Precipitation at grain boundaries of Cu-Ni alloy semirigid tubes exposed to seawater took place along with corrosion peeling of the surface oxide film, and the alloy's intergranular corrosion sensitivity increased significantly as a result of the precipitation process. According to TEM observation, the precipitates were product of spinodal decomposition and possessed diffraction pattern of alternate bright/dark strips with widths less than 50nm. The presence of precipitates caused intergranular brittle fracture of the material when tensile test was conducted. Its tensile strength slightly increased but the corrosion resistance of the tube was considerably impaired. The precipitation could be attributed to the change of stress condition in the material. The diffusion of alloy elements along grain boundaries towards surface film resulted in coarsening of the precipitates.

An array electrode composed of 64 steel wires and a potential imaging system were developed as a new electrochemical technique for probing the corrosion potential distribution at interface of polymeric coating/metal. The measuring technique was described, and the availability of the technique was examined. The novel data related to the corrosion behavior at the interface were obtained and the effects of defects in the coating on its degradation were discussed. The potential imaging demonstrated the existence of inhomogeneities in the coatings, including intrinsic defects or damage in service (artificial defects). Corrosion preferentially initiated at the defect sites. The anodic sites surrounding cathodic area and the development process of corrosion reaction were in situ imaged for the first time for organically coated steel system. The relevant and direct information provided by this unique technique would be very helpful for further understanding some important physicochemical processes associated with degradation of coated metals.

The finite element method was applied to calculate the potential distribution and current distribution on a cathodically protected steel pipe pile. In the calculations, the pipe pile, includion both the submerged and buried sections, was considered as a whole. The effects of some factors were examined, such as water resistivity, coatings, spacing between the pile and anode, as well as anode length. The results thus derived could be recommended for reference in the cathodic protection engineering design.

The EIS of rebars immersed in simulated pore solutions of concrete with different pH values and concentrations of chloride ion was measured. The characteristics of EIS of rebar in periods of stable passivation, pit incubation and pit propagation were studied. The EIS of rebar in stable passivation was a single capacitive arc with one time constant on impedance plane. An inductive component was observed in low frequency range during pit incubation period, and the impedance plane composed of two capacitive loops during pit propagation period. The correspoding equivalent circuits were proposed respectively, which could interpret the corrosion mechanism of rebar in simulated pore solutions.

The effect of magnetic feild and Cl- on anodic polarization behavior of iron in neutral 0.5mol/L Na2so4 solution was studied using potentiodynamic method. It was shown that iron in Na2SO4+Cl-solution exhibited active- passive-transpassive characteristics in the presence or absence of magnetic field, although Cl- in the solution would hinder the formation of passive layer. The applied magnetic field would cause shift of passivation potential Ep and flade potential EF towards noble direction, increase the critical current density for passivation imax and the passive current density imin, and narrow the passive region. A synergistic effect of imposed magnetic field and Cl- on breakdown of the passive layer was reported.

The effect of stress on the initiation and propagation of corrosion fatigue cracks for type 316L stainless steel in Hank's physiological solution was studied. The open circuit potential was not affected by dynamic stress, but the pitting potential decreased with the increase in stress. Pitting corrosion occurred more easily under the effect of stress and the area of higher stress concentration showed higher pit density. Under the coaction of stress and corrosive medium, several corrosion fatigue microcracks might initiated intergranularly at the pit bottom. One of them became the main crack and propagated transgranularly due to stress concentration at the crack tip. The fatigue striation and secondary cracks were observed on the fracture surface.

The influences of lead tartrate and tetrabutylammonium bromide (TBAB) on corrosion of zinc in KOH solutions were studied by using electrochemical techniques. The experimental results showed that the anodic dissolution of zinc and hydrogen evolution were inhibited by the reduction of Pb2+ on the active spots of zinc surface. It was found that TBAB mainly inhibited the anodic reaction by adsorption on some special spots of zinc surface. It was also found that Pb2+ and TBAB had an obvious synergistic effect on the inhibition of the anodic dissolution reaction of zinc. The desorption of these inhibitors from zinc surface was discussed.

Colourful conversion films were formed on zinc surface with cathodic polarization method from a molybdate-phosphate type aqueous solution. It was found from the results of salt spray corrosion tests that the golden film exhibited excellent anticrrosive performance. The results of XPS and AES analyses showed that the thickness of the golden film was about 75nm and Mo existed as Mo(VI) in the outer layer of the film. The relative atomic percent contents (A.C.%) of the golden film calculated at the constant elemental composition section on the AES profile curves were O 56.9%; Mo 26.8%; P 11.0%; Zn 5.3%.

