Potential distributions of atmospheric corrosion caused by salt particle deposition were investigated using scanning Kelvin probe technique. The results indicate that the changes in potential distribution depended on the type of the salts and the relative humidity of the environment. At lower relative humidity, the potential distribution over the metal with salt particl deposition remained uniform. When relative humidity is higher than RHoss(Relative Humidity over Saturated Solution),however, the potentials around the salt particle deposition shifted negatively, forming a lower potential valley , and then the potentials outside the valley gradually moved positively, leading to volcano type of the heterogeneous potential distribution. This phenomenon can be observed on zinc and steel with the salt particle deposition such as sodium sulfate, sodium chloride and potassium chloride. The nonuniform potential distribution caused by the deposition of salt particle built-up anode and cathode which forms corrosion battery on the metal surface. Then, the atmospheric corrosion was initiated and propagated.

In this paper, study on the initial electro-deposition behavior of Ni-P alloy on the surface of 45 steel shows that it is influenced by the microstructure of matrix material. As the pearlite in it contains cementite phase and has high crystal boundary density, the nucleation and growth of deposits prefer to occur at the pearlite at the beginning during deposition on the surface of annealed 45 steel. The coating exists in form of nano-polycrystal layers composed by gathering of nano-sized crystals. With plating time going on, the nano-polycrystal gathering grows in two dimensions, and the new nano-polycrystal layer appears simultaneously on the formerly formed nano-polycrystal surface.

A study on the effect of IMC-80-Q(quaternary alkynoxymethyl amine) and IMC-871-W(imidazoline) on the electrochemical behavior and inhibitor properties of N80 steel in 3% NaCl saturated by CO2 at 25±10C was carried out by means of weight loss and electrochemistry techniques including EIS, potentiodynamic polarization and linear polarization. The sharp decrease of anodic current density ia, positive shift of corrosion potential (Ecorr) and anodic desorption were observed in inhibited solutions.The electrochemical parameters Rp,Cd and Rt exhibited extreme values at certain concentrations of two inhibitors,150mg/L for IMC-80-Q and 100mg/L for IMC-871-W ,respectively.IMC-871-W had better inhibitor properties than IMC-80-Q.The weight loss test at 7m/s showed that the cumulative mass loss was decreased sharply for solutions containing IMC-80-Q, compared with inhibitor-free brine, and extreme-value-phenomena of concentration was not observed up to 300mg/L.

Stress corrosion cracking (SCC) of 304 stainless steel in high temperature water media containing H3BO3 and Li+ was studied using slow stain rate test (SSRT). One group samples were annealed (heated at 1050℃ for 60 min. then water quenched) and the other group samples were sensitized (annealed sample then heated at 650℃ for 120 min. and water quenched). Temperature for SSRT is 300℃ or 250℃. Water Media contained 1200mg/L H3BO3, 2mg/L Li+, 2.5 mg/L or 5mg/L Cl- in order to simulate pressurized water reactor condition. The results proved that sensitized material, chloride concentration in the water and higher test temperature showed SCC susceptibility more severely for 304 stainless steel. The fractography proved susceptibility clearly.

Based on the H2S stress corrosion test for x65 pipeline steel, three-dimensional elastic-plastic finite element model was established. By the numerical analysis of the FEM, stress field and concentration distribution character of hydrogen from the crack tip were obtained. This paper surveyed the microstructure of the joints and studied on the mechanical performance of X65 pipeline steel. It provided experiment basis for the affecting factors of stress corrosion cracking. Moreover, the critical stress intensity factor KISCC and crack propagation velocity were obtained by the wedge-open loading constant displacement specimens. The result of stress corrosion was verified by finite element numerical analysis.

Two kinds of empirical learning methods based on artificial neural network(ANN),i.e., double layer perceptron(DLP) model and Elman feedback(EF) model,have been used to analyze SCC data and predict the SCC susceptibitlity of austenitic stainless steels in high temperature water(HTW). The results indicated that DLP model could not converge after long training epochs while EF model could reach a steady value within limited training epochs for the SCC data of stainless steels(SS).The SCC susceptibility fo 304SS and 316SS in HTW depends on the parameters such as temperature(T), dissolved O2 content(DO), chloride ion content ([Cl-]) and electrode potential(E). The threshold value(ThV) for SCC used in the EF model affected the prediction ratios. For THV<=0.6, the ranges of prediction ratio were ca.0.66-0.90for method Ⅰ(including the data to be predicted) and 0.60～0.79 for method Ⅱ(excluding the data to be predicted) for 304SS, ca.0.81～0.98 for method Ⅰ and 0.78～0.90 for method Ⅱ for 316SS. The curves of mean value of prediction ratios show that the prediction ratios have the characteristics of normal distribution and the best ThV is 0.5. The EF model is a very useful tool for qualitatively predicting the SCC behaviour of austenitic stainless steels in HTW.

Set up an artificial neural net and train it with the data provided by four seawater corrosion experiment stations. After the succession of training , the net can predict any kind of metals corrosion status on 16years and the comparative error is not beyond 20 percent. Compare with the way of function regression, this result is more accurate. The net can also trained with the anomaly data that can not regress to any function and the net can make an accurate prediction.

