The 304 austenitic stainless steels with the different doped content of nitrogen (N) and niobium (Nb), have been tested separately using potentiodynamic polarization curve scanning and electrochemical potentiodynamic reactivation method (EPR). The resistance to pitting corrosion of the specimens was evaluated by the pitting potential (E_b), and the reactivation rate reflected the resistance to intergranular corrosion. The experiment results showed that the resistance to pitting corrosion of the 304 austenitic stainless steels has been obviously improved by the rising doped content of N. It was also observed that when there is a little doped content of N, the resistance to intergranular corrosion suffered a negative influence, but with the increasing amount of N(above 0.2%), the bad effect for specimen resistance to intergranular corrosion disappeared. The Nb doping played a positive role in the specimen resistance to intergranular corrosion but a negative role in resistance to pitting corrosion. Based on the results above, a proper doped content of Nb and N was given, and the mechanism of the influence on the anticorrosion performance of the stainless steel caused by the microalloying was discussed.

A small amount of PbO could induce the passive film of alloy 690TT unstable in the caustic solutions at room temperature. The immersion tests were carried out in high temperature lead-containing caustic solutions in a static autoclave. The results showed that alloy 690TT immersed in 10% NaOH+10 g/L PbO solution suffered from intergranular attack (IGA) at 330℃, and the specimens lost weight. The coarser the original surface of the samples, the more serious the samples suffered from corrosion. IGA was observed and developed as intergranular stress corrosion (IGSCC) with respect of residual stress. While no IGA was found for the samples immersed in 10% NaOH solution at 330℃.

In the corrosive solution 0.1 mol/L H₂SO₄+0.25 mol/L Na₂SO₄, the effect of allyl-thiourea (ATU) on the corrosion behaviors of bulk nanocrystalline ingot iron (BNII) was studied. Inhibited by ATU at ambient temperature, for CPII, when immersion time as short as 5 min, an inductive loop appeared at different concentrations at the Nyquist complex planes; for BNII, only a simple capacitance loop appeared in the Nyquist plot at the same period. With the elongation of the immersion time, for BNII, two time constants appeared in the Nyquist plot; For CPII, the impedance spectrum shows a slightly depressed semicircular shape.

Al-Zr-M (M=Fe, Ce and Nd) alloys were prepared by arc melting. The structures of alloys were identified by X-ray diffraction (XRD). The electrochemical behavior of these alloys was studied by potentiodynamic polarization in 3.5% NaCl solution．The surface morphology of samples after corrosion was analyzed by optical microscope. The results show that the passivation in 3.5% NaCl solution for Al-Zr alloys with rare earth addition was easier than that without addition. The ability of corrosion resistance of alloy with Nd is superior to that with Ce. Because of active polarization, the current density of cathodic polarization for A1-Fe-Zr alloy was large, and low corrosion resistance was low.

Micro-arc oxidation (MAO) coatings were prepared on AZ91D magnesium alloys with same process. The corrosion resistance of coatings was characterized by immersion test, spot test and electrochemical tests, and the surface morphologies of coatings were observed with SEM. The results of six tests have shown that the corrosion resistance of magnesium alloys after MAO treatment is improved dramatically. The anti-corrosion ability of MAO coatings could not be presented properly with immersion test because it is hard to decide which evaluation criteria, weight loss or weight gain, should be taken due to corroded products that might be stuck in coatings with porous microstructure and were hardly eliminated completely. spot test has been considered as a quick way to detect the corrosion resistance of MAO coatings, but colour changing of drip liquid in the first place was adopted as proper counting point, and the concentration of nitric acid in drip liquid needed to be doubled when meeting coatings with good corrosion resistance in order to stimulate a corrosion action faster. Electrochemical tests have been considered to carry out the overall characterization of the corrosion resistance of MAO coatings properly, and more information such as corrosion potential, corrosion current and impedance etc could be obtained from the tests of cyclic voltammetry (CV), Tafel technique, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS), which in turn will enhance the further research on the corrosion behavior of coatings. Finally, the corrosion resistance of MAO coatings was closely related with the thickness and chemical composition of coatings and also with their internal and surface microstructure.

