potential distributions inside a cathodically protected crevice configurated by a top plate and segmented mild steel electrodes were measured in diluted NaCl solutions. The effects of the control potential, solution conductivity and crevice thickness on the potential distribution were studied. The results showed that the potential gradient inside the crevice decreased with elapse of polarization time. In general, the more negative the control potential was and the greater the solution conductivity and crevice thickness were,the more negative the potential inside the crevice was. However, when the control potential was over negative, the cathodic polarization of the steel electrodes in the depth of the crevice might be less than that under a moderate control potential because of hydrogen evolution.

Onthe basis of eight year atmospheric exposure data of steels at seven sites in China, a new tyoe of weathering steel-economical weathering steel was developed. The steel,with a composition of phosphorus 0.035% and copper 0.2%, was produced by Wuhan Iron & Steel Company. In addition to cycling immersion accelerating corrosion tests,4year, 3period atmospheric exposure at seven environmental tyoical sites in China including Beijing , Qingdao, Wuhan, Jiangjin, Guangzhou, Qinghai and Wanning, was carried out. Results showed that corrosion resistance of the steel is better than that of commonmild steel at all these seven places. The effect is more notakle at Qingdao, Jiangjin and Wanning, where are characterized with marine salt pollution acid rain pollution aand humid hot plus marine salt pollution respectively.Cycling immersion accelerating corrosion tests showed the new type steel have more obvious advantage over the common mild steel.

Various corrdination models of organic inhibitors on metal surface covered with oxide film were discussed from the viewpoint of coordination theory .The combined influence bitween inhibitors or between inhibitor and metal ion/ atom were also considered.The proper structure of inhibitor molecules could be designed purposely and their performance could be with the discussed coordination models

In order to make further insight into the mature of passivity,the combination of XPS and SERS was employed to ex-situ and in-situ characterize the chemical composition and structure of electrochemically modified passive film of 18/8 stainless steel.It was evidenced that the electrochemical modification gave rise to dehydration of the passive film.There existed an abundance of CrO3 in the outer layer of passive film ,but no CuO42- was sensed by XPS measurements.The enrichment of Cr apeared throughout the passive film, and the maximum of it did mot locate at the outmost layer.It implied that the preferential solvating hapned during the electrochemical modification.Like the coexistence of Cr2O3 and CrO3 in the barrier layer, the oxides of Fe(Ⅱ) and Fe(Ⅲ) species at the outer ayer played a beneficial role in the formation of non-crystalline passive film.It was revealed that from in-situ SERS and ion selective screen of CrO42- may be formed on the surface, which repulsed the attack of the aggressive ions and strengthened the stability of the electrochemically modified passive film of 18/8 stainless steel.

The erosion-corrosion resistance of some Fe3-Al-based alloys at high temperatures was investigated.Erosion-xorrosion experiments were performed in a horizontal systen through which the high temperature air floww containing highly concentrated SO2 and SiO2 particles was blasted off.The results indicated that Fe3-A;-based alloys had much higher erosion-corrosion resistance than nickel-and cobalt-based alloys at temperature between 600-800℃.SEM observations on the eroded specimens of different alloys revealed that the erosion-corrosion of Fe3Al-based alloys was associated with flake formation.For nickel and cobalt-based alloys,the surface of eroded specimens showed ploughing morphology. Small amount addition of tungsten, molybdenum or niobium to the Fe3Al-based alloys resulted in the further increase in the erosion-corrosion resistance.

A probe for measuring soil corrosivity was developed .It can be used to measure not only corrosion current density and corrosion potential of metals in soil but also a series of soil parameters, including resistivity, oxidation-reduction potential and temperature etc.The corrosion current density vs time curves showed that the corrosion current density finally reached to a steady value with the development of soil corrosion under the condition that moisture content and temperature were unchanged during the test.It was verified by grey relation analysis that there was a good relationship between steady corrosion current density measured by probe and corrosion rate obtained by weight loss.

The effect sol preparation with different catalysts,substrate prtreatment and coatings thickness on corrosion tesistance of sol-gel ceramic coatings was studied.The range of sol viscosity and the withdrawal speed for preparing the necessary ceramic coating thickness which could bring optimum corrosion resistance was also explored.By comparing the acid resistance,pitting resistance and oxidation resistance in different corrosive media with various standard electrochemical and chemical corosion evaluation methods for different assembly samples, including SiO2、ZrO2、TiO2、AlO3、SiO2-TiO2 ceramic coatings on stainless steel substrate, it could be concluded that the contineous and dense ceramic coating on stainless steel prepared with sol-gel dipping withdrawal method could provide effective protection.

Eight-year field exposre xorrosion test results of A3 steel and 3Csteel are reported here.Both the immersed and tidal zone, carbon steel corrosion behavior and creature fouling are compared at Qingdao,Xiamen and Yulin exposure sites.Fouling creature can ratard general corrosion but accelerate localized corrosion rate stable at a certain value for long time. The corrosion process affected by fouling creatures is discussed. Corrosion mechanism might change from oxygen controlled to non-oxygen controlled process.

An equation of corrosion depth vs exposure tie of cabon steel in marine environment was deduced, based in the eight-year in-situ corrosion exposure test of A3 steel and 3C steel in Qingdal, Xiamen and Yulin.Aconcept of environmental corrosion coefficent is introduced to interpret the corrosion depth equation.Experimental data and creature fouling status in the immersed zone are in reasonable correspondence with the equation.

The dealloying mechanism of material in service was discussed on the basis of analyzing the structural morphologies of aluminum bronze tube used in sea water pipe line system.The microstructure and morphologies of aluminum bronze before and after being corroded were examined by optical microscope and SEM.The compositions of corroded aresa were analyzed by EDS and the phases before and after cossosion were determined by XRD.The results revealed that dealuminizationcorrosio was obseived in aluminum bronze tube, and the phenomenon preferentially occurred at the interface of α-phase and metastable β-phase.This set up a path for the selective attack to follow β-phase matrix and eventually penetrated the tube.The α-phase showed a minor tendency to dealiminize.