The relationship between corrosion current density (i_a)and strain rate ((?)) as well as plastic strain (ε_p) was measured for 40CrNiMo steel tempered at moderate temperature in the simulated medium of corrosion fatigue tip by employing Pt-wire and 40CrNiMo steel respectively as auxiliary electrode under various tensile rates. The result of which is shown as following: i_a=K_1·(?)_e~A+K_2·(?)~B[1-exp(-ε_p] The analysis of elasto-plastic finite element to the strain at fatigue crack tip was carried out in order to obtain the relationship of crack growth rate induced by anodic dissolution at crack tip of corrosion fatigue with △K. The result showed that the direct contribution of anodic dissolution at crack tip to the crack growth of corrosion fatigue in 3.5% NaCl aqueous solution was very little for 40CrNiMo steel, the major effect of anodic dissolution was to affect the cathodic process at crack tip which supplies hydrogen atoms for hydrogen induced cracking in the fracture process zone of corrosion fatigue.

Atomic absorption spectroscopy was used to determine the dezincification coefficient of 70/30 brass subjected to slow-strain rate stress corrosion tests in 1 normal aqueous sodium nitrite solution over the potential range from -0.1～+0.1V(SCE). The results showed that extensive dezincification occurred in all the tests but potential had opposite effects on the dezincification coefficient and susceptibility to stress corrosion cracking; an increase in potential accelerated crack velocity but depressed the dezincification coefficient. The effect of increasing sttrain rate on the increase of dezincification coefficient was diminished with increase in potential. Similar tendencies of dezincification coefficient as functions of potential and strain rate were obtained by theoretical calculations based on anodic dinsolution model using available date measured by rapid straining electrode. The indication is that the increase of proportion of copper dissolution in the dissolution ratio of zinc to copper was responsible for the drop of dezincification coefficient, even though the total dissolution rate increased with increasing potential, so was zinc in the brass, to enhance the susceptibility to cracking. The implication of the pressent results relevant to the cracking mechanism is further discussed.

Systematic investigation of the effect of alternating voltage (AV) modulation on the features of the passive film on 321 stainless steel has been carried out by means of ellipsometry, potential step and potentiostatic reduction methods. Results of the investigation show that AV modulation increases the thickness and the resistance against cathodic reductire dissolution of the passive film. The parameters of impedance of the passivated electrode is also changed by the AV modulating passivation. An increase of breakdown potential (E_b) of the passive films can be achieved to some extent under certain AV conditions.

The effect of Ni and Ni-P coatings on the SCC behaviour of stainless steel in boiling 42%MgCl_2 solution and that of mild steel in 100℃, 35%NaOH solution was investigated. A perfect Ni or Ni-P coating prevented these two steels from SCC under the test conditions. In the presence of defects or cracks in the coating, the SCC behaviour of the steels would depend on the potential of the coating. SCC can be effectively controlled by metallic coating when the potential of the selected coating is located in the region in which the base metal is insensitive to SCC.

SCC of mild steel, and 16MnR and 12Cr1MoV low alloy steels in caustic aluminate solution was invesigated by means of the slow strain rate technique The effect of AlO_2 anions on anodic dissolution was also studied It was found that anodic dissoiution of the above mentioned steels was inhibited and that their repassivation rate was reduced in the presence of AlO_2 in NaOH solutions. A dual influence of AlO_2 on stress corrosion behavior of the steels was observed. The addition of AlO_2 tended to shorten the period of time for crack initiation, whereas to retard crack propagation. 12CrlMoV steel exhibited the highest stress corrosion resistance of the three tested steels. All the results can be explained in terms of a combined action of pre-existing active and film-rupture model.

Fractal dimension of different parts of two fracture surfaces created by stress corrosion cracking in a high strength steel has been investigated by means of fracture profile analysis. The results show that the fractal dimension of the fracture surface corresponding to the sub-critical propagtion zone increases as the crack propagates. Therefore the process of stress corrosion cracking is the one during which the fractal dimension of the fracture surface increases.