30%Ru-70%Ti/Ti anode coatings on titanium TA2 substrates were prepared by thermal decomposition method. The cationic surfactant cetyltrimethylammonium bromide (CTAB) was introduced into this process as a templating agent. The effect of the templating agent CTAB on the surface area and the electrocatalytic activity of the anodes were studied by chlorine evolution potential (ECl), cyclic voltammetry (CV), voltammetric charge capacity (q*), active sites (N_a) and roughness (R_f) tests. The results show that the using of templating agent CTAB had significant effects on reducing chlorine potential and enhancing electrocatalytic activity. The improvements of the electrocatalytic activity the RuO₂-TiO₂/Ti anodes can be attributed to two reasons: on the one hand, the high-surface areas and the porous oxide structures were obtained via CTAB, on the other hand, the porous oxide coatings had high-density structural defects, the surface active sites density was increased.

The oxidation behavior of Fe-5Y and Fe-10Y alloys was studied at 800℃ in air. The results indicate that the scaling kinetics is not irregular. The oxidation rate of Fe-10Y alloy is higher than Fe-5Y alloy. The scale formed on Fe-10Y alloy is substantially similar to that on Fe-5Y, also with severe internal oxidation. A single Y₂O₃ layer was not formed on the surface of alloy. These results were examined by taking into account the presence of intermetallic compounds in the alloys and the low ability of diffusion of yttrium in iron.

Co-Al-W alloy is a kind of novel Co-based superalloy strengthened by ternary compound γ'-Co₃(Al,W) phase with the precipitation strengthening on γ-Co matrix. The paper studies the kinetic of hot corrosion of Co-Al-W superalloy at 800℃ in 75% Na₂SO₄+25\% NaCl molten salt and the effect on hot corrosion behavior of Co-Al-W alloy with alloying elements of Mo, Nb, Ta and Ti. The results show that the alloy of 2Mo, 2Nb, 2Ta and 2Ti have the superior anti-hot corrosion ability compared to 9.8W alloy. The anti-hot corrosion ability of Co-Al-W alloy with alloying elements Ta and Nb are inferior to Co-Al-W alloy adding Mo and Ti elements. The hot corrosion oxide scale with alloying elements of Mo, Nb, Ta and Ti is still made up of three layers, that is the external corrosion layer consists of Co oxide CoO and Co₃O₄, the intermediate mixed oxides layer composed of complex oxide and nonuniform oxide layer of alloying elements, Co, Al, W and an internal attacked layer with different compounds of Co, Al and O. With the increasing of corrosion times, the intermediate mixed oxides layer becomes thicker, the thickness of internal and external layer almost has no change, but compactness of internal layer is gradually increased.

Corrosion behavior of mild steel in the condition of H₂S in wet/dry cycles was studied by corrosion analysis, corrosion product and morphology analysis and electrochemical measurement. The results show that the initial corrosion products are less, and corrosion rate is proportional to cycle times; with accumulation of more corrosion product, which possibly acts as corrosion barrier, corrosion rate is inversely proportional to cycle times based on comprehensive analysis. The formation of FeS may be a factor responsible for a turning point of corrosion rate.

Electrochemical corrosion characteristics and dendrites growth of lead-free Sn-0.7Cu solder on FR-4 printed circuit board plated with Cu were investigated by potentiodynamic polarization coupled with scanning electron microscope, energy dispersion X-ray analysis and X-ray diffraction analysis. The results showed that the corroded metal in solder alloy was primarily Sn, and the corrosive current density increased with electric field intensity increasing. In low electric field, uniform corrosion took place, while in high electric field, the inhomogeneous corrosion existed. “Bridge interconnection” caused by dendrite growth severely impacted on the reliability of electronic products due to short circuit. Results of EDAX analysis indicated that on dendrites the content of Cu was larger than Sn, which implied the electromigration and deoxidization capacity of Cu²⁺ were larger than those of Sn²⁺. There was crystal tropism characteristics for dendrite growth: the orientations with fastest growth rate were from four directions, the growth was spiraled from inter to outer, and the favor tropisms of crystal particles on dendrites were (411) and (220). The stronger the electric field intensity, the faster the growth of dendrites, the shorter the bridge time. The bridge time of two electrodes with 3 mm fine-pitch after dendrite growth was respectively 12.5 h for 8 V, 20.4 h for 5 V, 28.5 h for 3 V, and 39.6 h for 1 V. XRD showed that the primary corrosive products were SnO₂，SnCl₄, while the contents on dendrites were Sn，SnO₂，SnCl₄，Cu，CuCl₂.

