Two Ni-Ag alloys, containing Ni of 50 at% and 75 at %, denoted as Ni-50Ag and Ni-25Ag were consolidated with hot pressing (HP) proce ssing after mechanical alloying (MA) for 80 hr. The nanocrystalline alloys have been oxidized in air at 600-700 ℃ for 24 hr.Ni-50Ag alloy undergoes an inte rna l oxidation of nickel associated with the formation of a continuous outermost la yer of silver metal and has oxidation rates larger than those of pure nickel. On the contrary, Ni-25Ag alloy forms a continuous NiO layer surmounted by a discon tinuous silver layer, while the internal oxidation is suppressed. These results are interpreted on the basis of the two-phase nature of the alloys and of their particularly small grain size.

Four low carbon steels with different metallurgy factors have been se lected.Their susceptibility to pitting has been compared by means of polariza tion test.Characteristic of pitting initiated by different inclusions has been studied with the EPMA and the dissolving production has been confirmed with the MCT during pitting initiation.The results showed that the susceptibility of boi ling steel to pitting initiation was markedly lower than those of killed steel , the pitting susceptibility of killed steel treated by rare earth was between bo iling steel and common killed steel.The inclusions were the sites most suscepti ble to pitting initiation.Passivation film of boundary between steel matrix and inclusions was the weakest and the early pitting corrosion was caused from here .The difference of susceptibility to pitting initiated by homogeneous inclusion s was large when these inclusions existed in different kind of steels.The diffe rence of susceptibility to pitting initiated by different inclusions in the one steel was small and the sulfide inclusions had bigger ability of initiating pitt ing than other types of inclusions did.

Ion-selective (anion-selective,cation-selective and bipolar) phenolic coatings were prepared by mixing phenolic varnish with ion ex changers.SO2-4-type anion exchanger resin and Na+-type cation exchange r resin were utilized as anion and cation exchangers respectively.The bipolar co ating consisted of an anion-selective inner layer and a cation-selective outer l ayer.The corrosion compositions of carbon steel depriving of the painted ion-sel ective coatings after exposure in 3%NaCl solution for 30 days were investigated by XPS.The research results of XPS showed that the main compositions in the surf ace layer of carbon steel are Fe2+,OH-,O2- and Cl-under SO2- 4-type anion-selective coating,whereas the main compositions are Fe2+, Fe0,OH-,and O2- under Na+-type cation-selective and SO2-4-ty pe anion-selective / Na+-type cation-selective bipolar coatings.The XPS signal o f Cl-can be inspected obviously on the surface layer of carbon steel with anio n-selective coating,whereas there is no obvious signal in the case of cation-sel ective and bipolar coatings.This indicated that Cl- could migrate from the NaC l solution to the substrate metal when carbon steel covered with anion-selective coating,whereas the migration of Cl- would be blocked in the case of cation-se l ective and bipolar coatings.From these results,it can be concluded that SO2- 4-type anion-selective coating has poor corrosion resistance,Na+-type cati on-selective coating has better corrosion resistance,and SO2-4-type anio n-selective/Na+-type cation-selective bipolar coating has excellent corrosion resistance.

A new formula containing H3PO3 as phosphorus so urce of Zn-Fe-P electrodeposits was reported.The results showed that the content s of the phosphorus and the iron in the electrodeposits change synchronously.The electrochemical behavior of H3PO3 and Fe2+ in the electroplating solu tion has been investigated by cyclic voltammetry, it was shown that they promote s the reduction of each other and which has been studied in the view of quantum chemistry firstly.The theoretical results showed that, because the orbit radius of 4s of Fe is shorter than that of Zn, the overlapping integral of iron and pho sphorus(sFe-P) is smaller than that of zinc and phosphorus(sZn-P) wh ich results in the synchronous variation of the contents of the phosphorus and t he iron in the electrodeposits, and which also showed that the cooperative effec t of phosphorus and iron series metal.

The effect of corrosion on cavitation erosion on 20 SiMn in single liquid (distilled water) and liquid-solid two-phase medium (silic a sand-containing distilled water) was investigated by using ultrasonic vibratio n facility. The mediums were added with 3% NaCl in order to study the effect of corrosion factor on cavitation erosion. The degradation mechanism was analyzed b y SEM observation and profile measurement. The results showed that there was synergistic interaction among electrochemical corrosion, solid particle eros ion and cavitation erosion. The surface profile of the material gets smoother in liquid-solid two-phase medium than in single liquid after cavitation erosion. C orrosion has remarkable influences on cavitation erosion of 20SiMn in both singl e liquid and liquid-solid two-phase medium. And the cavitation erosion comparati ve enhancement by corrosion in two-phase medium was less than that in single liq uid medium.The phenomenon was explained by morphology and profile observation.

Fluxing in aqueous solution containing passivator a nd hot-dipping techniques were employed to prepare 55%Al-Zn alloy coating on car bon steel Q235.Effect of temperature，H2S content，NaCl concentration，pH valu e and immersion time on corrosion behavior of hot-dip 55%Al-Zn alloy coating in H2S-NaCl-H2O system were studied.Surface morphology of this coating before a nd after corrosion was observed.The corrosion mechanism of 55%Al-Zn alloy coatin g in H2S-NaCl-H2O system was illuminated.Results showed that 55%Al-Zn alloy coating had the same ability as galvanized coating to protect the steel，and was 2～3 times corrosion resistant than galvanized coating ,10～11 times corrosion resistant than carbon steel Q235.

Corrosion of carbon steel and the weathering steel in marine atmosphere during different time was compared,the morphology of rust layer was observed,and the distribution of the alloy elements in the rus t layer was determined.The results show that corrosion rust of weathering steel exposed in the atmosphere for 1 year consisted of inner layer and outer layer ob viously, the former is composed of α-FeOOH mainly,and the latter is of α-FeO OH and a little FeO.There are some cracks distributed in the inner layer,where contains richer alloy elements compared to the substrate steel.

Although dewing is well recognized to play an impor tant role in the atmospheric corrosion of metals, direct observation of dewing p rocess has not been reported. In order to demonstrate the phenomenon in laborato ry, a simple experimental arrangement was set up. Since dewing is a result of mo isture condensation when metal surface is chilled down below the dew-point tempe rature of the air, a semiconductor cooling unit was adopted to cool the plate sp ecimen. Thus dewing process could be observed under metalloscope, and photograph s of the dew droplets could be taken when necessary. Initially minute droplets appeared upon cool surface. Then adjoining drops merged into a larger one and so drops grew gradually. Finally a thin water film covered entirely the specimen s urface. In this way various influencing factors could be examined with ease. Wh en the specimen surface was covered with dust, dewing took place surrounding the dust with priority. On the salt contaminated surface dewing was much easier. Th ese illustrated unambiguously the enhanced effect of dust and salt contaminated on atmospheric corrosion.

Corrosion database based on WWW(world wide web) and its data querying system which uses ASP(ActiveX Server Pages) technology are introduced, It can accelerate the querying of corrosion data and extend the use of corrosion data.The designing and achieving process of corrosion database que rying system was also discussed.

The evolutional mechanisms and the categories of electrochemical noise (EN) and the more fascinating properties of EN technique versus other traditional electro c hemical methods were reviewed in this paper. Meanwhile, the experimental methods and some problems which might arise in experiments and especially the analysis techniques (such as time-domain analysis, frequency-domain analysis, wavelets an alysis and some other analytical methods based on EN method) of EN were discusse d, and the advantages and the disadvantages of each EN analysis methods were com pared too. According to the problems existed in the current analysis and applica tion of EN, the development of EN technique in the future was forecasted.