Comparing between immersed and cyclic wet-dry conditions, the deterioration processes of the organic coatings on carbon steel surface have been comparatively studied by using electrochemical impedance spectroscopy (EIS). The wet-dry cycles were carried out in the alternating conditions by immersing in a 3.5% sodium chloride solution and drying at 25° and 50% RH for 4 h respectively. Coating resistance, R_f, coating capacitance, C_f, and double layer capacitance, C_d, were monitored continuously and separately under above two conditions. The percentages of the interface active area, A_w, were estimated from the obtained double layer capacitance, C_d. According to the EIS characteristics, the entire deterioration processes under two above-mentioned conditions can be divided into three main stages, consisting of the medium penetration into coatings, corrosion initiation and corrosion extension underlying coatings. In comparison with the immersed, the wet-dry cycles greatly accelerated the entire deterioration process; especially the corrosion initiation and the corrosion extension periods, leading the paint system lose its anti-corrosive performance in a short period. However, the underlying substrate corrosion of the cyclic coatings was far less serious than the immersed; even the delaminating area was seven times more than the immersed. The acceleration mechanism of the coatings and underlying metal corrosion under wet-dry cycles was discussed based on the above results.

Two kinds of ionic liquids, hydrogen sulfate and tetrafluoroborate of 1-octyl-2-pyrrolidonium ([Hnop]HSO₄/BF₄), were prepared. Their inhibition and adsorption behavior on mild steel in 1 mol/L hydrochloric acid solutions were investigated by mass loss and electrochemical methods, respectively. The results indicate the ionic liquids act as the mixed type inhibitors. The inhibition efficiency of ionic liquids increases with the increasing inhibitor concentration, decreases with increased temperature and reaches more than 90% for [Hnop]HSO₄ in 0.8 mmol/L at 303 K. The adsorption of [Hnop]HSO₄ on the surface of mild steel obeys the Langmuir adsorption isotherm via physicochemical adsorption, which is a spontaneous exothermic process.

Electrochemical testing, and quantum chemistry calculations were used to study the corrosion inhibition mechanism of L-methionine, L-cystine, L-cysteine in 1 mol/L sulfuric acid system. The results of linear polarization, Tafel extrapolation and EIS showed that inhibition efficiency of L-methionine and cysteine increased with the increase of the concentration among 0.0001 mol/L~0.1 mol/L. And these three amino acids adsorption in carbon steel is provided by the amino acids to provide electronic, air-rail track, two coordination bonds to bonding.

The composite polyurea coating system were made with the solvent-free epoxy sealing coating and the polyurea coating on the surface of the concrete sample. The adhesion strength of the polyurea coating on the surface of concrete was measured. To understand the reasons for the adhesion failure of the polyurea coating on the surface of the concrete sample, the characteristics of the interface between the polyurea coating and the concrete surface were analyzed thoroughly with the help of surface topography, infra-red spectrum, and electron spectrum. The results showed that the adhesion failure resulted from the damage of the physical adhesion between the polyurea coating and concrete; and the failure of “solvent-free epoxy sealing coating + polyurea coating” system resulted from both the damage of the physical adhesion between the coating and concrete, and the damage of cohesion of the sealing coating itself. It was suggested that this solvent-free epoxy sealing coating improved the adhesion of the coating system and enhanced the strength of the concrete surface because of the special internal structure formed between the solvent-free epoxy sealing coating and the polyurea coating.

2-undecyl-N-carboxymethyl-N-hydroxyethyl imidazoline (UHCI) was investigated as a corrosion inhibitor for carbon steel in 8 mass% amidosulphuric acid solution using weight loss test, electrochemical methods and scanning electron microscopy (SEM) . The weight loss test results showed that the inhibitor was an excellent inhibitor for carbon steel in acid media with an inhibition efficiency of 90.12% and a corrosion rate of 0.6370 g/(m²• h) at the mass fraction of 0.4%. The polarization curves indicated that the inhibitor behaved as a mixed type inhibitor. The impedance spectra of carbon steel electrodes changed from one time constant into two time constants when the inhibitor added into the blank solution. The absorption of the inhibitor was found to follow the Langmuir adsorption isotherm and the mechanism was a mixture of chemisorption to physisorption. The results from SEM also give evidence of the effective inhibition of UHCI on carbon steel corrosion in amidosulphuric acid.

