The kinetic behavior of growth of metastable pits on amorphous NiCrFeSiB alloy in NaCl solution was studied using the potentiostatic polarization method. The growth current of metastable pits increased according to the formula I-I0=k(t-t0)2, with the parameter k valeus representing growth rates of metastable pits following lognormal distribution. As potential increased, both the average k and maximum k values increased remarkably. The peak currents for metastable pits also follow lognormal distribution and rise with potential. A two stage growth process for metastable pits was suggested.

Electrochemical performance of AZ41 magnesium alloy sacrificial anode in saturated calcium sulfate-magnesium hydroxide solution was investigated over the temperature range from 20℃ to 80℃ by galvano-static polarization technique. The potential, current efficiency and surface morphology of the anode after corrosion were not significantly affected by temperature. Current density did not alter current efficiency, while higher current density shifted the potential towards noble and altered corrosion morphology. At various temperatures AZ41 anode was always in the active state and passivation was not observed. XRD showed that the only corrosion product on anode surface was Mg(OH)2. These results gave helpful hints for application of the anode at elevated temperatures.

The chemical reaction processes occurring during the curing of epoxy powder coating and the phenolic modified epoxy coating were investigated. The structures of these two coatings were also studied and the effect of crosslinked structure on water absorption of coatings was examined by the static immersion testing in distilled water at 90℃. The results showed that the curing reactions of phenolic modified epoxy coating consisted the reaction between epoxy and curing agent, the copolymerization between phenolic resin and epoxy, as well as the polymerization of phenolic, while the curing process of epoxy coating only consisted of the crosslinking between epoxy and dicyandiamide. The cross-linked density in the mixture structure of epoxy and phenolic resins increased because of the crosslinking between the two resins. The resistance of this coating to medium permeation was enhanced. The curing time of phenolic resin modified coating should be properly extended at high temperature so that the curing reaction could be conducted thoroughly and the more ideal structure of coating for enhanced permeation resistance could be obtained.

The SCC behavior of Alloy 800 in boiling 50%NaOH solution containing 0.3% SO2 and 0.3%Na2S2O3 was studied using C-ring specimens at controlled potentials. A discussion was given based on the results of SCC tests, anodic polarization curves and AES analyses. Alloy 800 exhibited high susceptibility to caustic SCC in the passive region at potentials more noble than ca. -0.30V (SCE) and was much less susceptible to SCC at potentials more active than ca. -0.45V (SCE). The difference in SCC susceptibility was associated with the composition of surface films formed in different potential ranges. The surface film formed at higher potentials consisted of oxides of Ni in predomination with some Fe and little Cr, while that formed at lower potentials was composed of oxides of Cr, Ni and Fe. The latter showed much higher resistance to caustic SCC.

The mutual influence between deformation and anodic dissolution of AISI 321 austenitic stainless steel in an acidic chloride solution was studied. The corrosion rate of the steel increased remarkably due to the deformation-accelerated anodic and cathodic processes. The creep rate was increased while the yield strength was reduced by anodic dissolution. The analysis by thermal activation theory of deformation showed a linear relationship between the logrithm of creep rate and the logrithm of anodic current. Besides, the reciprocal of yield strength was also linearly dependent on the logrithm of anodic current. These findings were in good agreement with experimental results.

Polarization curves of Fe/H2SO4, Fe/H2SO4+Na2SO4, Fe/H2SO4+Fe2(SO4)3 and Fe/H2SO4+NaCl systems in the presence of magnetic field or/and inhibitor were measured. Experiments showed that the predominant control of corrosion was the cathodic process and the polarization curves of Fe/H2SO4+Na2SO4 system were nearly the same as those of Fe/H2SO4 system. The individual and combined effects of magnetic field, inhibitor, Cl- and Fe3+ on the cathodic and anodic polarization behavior of Fe/H2SO4 systems were investigated. Formulae for overall current density of hydrogen evolution at cathode of abovementioned systems in the presence of magnetic field and inhibitor were suggested.

The electrochemical states and cathodic polarization behavior of Fe/xH2SO4+y/K2Cr2O7 systems (x=0.1- 2 mol/L, y/=0.01-0.4 mol/L) were investigated. The electrochemical states of iron in relation to [H2SO4], [K2Cr2O7] and [H2SO4]/[K2Cr2O7] ratio were established, including active state, passive state and metastable state. Five types of cathodic polarization curve were analysed and the effect of magnetic field (0.4T) on the cathodic process was discussed.

By means of AES and XPS surface analyses, the alloying element distribution, composition and structure of surface passive film of stainless steel OCrl8Nil5Mo4 were investigated in 20%H2SO4 solution and 20%H2SO4+35g/L Cu2+, which simulated the solution in wet process of copper extraction. The results showed that the passive films possessed duplex structure consisting of an outer hydroxide and an inner oxide. The passive film in reductive dilute sulphuric acid was found to be enriched with Mo (VI), N and Cr3+. The passivation effect of Mo in passive film might be reduced with the depolarization effect ' due to Cu2+ ions added.

An investigation of the corroison prevention performance of epoxy coating containing aluminum polyphosphate was conducted using electrochemical impedance spectroscopy (EIS). When the weight percentage of aluminum polyphosphate in coating reached 20%, the epoxy coating exhibited the best performance, and the mechanism of the active anti-rust pigment was discussed. For the study of paint formulation EIS presented consistent conclusions with those from seawater immersion testing. The complicated time dependence of EIS plots indicated that the corrosion control step of metal under coating changed from diffusion controlled step to electrochemical reaction controlled step.

Multiple Small-angle-cone-specimen Test (MST) was proposed for the investigation of corrosion fatigue crack growth. Corrosion fatigue of H68 brass in Mattsson solution was examined to illustrate the experimental procedure as well as results of the new method. Comparing with CT, CCT, WOL specimens and replica method, the new method showed several advantages: (1) Growth behavior of multitude surface cracks on different transverse sections can be examined simultaneously; (2) Both electrochemical environment and mechanical condition can be maintained during the test without disturbance; (3) It is convenient to study the relationship between crack growth path and micro-structure; (4) The experimental equipment required is easy to get. Both time and expenses can be saved for measurements.

Gauss-Newton method was used to estimate the values of electrochemical kinetics parameters by fitting the weak polarization curve of the corroding metal. In this paper, two new computation programs based on optimum step Gauss-Newton method and Levenberg-Marquardt method were proposed to speed up the fitting convergency and relax the requirements for initial values. The fitting results computed by the two improved methods were in good agreement,which indicated that both methods were applicable to the three and four parameters polarization curve equations.

Hot corrosion behavior of TiAl intermetallics in (Na,K)2SO4 and in Na2SO4+NaCl melts was investigated respectively. TiAl showed good hot corrosion resistance in (Na,K)2SO4 melts at 900℃ due to the formation of a barrier layer of Al2O3. However, TiAl suffered from severe hot corrosion in Na2SO4+NaCl melts at 850℃, where the protective Al2O3 barrier could not form. The mechanism of hot corrosion of TiAl was briefly discussed.

The anodic polarization curves of stainless steel CIS in aqueous solution of 20wt% H2SO4 were measured under superimposition of a range of alternating current from 0mA/cm2 to 20mA/cm2. It was found that the presence of A.C. altered the corrosion potential, enhanced the active-passive peak, increased the dissolution current density in the passive region and shifted the passive-transpassive potential towards the negative direction. When the alternating current density was not more than 20mA/cm2, a wide passivation region remained.