In the present paper, EIS was used to study ultra-fine TiO2 modified epoxy anti-corrosion coating. Experimental results show that the Nyquist plot of ultra-fine TiO2 modified epoxy anti-corrosion coating is a single capacitive loop, and its equivalent circuit is parallel connection of polarization resistance and coating capacitance. After half year, immersion in 3.5% NaCl solution, the polarization resistance keeps higher than 108Ω.cm2, coating capacitance lower than 10-10F/cm2 and water absorption is 0.12.These show that the ultra-fine TiO2 modified epoxy anti-corrosion coating has excellent anti-corrosion performance and anti-water performance.

The nickel-based alloy powder was sprayed to a steel substrate using HVOF, and the corrosion resistance of the coatings was evaluated using electrochemical tests, so as to offer an experimental basis to expand a promising applied field of HVOF in aqueous medium. The results show that NiCrBSi coating has excellent corrosion resistance in alkali solution, because the surface can keep in a self-passivation condition. The corrosion current of the coating in sour solutions is bigger than that in 3.5%NaCl, and the corrosion caused by Cl- is serious than that caused by SO42-. The reproducibility of the test results can be improved when the 3.5%NaCl aqueous solution is acidified with acetic acid, and using a corrosive medium that keep the tested surface in an active-dissolved condition can get the same purpose. The more less the defects in the coating, the better the corrosion resistance. Improving the quality and reducing the porosity of coatings is the key to get the coatings with high corrosion resistance.

The article studies the dynamic mechanical behavior of water-solubilized damping coating with interpenetrating polymer networks of core-shell type of thermoset polyacrylic by the dynamic viscoelastic spectrum. The result shows: by the two-step method and by the changing of main unit ratio MMA/BA and the changing of the weight fraction of DVB, we can synthesize a series of acrylic ester soap-free hydrosol with interpenetrating polymer networks(IPN) of MMA/BA" core-shell" type. IR symbol of the interpenetrating polymer networks shows all the monomer have taken part in the polyreaction . The composition system has very good dynamic mechanical behavior. The interpenetrating function exists among the interpenetrating metworks of this system, and the interpenetrating function depends on the ratio of MMA/BA and the dosage of DVB. When MMA/BA is 4/6 and DVB is 0.1%, the coating film has good dynamic mechanical behavior, and it can also reach the essential demand of the coating film. When add HMMM into hydrosol to mix coating and heat and solidify it , the partly chemical crosslink occurs, so the coating film has good damping behavior.

In this paper, the effect of Ca2+ in the form of bilfilm on the surface of carbon steel, the corrosion extent of MIC and the efficacy of bactericide were investigated via AFM, EPMA and EIS. The result shows that Ca2+ can promote the growth of SRB, increase the compact of bilfil and decrease the sensitiveness of carbon metal to MIC. But at the same time Ca2+ also decreases the sensitiveness of SRB to biocide which brings many difficulties to the prevention and cure of SRB.

The electrochemical behavior in erosion-corrosion of carbon steel in flowing liquid-solid double phase solution was studied with self-made flow loop simulating apparatus. The experimental results showed that erosion-corrosion rate in flowing double phase 3.5% NaCl solution containing 5% sand increases markedly with increasing flow velocity. But it was not found that the erosion-corrosion rate-decreased region which happened in flowing single phase solution existed. The erosion-corrosion process of carbon steel in flowing liquid-solid double phase solution is still controlled by cathodic oxygen diffusion process. Once cathodic current was impressed on carbon steel, the erosion-corrosion rate of carbon steel decreases abruptly because the corrosion electrochemistry factor is restrained and the synergism is weakened. It was verified that corrosion electrochemical factor plays a dominant role in erosion-corrosion.

A sensor for monitoring corrosion of brass tube of power station is designed and made. The Ag/AgCl wire is used as reference electrode and the pt-Ir alloy wire as assistant electrode. Insulatedly, the two electrodes are filled in a tailor-made EVA(polymer of ethylene and acetic acid ethylene) tube whose diameter is one millimeter. So the sensor can be put into long tube for monitoring .A simulation cell is made for simulating the sondition of power station. The used and not used brass tubes are cut into same length for making cell. The inside of brass tube is used as work electrode, the tap water is used as electrolyte. The sensor is applied to measure polarization resistance(Rp) of the two brass tubes of cell. The results show that the sensor can be used for monitoring the corrosion of brass tube.

Some quantitative measurement methods for exfoliation susceptibility of aluminium alloys are introduced, including electrochemical impedance measurement, electrical resistance survey and wedging force measurement of corrosion product. The basic theories and features of these methods are described. The effects of heat teat treatment, such as aging and annealing, on exfoliation susceptibility of 2′′′, 5′′′, 7′′′ series and Al-Li alloys are reviewed. The effect mechanisms, such as nonuniform distribution of aging microstructure and difference of electrochemical properties among the constituent phases, are illuminated. Meanwhile, some aspects of next research objectives are outlined.

Since the Kelvin probe technique has been introduced into the studies of atmospheric corrosion, it has been paid increasing attention by corrosion scientists in the past decade due to its ability to measure the metal surface covered by very thin electrolyte layer, the corrosion potential and its distribution yet without touching the metal and electrolyte. In this paper, the history and properties of this technique were reviewed, also the applications on delamination of organic coatings and corrosion of metals under thin electrolyte were discussed.