The influences of additives on plating rate, coating quality and bath stability were investigated to develop THPED-EDTA•2Na thick copper plating process. The plating rate is obviously increased by proper amount of L-arginine, and its proper dosage is 0.15 mg•L^-1; the coating quality is greatly improved by proper amount of PEG and ferrous potassium cyanide in spite of slight decrease of plating rate, and the proper amount are 150 mg•L^-1 and 20 mg•L^-1, respectively. The stability of bath is enhanced by all these additives and the stability time of bath in which mixed additives is added reaches the highest of 5 h at 80℃. The plating rate is 7.10 μm•h^-1 and the backlight level achieves 10th grade under appropriate conditions after plating for 15 min. The coating is red, bright and uniform, the sedimentary layer is cubic copper and the crystal of copper coating is mainly assigned to the (111) face.

The aim of this study was to examine the oxidation behavior and electrical conductivities of ferritic stainless steels STS444 coated with element Y for planar SOFC (solid oxide fuel cells) interconnects at 750℃. The effects of the main elements (Fe,Cr,Mn and Si) and the rare earth element Y on the growth of oxide scale and the high temperature electrical conductivity of STS444 alloy were studied using glow discharge spectrometer （GDS） and secondary ion mass spectroscopy （SIMS） techniques. The results indicated that the reactive element effects of element Y improved noticeably the oxidation resistance and electrical conductivities, and it can be possibly used as the candidate material for the SOFC interconnects.

Ni-SiC nanocomposite coatings were prepared by means of the conventional electrocodeposition method. The technological parameters that make the nanocomposite coatings have a better corrosion resistance in 0.5 mol/L NaCl solution were preliminarily determined by using electrochemical impedance spectroscopy test（EIS）. By comparing the charge transfer resistance of the coatings, it is shown that coatings prepared with current density range of 15 mA/cm²~20 mA/cm² and SiC content of 6 g/L have better corrosion resistance. The structure of coatings were investigated by scanning electron microscopy（SEM）. The corrosion resistance of Ni-SiC nanocomposite coatings and pure nickel coatings in 0.5 mol/L NaCl solution and 1 mol/L HNO₃ solution was analyzed by immersion tests, electrochemical impedance spectroscopy and polarization curves. As immersion time prolonged in 0.5 mol/L NaCl solution, the charge transfer resistance of Ni-SiC nanocomposite coatings and pure nickel coatings reduced rapidly at initial stage and then became stable at later stage. Moreover, the charge transfer resistance of Ni-SiC nanocomposite coatings were higher than those of pure nickel coatings at the most of the immersion time. In addition, the charge transfer resistance of coatings containing SiC particles were 2 to 5 times higher than those of coatings without SiC particles when they were immersed in 1 mol/L HNO₃ solution for 0.5 h. So the SiC nano-particles were helpful to improve the corrosion resistance of the coatings, which increased with increasing SiC content in the coatings. The effect of SiC nano-particles on the corrosion resistance was discussed in details.

The electrochemical impedance spectroscopy (EIS) of X100 steel in water-saturated acidic soil was studied. The results show that pitting corrosion occured after soak in Yingtan saturated soil water for 104 hours, and the Nyquist diagram had two time constants, a capacitive loop at high frequency represented the reaction, and an inductive loop at the low frequency for representing adsorption or the pitting nucleation period of the inductance. Diffusion control results in the increasing of impedance because of low media conductivity during the initial corrosion period. The accumulation of corrosion products on the electrode surface hinders proliferation of reactive ions which also can result in impedance increasing with the test time. The corrosion scale is porous and forms activated regions which result in the decrease of impedance. Concentration of harmful Cl ^-  in the corrosion products initiates localized pitting and brings reactance.

