WBE) technique. The results show that with the increasing temperature, the corrosion potential of the electrode as a whole has different degrees of negative shift, the corrosion tendency and the corrosion rate of 5Cr steel all increase; meanwhile, the capacitive impedance arc with a large radius emerged in the electrochemical impedance spectrum of 5Cr steel, the film coverage degree and compactness of the corrosion product increase, the charge transfer resistance tends to increase, and the resistance of the electrochemical reaction increases significantly. The formation and expansion of the local anode area on the surface of 5Cr steel has the tendency to cause pitting corrosion, which may be preferred to form at defects on the film formed in the early stage of corrosion. The corrosion products are gradually deposited on the inner wall of the pit, then a protective surface layer with obvious Cr enrichment is formed on the inner wall of the pit, thereby, the original pitting corrosion area is transformed from the active sites on the original anode to the cathode area, therefore, the pitting expansion is inhibited. The polar transformation phenomenon of the corrosion current of the local sites of the 5Cr steel beneath the corrosion product film occurs, namely, from cathodic ones turn to anodic ones, and the defects in the corrosion product film make the 5Cr steel substrate corroded, resulting in the appearance of anodic current.

In view of the fact that there is no common recognized standard in accelerated corrosion test for the simulation of marine environmental corrosion, and the existing accelerated corrosion test method is not well satisfactory. Therefore, on the basis of our previous research, a solution with addition of higher amount of H₂O₂, while phosphate buffer solution as stabilizer was proposed for the accelerated corrosion test of AH36 ship hull steel. The testing results were compared with those of the natural environment exposure test at Xisha sea area of Hainan province. It follows that there is a good correlation between the accelerated corrosion test in the solution containing 0.6 mol/L NaCl, 1.8 mol/L H₂O₂ and 0.2 mol/L H₃PO₄-NaH₂PO₄ buffer solution (pH = 2.5) and the natural environment exposure test in Xisha sea area; Non-uniform overall corrosion occurs on AH36 steel, The corrosion rate of AH36 steel increases first and then decreases. The corrosion products are composed of iron oxides and hydroxyl oxides, which have a good inhibition effect on medium-and long-term corrosion. The formation of insoluble salt Fe₃(PO₄)₂(OH)₂ enhances the protectiveness of the rust scale. H₂O₂ promotes cathodic depolarization and accelerates the corrosion of steel by shortening the reaction process and increasing the dissolved oxygen in the solution. Compared with the natural environment exposure test in Xisha for 1 a, the accelerated corrosion test results in an accelerated corrosion rate about 40 times of natural marine environment exposured ones. This study explores a way for rapid evaluation of marine environmental corrosion of engineering steels.

Mixtures of cement-based material with the addition of synthetic calcium silicate hydrated (C-S-H) was prepared, then the effect of internal admixture of C-S-H on the evolution of the combination of chloride ions with the cement paste during aging process was investigated by means of XRD, TG-DTG, SEM and EDS. The results showed that the quantity of free chloride ions in the test pieces tended to decrease and then increase with aging process. At the ages of 7, 14 and 21 d, the quantity of free chloride ions in the cement paste with C-S-H was higher than that without C-S-H. This was due to the relatively larger particle size and smaller specific surface area of C-S-H, which reduced the total specific surface area of C-S-H in the cement paste and reduced the combination amount of C-S-H to chloride ions; in addition, the addition of C-S-H to the cement paste could promote the hydration of cement and increase the pH value in the early hydration period, and the high pH value is not conducive to the adsorption of C-S-H on chloride ions; and there is no Friedel's salt generation in the early hydration period of the cement paste mixed with C-S-H, so that weaken the chemical combination ability for chloride ions. At the age of 28 d, Friedel's salt was generated in the cement paste with addition of C-S-H, thus the amount of chemical combination of chloride ions increased, so the free chloride ion quantity of the two groups of cement paste was more similar. Due to more SiO₂ existed in the cement paste with C-S-H at 28 d, the pozzolanic reaction to generate C-S-H with low Ca/Si and the decrease in pH value affecting Friedel's salt stability, the amount of free chloride ions increased significantly at 35 d.

