The corrosion of carbon steel in 3.5% NaCl solution under laminar condition was studied by combination of numerical method with experimental measureent. The results showed that the hydrodynamic parameters close to the material surface (shear stress τ,ass transfer coefficient κ)can describe more accurately the effect of flowing fluid on corrosion of material than those in bulk solution(flow velocity υ).Numeration and analysis were carried out on the basis of a mathematical model for flow-induced corrosion occured in rotating disk apparatus.It was found that the corrosion rate obtained from numerical method was almost equal to the measured corrosion rate,and that the corrosion mechanism of carbon steel in flowing single phase solution was further verified by numerical results.

Introducing turbulent flow theory,the corrosion of carbon steel in 3.5% NaCl solution under turbulent condition was studied by combination of numerical method with experimental measurement.The mathematical model for flow-induced corrosion in rotating disk apparatus was established by applying wall function and κ～ε equations,and on the basis of the model the numeration and analysis were carried out.The results showed that the numerical corrosion rate was almostly equal to the measured corrosion rate.Thus it was verified that electrochemical action still played an important role in corrosion of carbon steel under trubulent condition.The critical hydrodynamic parameters were very significant in clarifying accurately flow-induced corrosion.

The adsorption and desorption behavior of three kinds of organic corrosion inhibitors {β-phenylamino-propiophenone(PAP),hexadecylpridinum bromide (HDPB),and cetyltrimethyl ammonium bromide (CTAB)} and /or Ⅰ- on iron electrode in 0.5mol·L-1H2SO4 solution was investigated by polarization curve measurements.The results showed that the adsorption stability of the organic inhibitors and/ or Ⅰ- was closely related to their anodic desorption behavior.The anodic desorption potential (Edes)of the joint adsorption layer was more stable.The dependence of Edes on the concentration of each constituent not only could provide an evidence for the joint adsorption mode but also could decide the competitive ability of the different species.Furthermore,The desorption rate and the desorption potential region of various sdsorption layers were discussed on the basis of the differential polarization curves.

The influence of Cl-,SO42-,PO43- and Cro42- anions on the nucleation,growth and repassivation rates of metastable pitting of an amorphous alloy was studied using potentiostatic polarization method.During the repassivation period of metastable pits,the relation between current and time followed Imax I=R(t-tmax),with the repassivation rate parameter R following a lognormal distribution.Increased Cl- concentration resulted in faster nucleation and growth rates for metastable pits.The presence of SO42-,PO43- and CrO42- anions decreased both the nucleation rate and the growth rate of metastable pits.The inhibitive effects of these three anions on nucleation and growth of metastable pits decrease in the order:CrO42->PO43->SO42-.The anions affected the R values only in a very small extent.

To understand the application of copper for anti-fouling the dissolution mechanism of copper was investigated in 3% NaCl solution by means of potentiodynamic polarization and electrochemical impedance spectroscopy as well as cyclic voltammetry.Copper in active region dissolved in the form of CuCl2- complex,and the rate of dissolution was controlled by its diffusion from the copper surface to the bulk of the solution.The kinetics mechanism of copper dissolution in active region was suggested.The galvanostatic experiments showed that copper was electrolyxed and than transferred to the surface to be protected against fouling in the form of cuprous species,and that the divergent reaction of cuprous ions to cupric ions had not been found.

The approach of neural networks was made on its applications to the correlation between molecular electronic structrue and corrosion inhibition properties of aniline and its halogenated and methylated derivatives with substituents at different positions.It was found by reference [2] that there exists the relation between the inhibitive efficiency of the above compounds in acid media for mild steel and their electronic structures;and a tentative interpretation was given for the phenomenon that when the inhibitiors are substituted with the same kind of substituents at different positions in the molecule,or with different substituents at same position,they exhibit different inhibitive effciency.The mechanism of corrosion inhibition was also wxplained from the point of view of electron transfer and the information provided in that paper could be probably useful for developing new more effective inhibitors.The present authors believe that the molecules of the inhibitors were possibly adsorbed on the surface of iron electrode in horizontal state.The inputs of neural networks included the molecular structure parameters,such as hydrophobic index (π,π-),molar refraction (MR),steric parameter (Es),electronic index (σ,σ*),as well as net charge and πcharge of N atom (qN),and low-unoccupied molecular orbital(LUMO),which could be calculated by means of semi-empirical methods of quantum chemisty,including HMO and CNDO/2 methods.The neural network's outputs were the corrosion-inhibiting efficiencies of aniline and its halogenated and methylated derivatives for mild steel in acid media.The corresponding relationship and modelling prediction were established by using neural networks with 8-15-1 topological structures trained by a modified backpropagation (MBP) algorithm,respectively.The learning precision was high and the predicting performance was excellent.The corrosion inhibiting properties or electrode parameters of some new aniline's derivatives were predicted quantitatively and the results were quite good.