Leaching behavior of Sn-3.5Ag-0.75Cu and Sn-0.75Cu lead-free solder alloys in a NaCl-Na₂SO₄-Na₂CO₃  mixed solution as simulated soil was investigated and compared with that of Sn-37Pb alloy. The results showed that leaching amount of Sn from the three solders increased with reaction period. The most leaching amount of Sn was found for Sn-0.7Cu solder alloy. However, Sn leached from Sn-3.5Ag-0.75Cu solder alloy was depressed by adding Ag element. The leaching amount of Ag, Cu and Pb elements also increased linearly with increasing time. However, the relatively less amount of leached Ag and Cu was measured. The product on the leached solder alloy surface was identified as Sn₄(OH)₆Cl₂ and SnO. Many cracks and pits were found in the product on Sn-0.75Cu alloy surface, while the product layer on Sn-3.5Ag-0.75Cu alloy was rather compact. For Sn-37Pb alloy, some product had spalled from the surface. Based on the experimental results, it was supposed that the phase formation and morphology of surface product were responsible for the difference of leaching kinetics for these three solder alloys.

Antibacterial activity of polyaniline and the mechanism in water was studied in this paper. The results indicated that the microorganism index of treated sewage water for urban by doped polyaniline could reach to the level of reclaimed water. Due to the dissolving out of doping acid the doped polyaniline could raise the COD (chemical oxygen demand) of wate and result in secondary pollution. In comparison, the antibacterial rate of emeraldine base polyaniline could reach up to 99% without contamination. The result of analysis by KI iodine-blue spectrophotometry reveals that the activity of active oxygen created by oxidation of polyaniline may be another antibacterial mechanism during treament of water.

The protection dimension of scratched zinc phosphate/epoxy coating was studied by means of electrochemical impedance spectroscopy (EIS), electrochemical noise measurements (EN) and scanning electron microscopy (SEM). The experimental results of EN, EIS and SEM revealed that zinc phosphate could inhibit the corrosion of the scratched epoxy coatings; the protection effect was gradually weakened with increasing scratch dimension from 0.4 mm, 1.0 mm to 2.0 mm. The mechanism of the inhibition of zinc phosphate pigment was analyzed based upon the shot noise theory combined with Gumbel distribution function. It showed that the corrosion growth probability of the metal under the coating decreased with the addition of zinc phosphate.

Metal dusting corrosion is a disintegration of metallic materials, which is dependent on carbon activity and pressure of atmosphere, temperature of circumstance, alloying component and so on. Diffusion of carbon into metal such as Fe, Ni and Co and their alloys plays a key role, meanwhile, external loading is an important factor. A brief discussion about coupling models of mechanics-chemical is made in the present work. Activity volume model is used to investigate the influence of external force on carbon diffusion. The results show that tensile stress promotes diffusion of carbon into metal, while compressive stress restrains it into metal.

In the present investigation, the mechanism and hazard of hot corrosion for metal materials were reviewed. Based on analyzing laboratory testing techniques of hot corrosion, turbine blades and vanes of some gas turbine engine were introduced to study the evaluating method for hot corrosion resistance capability of turbine components and materials with burner-rig test. It was shown that burner-rig test was competent for evaluating hot corrosion resistance of gas turbine components and materials. It should be the most efficient method on evaluating marine environment hot corrosion resistance of gas turbine components and materials in laboratory so far, and the objective authorities of anti-corrosion designing and processing could be provided by this kind of test method.

The failure pressure of long-distance gas pipeline was predicted based on nonlinear mapping function of artificial neural network. The effects of pipe diameter, pipe wall thickness, material yield strength, radial corrosion rate, longitudinal corrosion rate, defect length and pit depth on the pipeline failure were analyzed comprehensively. In order to illustrate the generality of neural network, the network was trained using sample training set from six corroded pipelines with different diameters. The result showed that the neural network can be a more accurate and convenient method to predict pipeline failure.