The initiation, growth, and repassivation of metal/metal crevice corrosion of lCr18NigTi steel in aqueous 0.03%, 0.3%and 3%NaCl solutions were investigated. Laboratory date indicate: (1) There exists a critical potential V_(CREV) for crevice corrosion. When a specimen is polarized to a potential more positive than V_(CREV), crevice corrosion is likely to grow. When polarized to a value more negative than V_(CREV), crevice corrosion can still occur but the specimen soon becomes repassivated. The repassivation potential of the specimen E_R, is a characteristic value depending on the geometry of the crevice configuration. The lower limit of E_R coincides with that of V_(CREV), (2) The initiation of crevice corrosion follows probability statistics. The initiation probability is found to have a stable value under specified conditions. This probability is another characteristic of crevice corrosion and is independcnd of E_R, (3)The growth (development) of crevice corrosion becomes accelerated with rise in temperature and potential but in different ways.

Corrosion resistance of 6Cr13 stainless steel after short time treatment in H_3PO_4 solutions was evaluated in 3.5% NaCl at 25℃ for 4 hrs and the effect of H_3PO_4 concentration in and the addition of Cu~(2+) to the solutions on corrosion resistance were also studied AES and XPS were employed to determine the chemical composition and structure of the surface films formed on the steel. The results indicated that the increase in corrosion resistance of the treated steel was related to the enrichment of Cr in the surface films. The structure of the surface films was dependent upon H_3PO_4 concentration in solutions.

The functions, the architecture and the establishment of Atmospheric Corrosion Database System for Materials (ACDSM) are described in this paper relatonal data structure is used for database design. The system can be used to collect, arrange and store vast amount of atmospheric corrosion data of ferrous and nonferrous materials as well as thoes of coatings in eight different kinds of climate conditions in the whole country, and supply fourteen kinds of forms needed. The advantages of this ACDSM include convenience of operation and easiness to learn to use.

Laser remelting treatment was done on the surface of 2Cr13 stainless steel by 2kW CO_2 laser with continuous wave. The passive characteristics and the stability of passive films of treaed area were determined respectively in 0.5 mol/L H_2SO_4 and 0.5mol/L H_2SO_4+0.3mol/L NaCl by means of potentiostatic-galvanostatic transient technique and other electrochemical measurement methods. The microstructure and surface morphology at laser remelting area were observed by scanning electron microscope (SEM). The results indicated that laser remelting treatment improved the passive performance of 2Cr13 and that its stability and pitting resistance of passive films were promoted a lot. The corrosion characteristic of treated area is comparable to that of 0Cr18Ni9 austenitic stainless steel. The corrosion resistance mechanism was discussed preliminarily.

A systematic investigation was made on the change of potential at pit bottom on aluminium alloy 3003 in neutral chloride solution (3.5%NaCl) with potentiodynamic, galvanodynamic, potentiostatic and galvanostatic measurements. The potential at pit bottom of this metal in the solution is more positive than that on surface. The larger the dissolution current, the more positive the potential at pit bottom is than that on surface. The pit bottom potential is gradually getting negative at constant current.

Pitting behavior of passive AISI 304 stainless steel in 0.25M Na_2SO_4 aqueous solutions of pH1.0 containing chloride has been investigated using electrochemical impedance spectra(EIS). The characteristics of the measured impedance spectra have been analyzed. The following conclusions have been obtained: (1) The inductance occurring in very low frequency range at pit propagation stage and the impedance characteristics at pit initiation stage can be well interpreted by the adsorption-transitional chloride containing complex model (2) Under the experiental conditions, the adsorption of SO_4~(2-) on the surface of pits is the controlling factor for pit propagation kinetics. (3) The variation of the reciprocal of the overall charge transfer resistance of pitting reflects the variation of the overall pitting current.