The corrosion behaviors of mild steel in simulated solutions within pits and crevices were investigated by polarization measurement s an d EIS.The results showed that the cathodic process was controlled by the diffusi on of hydrogen ion at pH 2～4,and controlled by electrochemical process at pH lo wer than 2.The anodic dissolution took place by Bockris mechanism.A critical pH value or salt concentration was not observed for mild steel.The logarithm of cor rosion rate was inversely proportional to the pH value.A small change in pH valu e within pits/crevices would result in a marked change in corrosion rate. The en richment of Cl- anions within pits/crevices would cause a decrease in pH value .

Cold working induced martensite content on type 304 stainless steel equipment was examined on-site.With different modes and differe nt degree of cold working at room temperature,the martensite content was about 0 . 5%～10%.By potentiodynamic polarization,galvanostatic polarization and simulated occluded corrosion cell methods,the relationship between pitting potential(E b),pitting initiation potential(Enp),corrosion potential(E corr) and martensite content on 304 stainless steel which had been prepared by low temperature(70℃) tensile deformation was investigated in 3.5%NaCl solut ion.Experimental result showed that when the martensite content was between 0.1% (the material without low temperature tensile deformation) and 11.5%(the mate rial with 10% low temperature tensile deformation),with the increas ing of martensite content the potential of Eb,Enp and Ec orr changed negative(when then martensite content is 5%,the potentials were th e most negative),the pH value in occluded cell dropped and the current density i ncreased.It meant that cold working not only accelerated pitting initiation,but also accelerated pitting propagation of 304 stainless steel.

The effects of PO3-4,CrO2-4,SO2 -4and NO-3 anions on the nucleation and growth of metastable pitting of 316L stainless steel in NaCl solutions were investigated using potentiostatic an d potentiodynamic polarization tests.The four anions all retard nucleation and t he growth of metastable pitting.PO3-4 ions show the strongest inhibition on metastable pitting,followed by CrO2-4 ion,and SO2-4,and NO- 3 ions have less inhibition effect.Both metastable pitting potential Em and stable pitting potential Ep increase almost linearly with logarithm of each anion concentration,and have very close increasing slopes.The inhibition m echanisms of the four anions were also discussed in this paper.

In situ measurement of corrosion rate of mild steel and soil factors has been carried out in Shenyang soil site.It showed that soil conductivity and soil salt content ，corrosion rate of mild steel increased wit h the raising of soil temperature.At the time of alternate spring and summer (f rom April to July),on account of underground temperature and soil conductance ri sing acutely,corrosion rate of mild steel was the highest.The error of copper be tween the in-situ corrosion and soil natural corrosion was not high,and the erro r reduced gradually with the extension of the test period.Therefore,the instrume nt of soil corrosion can measure quickly the corrosion rate of mild steel in-sit u.

Corrosion results of 5 types of stainless steels ex posed to splash zone at Qingdao Sea area of China were obtained.Corrosion behavi or and law of stainless steels in splash zone were summarized.2Cr13 could not ke ep passive state in splash zone.Its corrosion resistance was poor.Stainless stee ls containing more than 16% Cr shown good corrosion resistant in splash zone,and their maximum pitting depths at Qingdao Sea area for 16 years exposure were les s than 025mm.It was found that pitting rate is big for 1Cr18Ni9Ti,00Cr19Ni10,0 00 Cr18Mo2 during the 2 to 4 years and for F179 during 1,2 years,after which the pi tting depth deepened not obviously with exposure time.Pit density of stainless s teels in splash zone increased with exposure time.Crevice corrosion of stainless steels in splash zone formed and grew more easily than pitting corrosion.Increas ing Cr content and adding Mo enhanced corrosion resistance in stainless steels i n splash zone.Corrosion behavior of stainless steels in splash zone was similar t o their corrosion behavior in marine atmosphere.Stainless steels in splash zone corroded seriously than ones in marine atmosphere.