The oxidation of NiAl,NiAl-20Fe and NiAl-30Fe at 1000～1100℃ in air has been studied.Fe addition changes single βphase sturcture of NiAl into two phase structure (β and γ).Pure NiAl shows excellent oxidation resistance due to the formation of an Al2O3 scale.NiAl-20Fe also shows good oxidation resistance due to the formation of an Al2O3 scale on β phase substrate.Besides,some nodules consistion of mixed oxides of Fe and Ni grow over ductile γ phase substrate.Besides,some nodules consisting of mixed oxides of Fe and Ni grow over ductile γ phase incorporated in the β phase substrate.NiAl-30Fe alloy suffers form catastrophic oxidation due to the formation of a non-protective Fe and Ni-rich scale,Which is extremely susceptive to spallation.Therefore,the two phase sructure of NiAl-Fe is detrimental to its oxidation resistance.

Isothermal and cyclic oxidation behavior of Co-40Cr(wt%) alloyin air at 1000℃ was evaluated.SEM/EDXA was used to examine the scale formed on the alloy.By comparing the different oxidation behavior of Co-40Cr alloys which were implanted with 3×10 16Y+ and 3×10 17Y+/cm2 or unimplanted,it was found that only Cr2O3 scale was ormed on all alloys with and without implanted yttrium,but the oxidation resistance of the alloy was greatly inproved by yttrium implantation.SIMS method was also used to examine the yttrium concentration depth profile.The main reason for the improvement os that yttrium can segregate at Cr2O3 grain boundaries,This may change the scale growth mechanism rom predominant Cr3+ cation outward diffusion to predominant O2- anion inward diffusion, and greatly decrrase the diffusion rate.In the mean time,yttrium implantation inhibited the formation of "Kirkendall"holes at the scale / alloy interface,thus remarkabl enhanced the adhesion of the scale formed on yttium-implanted Co-40Cr alloy.

Acoustic emission (AE)and SEM/EDXS were used to study the cracking and spalling behavior of the scale formed on Co-40Cr aloy after 20h isothermal oxidation in air at 1000℃.By comparing the cracking and spalling behavior of scale formed on 3×10 16Y+/cm2 and 3×10 17Y+/cm2 implanted and non-implanted Co-40Cr alloys, it was found that yttruim implantation greatly improved the anti-cracking and anti-spalling properties of the scale.AE was used to study the distribution of pre-existing defects at the scale/ alloy interface.The improvement of adhesion of the scale formed on yttrium-implanted aloy was attributed to the decrease in the size and number of pre-existing defects at the scale/ alloy interface

The effects of sulphate and temperature on the corrosion behavior of rebar in simulated pore solutions were studied by potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The results showed that in the presence of chloride ions in simulated pore solution,sulphate ions had inhibition action,which enhanced the corrosion resistance of rebar.The inhibition mechanism of sulphate could be explained by the xompetitive adsorption between sulphate ions and chloride ions on the rebar surface.The polarization resistance(Rp) decreased with the ncrease in temperature and the decrease in pH.Meanwhile,the activation energy of corrosion reaction of rebar was calculated.With the elevation of the pH value from 9.75 to 12.45, the activation energy increased from 43.44 to 62.44kJ/mol.K.

The object-oriented method was used to analyze and design this database,BMP file was used to store images and bivariate table structure of related-database was used to store data.The management system and the user's interface were programmed with Borland C++ language.Thus a metal corrosion image database expressed in chinese was established.The database contained 113 isocorrosion diagrams for 39 metallic materials in 22 corrosive media and 83 E-pH diagrams for 35 metals in aqueous solutions.There were several ways of inquiry and library maintenance.By using plot interface,the supporting environment of the datavase system was simple.and the manipulation was convenient.The only operation was selection of the items in the menus,without inputing any character.