Simulated occluded corrosion cell(OCC) was used to stud y the changes of chemical state within the OCC of 304 stainless steel in neutra l solution of 0.5 mol/L NaCl containing various SDS(sodium dodecyl sulphate) ion concentration at 50℃.Anodic polarizing occluded specimen to simulate reaction current between outer and inter of OCC.It was found that,when C12H25 SO-4 anion added into the bulk solution,it migrated into OCC,and the migrati on quantity increased with the concentration and the time,the migration rate dec reased with the length of the time.C12H25SO-4 was in competition with Cl- on migration,It can retard the migration of Cl- effectively above a certain concentration,The higher the concentration,the more the efficiency.C 12H25SO-4 can not retard pH fall but fell multiples of Cl- enric hment effectively above a certain concentration.SDS was anioning inhibitor,E b and Ep were shifted towards positive potentials by the addition of C 12H25SO-4,indicating suppression of pit propagation.

According to Ohm's law and Kirchhoff's current law, a differential equation,which related the potential gradient along the width of the spiral plate cooler to the current density at the surface of spiral plate,wa s deduced.By means of a spiral cathode,assuming the spiral plate was passivated, the equation for the potential distribution along the width of spiral was also f ounded.After measuring the specific resistance of concentrated sulphuric acid an d the passive current density of stainless steel in the acid,the potential drop can be calculated.The calculated result was verified by simulated experiments.An industrial cooler was designed according to the present study.After application in situ,it shows the satisfactory anti-corrosive capacity.

In accordance with the criteria to avoid SSC provid ed by European Federation of Corrosion (EFC),the constant tensile load testing a nd three-point bend testing for low alloy and high strength steel WH610D2 were carried out and an acceptable environment of H2S-containing 100×10-6 so lution was identified.To verify the validity of the EFC criteria,a series of wel ded plate testing simulating the anticipated field conditions of pressure vessel s was conducted and the results show that the EFC criteria can be used well in s ervices.The testing plate used includes both welded state and heat-treated state .The working stresses were produced by loading with bolts.The welding residual s tresses and working stresses were measured by PSM-2F X-ray analyzer.Three sets of testing plate were conducted respectively in three different H2S content so lutions:1500×10-6,500×10-6,100×10-6.Upon termination of exp osure after one and two months,the testing plates were examined to determine whe ther cracks occurred.The examinations showed that,on the plates in the solution s of H2S content being 1500 ×10-6 and 500×10-6,many cracks occur red; and on the plate in the solution of H2S content being 100×10-6,no crack was examined.So the results show that the EFC criteria can be used well in services.

While simulating the environment of CO2 co rrosion in oilfield,XRD，EDS and SEM techniques were adopted to study the formation and development of CO2 corrosion product film on N80 steel.The results demonstrat ed that the corrosion scales could protect matrix of N80 steel and the n reduce the corrosion rate.There were three layers in CO2 corrosion product f ilm.Structural characteristics and formation mechanism of the film were discusse d respectively.At the same time,breakage of FeCO3 scale was studied.The CO2 corrosion scale was (Fe，Ca)CO3.〖JP〗

The relationship between molecular structure of imi dazoline derivatives and inhibition performance was investigated by weight loss me thod，potentiodynamic polarization curve and electrochemical impedance spectrosc opy (EIS) in H2S solutions.Result show that the side chains，which occupies 1 or 2 sites on the central five membered ring and has hydrophobic or hydrophilic properties，and some active functional groups have an important effect on the in hibition performance of imidazoline derivatives.Compounds studied have the best in hibitive efficiency when the hydrophobic side chain contains either seven or sev enteen carbon atoms，and the best inhibitive efficiency when the hydrophilic sid e chain contains two aminoethylenes.The double bond in the hydrophobic side cha in and the thiourea group in the hydrophilic side chain can effectively enhance inhibitive performance，nor can the hydroxyl group in the hydrophobic chain.Alth ough the inhibitive performance of imidazoline derivates can be improved through changing the central imidazoline ring chemistry，they do not suit to use as in hibitor because of the poor solubility.

The influence of vacuum heat treatment on NiCrAlY c oating,which was deposited on a Ni-base superalloy substrate by magnetron sputte ring was investigated.It was shown that the sputtered NiCrAlY coating,which cons isted of a two-phase mixture:γ-Ni and β-NiAl phase,had a homogeneous elemental distribution.After vacuum heat treatment,the sputtered NiCrAlY coating mainly c onsisted of γ′-Ni3Al,β-NiAl,and trace of α-Al2O3 phases and the outerm ost layer of the sputtered NiCrAlY coating riched in Al and depleted in Cr.The s puttered NiCrAlY coating after vacuum heat treatment formed α-Al2O3 much ea rlier and the α-Al2O3 scale had a better adherence to the NiCrAlY coating.T herefore vacuum heat treatment improved the oxidation resistance of sputtered Ni CrAlY coating.