The corrosion behavior of rebar steels such as HRB400 plain carbon steel, 304 austenitic stainless steel and 2304 austenitic-ferritic duplex stainless steel in an artificial solution, which aims to simulate the fluids in pores of reinforced concrete serving in marine environments, was comparatively investigated by means of measurements of open-circuit potential, electrochemical impedance spectrum, dynamic potential polarization curve and Mott-Schottky curve etc. The results showed that the corrosion potential of the three rebar steels in the simulated solution increased continuously, the impedance modulus and phase angle peak width increased gradually, and the maximum phase angle shifted to the low frequency direction. Mott-Schottky curve measurement results showed that the point defect density in the passivation film of HRB400 plain steel was high, and that in the passivation film of 2304 duplex stainless steel was minimal. The critical chloride ion concentrations for HRB400 plain steel, 304 stainless steel and 2304 duplex stainless steel are in the range of 0.02-0.03, 1.5-2.0 and 3.5-4.0 mol/L, respectively. While the excellent resistance to chloride-induced corrosion of 2304 duplex stainless steel was mainly due to the lower point defect density and compact structure, as well as the enrichment in Cr, Ni, Mo and other corrosion-resistant elements of the passivation film on the steel surface, which enable the passive film stronger repulsive effect on the Cl^- ions.

The corrosion performance and microstructure of ZM5 Mg-alloy before and after rolling were comparatively studied by hydrogen evolution measurement, mass loss method, electrochemical impedance spectroscopy (EIS), dynamic potential polarization measurement, XRD and SEM. The electron work function of different microstructures was numerically simulated through first principle analysis. The results show that rolling causes an obvious preferred orientation for ZM5 Mg-alloy. The corrosion mass loss and hydrogen evolution of ZM5 Mg-alloy decrease significantly after rolling, while the polarization resistance increases obviously. These all indicated that the corrosion resistance of the rolled ZM5 Mg-alloy is better than that of the cast one. The simulation results show that the rearrangement of α-phase enhances the electronic work function of the Mg-alloy.

The isothermal oxidation behavior of GH5188 superalloy at 1100^oC was studied by means of intermittent weighting, SEM and XRD. The results show that the main components of the formed oxide scale are Cr₂O₃ and MnCr₂O₄. The oxidation behavior can be approximated by parabolic law. The addition of La can help the alloy to form a continuous, compact and stable oxide scale of Cr₂O₃, improve the adhesion between the oxide scale and the alloy matrix, therewith enhance the high temperature oxidation resistance of GH5188 superalloy. However, with the increase of La content, the high temperature oxidation resistance of the alloy will decrease, the high temperature oxidation resistance of GH5188 alloy can be improved effectively only by adding proper amount of La (0.029%-0.060%).

The corrosion behavior of 5083 Al-alloy under magnetic field was studied by immersion test, electrochemical measurement, scanning electron microscope (SEM), energy spectrum analyzer (EDS) and electrochemical workstation, et al. The results indicated that the magnetic field could affect the motion of charged particles in the corrosive medium and inhibited the effect of destroying effect of Cl^- on passivation film. The applied magnetic field could rise the free corrosion- and pitting corrosion- potentials, and reduce the corrosion current density of 5083 Al-alloy. At the same time, the number and size of pits under magnetic field were lower than those without applied magnetic field. Magnetic field can reduce the pitting sensitivity and corrosion rate of 5083 Al-alloy. The inhibition effect is enhanced with the increase of magnetic field intensity.

The corrosion performance of carbon steel and three kinds of high-strength steels is comparatively assessed via outdoor exposure in marine atmosphere of the South China Sea in a test site at Wenchang area of Hainan Province, which provides data support and theoretical basis for the development of steels resistant to atmospheric corrosion in the South China Sea. Four kinds of steel, Q235B, Q350EWR1, Q355 and Q345NQR2, were selected as the testing materials. Outdoor corrosion tests were carried out for half a year and one year respectively, and the tested steels was characterized by means of mass loss measurement, metallographic observation and electrochemical analysis. Serious uniform corrosion occurred on the surface of the four steels. Based on the analysis results, the corrosion resistance of the four kinds of steels in the marine atmosphere of the South China Sea is ranked as the following sequence: Q355 > Q345NQR2 > Q235B > Q350EWR1.