The corrosion kinetics and scale structures of two Fe-Ni-Cr alloys containing 18 wt% and 39% nickel respectively were investigated in gassous mixtures of H2S/H2/CO2 at 600℃. The difference in scale structures due to different nickel contents was shown mainly in the outermost layers: with FeS for the 18wt% Ni alloy, while porous and dark(Ni, Fe)S for the 39 wt% Ni one. Both alloys had a middle layer of FeCr2S4 and an inner layer of Cr3S4. The corrosion of the lower nickel content alloy obeyed parabolic law, while that of the higher nickel content alloy showed irregular kinetics. Sulfur pressure affected the 39 wt% Ni alloy more than the 18 wt% Ni alloy. The weight gain of the lower nickel content alloy exceeded that of the higher nickel content alloy.

A comprehensive corrosion database in Chinese containing corrosion data for 26 metals and 81 non-metals in about 1000 corrosives, was designed and established. The database had more than 10 ways of inquiry and possessed a series of functions such as library maintenance and printing. C and C++ programming languages were used for database management system and user's interfaces respectively. The data were organized as a relational database. Xbase database structure and indexed file were adopted. The mapping from four-dimesion to two-dimesion was realized to simplify the system. Compressed sparse matrices by indexed table were employed as data storage mode. The advantages of this database include simple software supporting environment and convenient operation. Users were only required to select the items in menu and there was no need to input any characters.

Phase stability diagrams of quaternary hot corrosion type could be constructed on the basis of calculations of ternary mixed environment type diagrams. For both systems the condensed phases were considered to be the reaction products of the metal with two components in the gas phases, while for the hot corrosion type a condensed phase of the Na-O-S system was regarded as the reactant. The equilibrium lines and the triple points in the phase stability diagrams were calculated and selected by the free energy changes associated with the assumed reactions.

The microstructure and corrosion resistance to salt spfay and salt water immersion (3% NaCl) of batch hot dip aluminized coatings containing Si and RE were studied. The tests indicated that addition of 1-7% Si and 0.05- 0.35% RE into the melted Al bath markedly improved the corrosion resistance of the coatings. But excessive RE would impair the improvement. With increasing temperature of salt water the corrosion rate of both Al coating and Al alloy coatings containing Si and RE increased remarkably, and for the Al alloy coatings the increase in corrosion rate was less than that for Al coating. The beneficial function of Si and RE in the corrosion resistance of the coatings was discussed.

By electrochemical method and weight loss measurements, the inhibition and adsorption behaviour of N-alkyl lauryl amide (NALA) on carbon steel in sulphuric acid solution was studied. NALAexhibited reasonable corrosion inhibition performance. When concentration of NALA exceeded 0.60mmol/L, its inhibition efficiency reached more than 90%. Polarization measurements showed NALA mainly hindered anodic process. Its adsorption process was an exothermic reaction, and could be attributed to chemical adsorption. There was a transition point on isothermal adsorption curve (θtrans=90.5%). When θ<θ trans, Temkin adsorption isothemal equation was followed. When θ>θ trans, Frumkin adsorption isothermal equation was obeyed.

The effect of deformation-induced martensite (ferrimagnetic phase) on stress corrosion cracking of 1Crl8Ni9Ti stainless steel was investigated. Low temperature (-70℃) elongation method was used to obtain specimens with various martensite contents. SSRT was applied to investigate SCC susceptibility. Fracture morphology was observed with SEM. The results showed that when the content of ferrimagnetic phase was less than 5% or in the range of 16-25%, the SCC susceptibility of the material decresed with the increasing ferrimagnetic phase content. However, when the content of ferrimagnetic phase was in the range of 5-16% or more than 25%, its SCC susceptibility increased with the increasing ferrimagnetic phase content.

The passive films on Fe-Cr, Fe-Al, Fe-Cr-Al and Fe-Mn-Al-Cr alloys were studied by anodic polarization curve measurements in 0.5mol/L H2SO4 and by XPS analysis. It was shown that Al and Cr are enriched at the surface for all these films. The enrichment factor of chromium at the film surface, ηCr, for Fe-5Cr alloy was 3.7, and 2.22 for Fe-5Cr-3Al alloy. The 90 for Fe-26Mn-3Al-6Cr alloy was 3.53, which implied that under this condition aluminium did not suppress the enrichment of chromium. The passive film on Fe-Mn-Al-Cr alloy was superior to that on Fe-Cr alloy and was much better than that on Fe-Cr-Al alloy with the same contents of Cr and Al.