The metastable pitting behavior of 316L stainless s teel with different surface roughness in 0.01 mol/L NaCl solution was studie d us ing potentiostatic and potentiodynamic polarization methods and statistical trea tments.As surface roughness decreased,the nucleation rate of metastable pits dec reased.The peak current of metastable pits also decreased,but the average growth rate of metastable pits showed a slight increase.An openness parameter,w/d, was suggested to characterize the openness of surface grooves,in which w is the width of the groove at the opening and d the depth of the groove.Bigger w/d value means more smooth surface,and it is more difficult for micro-pit t o nucleate.Under certain condition of solution and potential,there is a critical w/d value.Metastable pits may nucleate only on those surfaces whose w/d values are lower than the critical value.As the openness parameter w/d incr eases,the nucleation rate of metastable pits decreases linearly,and both metasta ble pitting potential Em and pitting potential Ep move in the positi ve direction.

The corrosion behavior of 316 stainless steel (316S S) in dilute acetic acid solutions containing fluoride/chloride ions was investi gated by using electrochemical measurement techniques.It was found that 316 coul d be passivated in 0.1 mol/L HAc solution mixed with 0.001 mol/L NaF and 0.001mo l/L NaCl or with 0～0.1 mol/L NaF.The well passivated films had an internal chro mium oxide rich layer and an external iron oxide rich layer.The results revealed that F- could increase corrosion rate slightly for 316SS in 0.1 mol/L HAc sol ution.No pitting corrosion occurred in the various tested solutions.The corrosio n rate of 316SS increased with increasing the temperature of solutions containin g F-/Cl- ions,but 316SS was still in the passive state at 80℃.

The corrosion resistance of magnesium-aluminum allo ys is closely related to the corrosion product film formed on the alloy's surfac e.The morphology and structure of the corrosion product film on pure Mg,Mg-Al  and Mg-Al-RE alloys in the solution containing Cl\+- were examined by the var ious sur face analysis techniques including EMPA,EDS,SEM,TEM,XRD,AES etc.The results indi cated that the elemental aluminum is conducive to the corrosion resistance of al loys,but its beneficial effect is limited and unstable.The RE addition can obvi ously increase the Al concentration in corrosion product film.Also,the distribut i on of Al in corrosion product film of Mg-Al-RE alloys was broadened due to the a dd ition of RE.It indicated that the RE element promoted the formation of protectiv e film containing elemental Al.

The diffusing behavior of water through epoxy coati ngs with different pigment volume concentration(PVC) has been studied by electro chemical impedance spectroscopy(EIS).The corresponding diffusion coefficients we re calculated and the effect of PVC on the diffusing behavior were studied.The e xperiment results showed that,in 0.5 mol/L NaCl solution,the diffusion process o f water through epoxy coatings with different PVC followed the second Fick di ffusion law in the initial period.Within the PVC value concerned(35%～50%),the d iffusion coefficients decreased with increasing PVC.When PVC was less than critical pigment volume concentration(CPVC),the obstruction effect by the pigme nt plates was the main factor influencing the diffusing process of water through epoxy coatings.

Y2O3-CeO2-TZP/NiCoCrAlY　graded coating h as been developed on Ni-base superalloy substrate by low-pressure plasma sprayin g with single torch,and the microstructure,mechanical properties and microstruct ure stability,as well as thermal shock properties and its failure mechanism were investigated by means of optical microscopy,X-ray diffractometer,scanning elect ron microscopy,electron probe microanalyser,and so on.The microscopic structure and the oxidation resistant property as well as the anti-thermal shock property were improved after an amount of lanthanum bearing ferrosilicon was added in the metal constituent.

This paper explains the role of metallic materials grain boundary in high temperature oxidation behaviour of pure metals and alloys in brief.There are three effects concerned of increased metallic materials grain boundary area (e.g.decreased grain size):(1) positive (benefici al) effect,improvement on oxidation resistance of metals,(2) in contradiction,ne gative (deleterious) effect,and (3) dual effect.The influences of parameters of fundamental equation of grain boundary diffusion,such as Tammantem perature and influence of grain size on it， factor of grain shape (q)、fact or of GB segregation (s)、grain boundary angle (θ) on the grain boundar y diffusion were discussed,Finally,the importance of grain boundary acted as hig h velocity diffusivity pathways in the intergranular internal oxidation was intr oduced.

Biofouling is one of the main factors that influenc e metal corrosion in marine environment.Biocorrosion has been receiving more and more attention in recent years.In this paper，some respects of this field such as the structure and function of biofilm，mechanism of microbiologically influen ced corrosion in seawater and corrosion induced by marine foulings(banacles etc. ) were reviewed.Also，according to the present situation of this field in our c ountry，some research topics on marine biocorrosion,including local corrosion in duced by macrofoulings and studying MIC in simulated biofilm environment,were di scussed.

Based on the citation statistics of the whole a rticles published in the “Journal of Chinese Society for Corrosion and Protecti on” during the past five years(1996-2000),we analyzed citation amount ,document typ e,citation language,Chinese and foreign language journals cited high frequently, self-citation rate of journal,rate of the papers supported by foundations,period of half-life of citation,price index and the reflected situations of the pape r and journal.The purpose is to objectively evaluate the journal and provide som e proposals for the future development of this journal.