ZnAlMg coated steel plates, as the substrate for anti-corrosion and decorative coatings, have to experience thermally baking in automobile manufacturing processes, which may affect the microstructure and corrosion resistance of the coating, but such effect was not studied yet. In this study, the ZnAlMg coated steel plates were heat treated at temperatures in the range of 150^oC to 250^oC for 10 min respectively so that to reproduce the baking effect. Then the variation of surface- and cross sectional-microstructure, phase constituents and corrosion behavior of the ZnAlMg coating before and after heating were assessed by means of scanning electron microscope (SEM), and X-ray diffractometer (XRD), as well as electrochemical technology and neutral salt spray test. The results show that with the increasing heating temperature, the eutectic structure in the ZnAlMg coating gradually coarsens, and oxides rich in aluminum and magnesium are formed on the surface of the coating. When heating at 175^oC, a large number of oxygen is detected on the eutectic structure and surface of the coating. When heating at 250^oC, the surface of the initial solidification structure of the coating becomes rough, while the gray phase in the eutectic structure gradually evolves from lamellar structure to granular structure, and a large number of oxidation products of Al, Mg and Zn appear on the surface, among which the oxides of Mg and Al are the main ones. The electrochemical test results show that with the increasing heating temperature, the polarization resistance and charge transfer resistance of the ZnAlMg coating increase but the corrosion current density decreases continuously. The results of neutral salt spray test show that the corrosion mass loss of the ZnAlMg coating decreases gradually with the increasing heating temperature. Compared with the as received ones, the corrosion mass loss of the ZnAlMg coating heat treated at 250^oC decreased by 17%. It was indicated that the improvement of corrosion resistance of the ZnAlMg coating may be related to the coarsening of eutectic structure and the formation of oxides rich in Al and Mg on the surface.

Mg-15Li-6Al alloy was prepared by vacuum induction melting and then the alloy was subjected to solution treatment plus air cooling or water cooling respectively. The phase constitution and microstructure of the alloys (as-cast, solution treatment plus air cooling or water cooling), were analyzed by means of X-ray diffraction analysis (XRD) and scanning electron microscope (SEM). In addition, the corrosion behavior of the three alloys was studied by gravimetric and electrochemical tests. The results show that the three-state alloys are all mainly composed of β-Li with a little of second phase AlLi, and the fractions of secondary AlLi precipitates in the alloys decrease in the following order: as-cast, solution treatment + air cooling and solution treatment + water cooling. The alloy after solution treatment plus water cooling is almost composed of single β-Li phase. On the contrary, the corrosion resistance of the three alloys follows the sequence: as-cast < solution treatment + air cooling < solution treatment + water cooling. Relative to the as-cast alloy, the free corrosion potential increases by 480 mV and the corrosion current density decreases by three orders of magnitude for the alloy solution subjected to solution treatment plus water cooling. The solution treatment makes more Al to dissolve back into β-Li, and subsequent fast cooling strongly suppresses the precipitation of AlLi. Therefore, the number of micro galvanic couple of AlLi and β-Li decreases, resulting in marked improvement of corrosion resistance.

Corrosion and hydrogen absorption of zirconium alloy cladding for PWRs is one of the main causes for cladding embrittlement and breakage failure. Therefore, rapid and accurate determination of hydrogen concentrations in zirconium alloys is of great importance to assess the integrity of the cladding. In this paper, we used the RH600/LECO hydrogen analyzer to measure the hydrogen concentration data for several samples of Zr-Sn-Nb cladding, meanwhile the corresponding data of hydrogenated area fraction were acquired by cross-sectional microscopic image measurements. On the bases of the two group of data, a formula was proposed to figure out the distribution of hydrogen concentrations in Zr-Sn-Nb cladding, namely the so called cross-sectional metallography method. This method was validated by using a large amount of known data from the existing literatures. The results showed that the hydrogen concentration values measured by the cross-sectional metallography method were highly accurate, and the error between the hydrogen concentration value and the nominal value is less than 6%.