Some quantum chemical parameters of triphenylphosph ine,tetraphenylphosphonium chloride,chlormethyltriphenylphosphonium chloride and benzyltriphenylphosphonium were obtained by means of PM3 semi-empirical quantum chemical calculation method of MOPAC 6.0 programs package.It is found that the rates of these corrosion inhibitors have a certain relation to the electron dens ity of phosphorus atom of molecular and π electron on aromatic ring.The possibl e mechanism of inhibition was also been discussed building on the interaction be tween ion and inhibitors.

Chlorosulphonated polyethylene(CSM)modified HCPE ant icorrosive coating was studied in this paper,and the microstructure and its infl uence on p roperties were characterized by TEM test.Results indicate that HCPE particles we re embedded in the dispersed phase of CSM,which can modify flexibility of paint f ilm.Meantime,it is good for keeping excellent adhesivity and rigidity of HCPE wi th low content of CSM in this coating.Besides,the flexibility of CSM modified H CPE anticorrosion paint is superior to clorafin modified HCPE.

The oxidation behavior of Ni20Cr(mass%) and some pr e-oxidized Ni20Cr with the Ce+ implantation is studied.The results indicate th at the effect of the Ce+ implantation after 0.5 and 1 hour pre-oxidation treat ment on the oxidation behavior is similar to the effect of direct implantation,w hich can decrease the oxidation rate and improve the adherence of surface oxide film,but the degree of effect is different.The results are explained accord ing to the current REE mechanism.

Corrosion behavior of as-cast ADC12 aluminum alloy and ADC12 aluminum alloy after solution heat treatment in aqueous vapor at 94℃ was studied.The results show that for as-cast aluminum alloy,the corrosion of al uminum alloy matrix is caused by the Al-Cu second-phase compound.For aluminum al loy after solution heat treatment,the corrosion of aluminum alloy is caused by t he Al-Fe compound,furthermore,the matrix around the phase pasticles containing m ore Cu is prior to be corroded.

The theoretical calculation and XPS analysis show t hat the fluoride layer formed during activation in hydrogen fluoride acid dissol ves little in electroless plating bath.The adhesive characteristics of nickel co ating with the magnesium alloys matrix were studied by means of the analysis of the initially deposited nickel and the cross section of the coating as well as t he fracture surface by using TEM,XPS,SAM.It is shown that there exists a mixture co mpound layer above the matrix surface between the magnesium and the nickel coati ng,which consists of fluoride,nickel and the composition of plating bath.Fractur e usually occurs in the mixture layer which is the weakest link for the adhesion of nickel coating on the magnesium alloys.

The inhibiting efficiency of 2-n-undecylimidazole(U DIM)for copper in 3%NaCl solution was investigated by electrochemical impedance s pectroscopy technique and potentiostatic polarization method.The results show th at UDIM suppress both cathodic and anodic corrosion reaction of copper.A remarka ble decrease in the protective effects of UDIM was observed because of the aggre gate formed by UDIM with the increasing of concentration.A new absorption with λmax=214 nm,which attribute to the adsorption of UDIM aggregates,was detected by UV-Visible Spectroscopy.

Development and application status of electroch emic al noise technology in material corrosion and protection,battery,electrodepositi on and bio-electrochemistry were summarized.The newly achievements and the unsol ved problems of electrochemical noise technology when using in material corrosio n and protection,especially in local corrosion were reviewed in detail.The futur e of the application of electrochemical noise technology in industrial electroch emistry was forecasted.

Underfilm corrosion of metals and failure of or gani c coatings in atmosphere are of great interesting and practical meaning.Weatheri ng and underfilm corrosion are the two most important factors which cause failur e of organic coatings.The mechanism of weathering is generally considered to be radical reaction initiated by photon while the mechanism of underfilm corrosion, to be electrochemical reaction.The factors affecting the corrosion and failure i nclude property of the coating,air pollutant,contamination of soluble salts on m etal substrate,surface condition and treating of substrate,and so on.The researc hing approaches are mainly electrochemical methods including DC and AC methods,a nd spectroscopy.Of the electrochemical methods,the electrochemical impedance spe ctroscopy (EIS) is the most important and widely used,and the Kelvin scanning pr obe is a new and promising method.Spectroscopy includes infrared spectroscopy an d Raman spectroscopy.Nowadays it is common to use these methods coordinately and to carry out in situ on-line measurements.The present paper reviews the above a spects.