The inhibition performance of lauric acid on N80 steel in CO₂ saturated NaCl solution at different pH values (4.9, 6.9 and 7.4 respectively) were investigated using electrochemical methods and the attenuated total reflection Fourier-transform infrared (ATR-FTIR). The results showed that lauric acid has more obvious inhibition ability to the cathode process in the lower pH value. While at higher pH value, the inhibition effect is more obvious to the anode process. At the middle pH value, it showed the transition-state characteristics and has the inhibition effect both to anode and cathode processes. The different adsorption state of the inhibitor at various pH values has different interaction with the metal surface which explains the difference of the inhibition performance in the test environments.

Cerium-doped TiO₂ film was prepared on 304 stainless steel by a sol-gel process. Sulfate-reducing bacteria(SRB) was incubated by semi-continuous culture method. The effect of SRB on corrosion behavior of cerium-doped TiO₂/304ss and bare 304ss immersed in SRB medium were studied by morphology analysis and electrochemical methods. The results showed that cerium-doped TiO₂ film on 304ss could inhibit attachment of SRB. The corrosion current density of cerium-doped TiO₂/304ss was lower, while electrochemical impedance was higher than that of bare 304ss. Therefore, a conclusion could be drawn that cerium-doped TiO₂ film coating on 304ss could inhibit attachment of SRB and prevent corrosion caused by SRB in seawater.

The effects of temper on EFC of 7150 alloy, which is prevalent on aging airplane structure, had been investigated by means of corrosion test on T6, T73 and T77 temper in oceanic environment and transmission electron microcopy (TEM). The test results shown that T77 temper was the best for EFC resistance, T73 temper was the next and T6 temper was the worst. The test results also shown that the wedging stress produced by the corrosion product at the grain boundary of 7150-T77 alloy can not sustain the EFC development. TEM observation shown that continuous η phase existed at the grain boundary of T6 temper. The grain boundary of T73 and T77 temper had PFZ zone and dispersed η phase. The PFZ of T77 temper was thicker than T73 temper. The particles of η phase at the grain boundary of T77 temper were coarser than T73 temper. We can draw a conclusion that the microstructure in grain boundary zone of 7150 alloy is the key factor to the EFC resistance.

The electronic property and photocurrent characteristics of passive films formed on J55 pipeline steel with tension，compression and bending stress conditions in the Changqing oilfield Luo-he stratum water were investigated through electrochemical impedance spectroscopy (EIS) and photocurrent techniques. The results showed that the transfer resistance R₁, the film resistance R₂ and diffusion resistance decreased with the increase of the tension stress, and increased with the increase of the compression and the bending stress. It was shown that the protective effect of passive film on J55 pipeline steel was increased with the decreasing of the tension stress and the increasing of the compression and the bending stress. Mott-Schottky plots revealed that the slope of M-S plot decreased with the increasing of the tension stress and the decreasing of the compression and the bending stress, it can be concluded that the donor density of the passive film increased with increasing the tension stress and decreasing the compression and the bending stress. The photocurrent measurement indicated that the photocurrent decreased with the increasing of the tension stress and the decreasing of the compression and the bending stress.

This review describes the recent advances in the basic principles and applications of local electrochemical measurement techniques. The focus of this review is on the application of electrochemical methods, such as scanning vibrating electrode technique (SVET), scanning Kelvin probe (SKP), localized electrochemical impedance spectroscopy (LEIS) and scanning electrochemical microscopy (SECM) in the field of corrosion and protection, both on theories and techniques. The spatial resolution and reliability of local electrochemical measurement techniques greatly increases the utility of these techniques for the characterization of localized corrosion and the electrochemical behavior of single and mixed phase structure. Researches, by using advanced local electrochemical measurement techniques in the areas of localized corrosion and the electrochemical behavior of single and mixed phase structure, are aimed at accumulating corrosion experimental data and accelerating the development of these techniques.

The metal corrosion is a significant impact for the national economic, and the wave splash zone is a most serious regional that caused a variety of metal corrosion. However, as the complex nature environments of splash zone, the research is lack in this area. In order to research the environmental impact of splash zone across-the-board, This paper summarizes the definition of splash zone as well as its unique environmental factors on the basis of previous studies, eg. irradiation, alternating wet and dry, Cl^-, temperature, dissolved oxygen and so on, analyzes and summarizes the wave impact pressure acting on the cylindrical characteristics and laws. The wave force includes the level of drag force and the level of inertial force, whose wave form resembles a sine curve and time cycle is consistent with the wave force. However the tidal current is a steady uniform flow at a set speed, the article also provides a reference in stress corrosion and corrosion fatigue in spray splash zone for future research, and the development trends in this field were also presented.