An EFM system for corrosion rate test based on electrochemical frequency modulation technique has been established by means of virtual instrument， which consists of a potentiostat， a laptop equipped with a DAQ card and applications developed in LabVIEW. Experiments has been performed in laboratory to determine anodic and cathodic Tafel slopes as well as corrosion current densities for the systems 304 stainless steel/HCl and Q235 steel in H2SO4 and NaCl.It was shown that the EFM system could be used successfully for corrosion rate mea?鄄surement under various corrosion conditions.

The effects of hydrogen on corrosion behavior and passive film of nano-crystalline stainless steel coat?鄄ing in 0.5 mol/L NaCl + 0.05 mol/L H2SO4 solution were investigated using electrochemical technique, X-ray photoelectron spectroscopy (XPS) analysis and scanning electron microscopy (SEM) observation. During the for?鄄mation process of passive film, the hydrogen could slow down the formation of the passive film because the exis?鄄tence of hydrogen would reduce the adsorbed OH- ions on the coating surface. XPS analysis results indicated that the OH-/O2- ratio in the passive film was changed after hydrogen charging. The susceptibility to pitting of the charged coating was enhanced because of the increment of OH-/O2- ratio in the passive film.Mott-Schottky analy?鄄sis showed that the hydrogen protons could enhance the dielectric constant of the passive film and account for the increase in capacitance and carrier density of passive films. In addition, the passive current density decreased and the carrier densities increased with the increment of hydrogen charging current.

Stress corrosion cracking (SCC) mechanism of pipeline steel X70 has been investigated in a solution of near-neutral pH by means of slow strain rate test and electrochemical test technology. The experiments showed that SCC susceptibility increased as the applied potential shifted in the cathodic direction, but when the potential was lower than the extent of susceptive potential, SCC susceptibility depressed. Besides, the susceptive potential became more negative as the pH value decreased and corrosion rate increased. The analysis showed that hydrogen-induced cracking together with anode dissolution played an important role in the SCC of pipeline steel X70. However, anode dissolution and hydrogen-induced cracking did not work separately. Hydrogen permeation was related to the process of hydrogen deoxidization and the anode dissolution at specimen surface. Relevant potential was able to make the two mechanisms combined to cause much more serious SCC.

The pre-cracking specimens of X70 pipeline steel were pre-charged with hydrogen in 0.5mol/L H2SO4 solution,and then extended in air to fracture in order to obtain the fracture roughness of the cracking bodies. When the hydrogen concentration was less than 0.978×10-4 mass%,the hydrogen made the fracture roughness in?鄄crease 11.8%. When the hydrogen concentration was more than 0.978×10-4 mass%, the hydrogen made the frac?鄄ture roughness decrease according to the linear relationship of the hydrogen concentration.The fracture surfaces were characteristic of the dimple and the diameter of the dimple varied smaller with the gradual increase of the hydrogen concentration. On the slow strain rate tension tests with dynamically charging with hydrogen in 0.5mol/L H2SO4 solution,the fracture roughness decreased considerably.The fracture roughness for hydrogen-induced cracking decreased linearly with exponential function of charging current density. The hydrogen-induced fracture had appearance of the quasi-cleavage.

Using the NACE standard bent-beam test, sulfide stress corrosion cracking (SSCC) of different types microstructure in X70 grade pipeline steel with different types of microstructure was investigated. The X70 pipeline steel are all obtained from Ansteel, The result showed that the X70 pipeline steel had the excellent performance to the SSCC and the microstructure dominated by fine and homogeneous acicular ferrite had the excellent resistance to SSCC. Both the high density tangled dislocation and carbonitride precipitiated along with dislocation networks are the main reasons for the steel with acicular ferrite to have excellent resistance to SSCC. The microstructure is the main factor to decide the SSCC performance.

The adsorption behavior of imidazoline derivative as a cationic inhibitor for inhibiting galvanic corro?鄄sion has been investigated by using electrochemical methods, atomic force microscopy (AFM) and Fourier trans?鄄form infrared spectroscopy (FTIR) technology. The results show that the inhibitor adsorbs on the surface of carbon steel while it does not adsorb on the surface of stainless steel in aqueous NaCl solution. When the two metals are electrically coupled in NaCl solution, the inhibitor can adsorb to the surface of both carbon steel and stainless steel. However, in this case, the surface coverage of the inhibitor film formed on the carbon steel decreases com?鄄pared with that on the surface of single carbon steel immersed in the same electrolyte, and the adsorbability of the inhibitor on the surface of carbon steel is weakened. The corrosion failure for carbon steel of the couple at?鄄tributes to the decreases of both coverage and adorability of the inhibitor adsorbed on the metal surface.

Influence of microbes on corrosion of carbon steel was studied by means of polarization curves,electrochemical impedance spectroscopy(EIS),scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The results showed that as the existencl of sulfate-reducing bacteria (SRB), the corrosion rate of carbon steel buried in unsterilized contaminated soils was higher than that of in sterilized contaminated soils. EDS results showed that sulfur existed in corrosion product of carbon steel in unsterilized contaminated soils, and it can be owned to the function of SRB.

Fatigue tests were performed using a special developed testing machine for 304 stainless steel micro-sized specimens in both the laboratory air and the aggressive (0.9% NaCl solution) environments. The experimental results showed that corrosion behavior on the surface of micro-sized specimens was mainly general corrosion and no obvious corrosion pits were found after pre-corrosion. Corrosion fatigue life of micro-sized specimen in air is about 107 cycles, which is about 10~100 times larger than that of the micro-sized specimen in corrosive solution. The decreasing value of maximum load was monitored during the course of corrosion fatigue tests and rapid decreasing value was observed at the terminal stage of corrosion fatigue tests. A detailed fractographical analysis was presented and no long corrosion fatigue crack was found on the fracture surface.

The effect of temperature on CO2 corrosion process of N80 steel in simulated stratum water was detected using electrochemical impedance spectroscopy (EIS).The results showed that in the spectroscopy appeared three time constants,i.e.,the capacitance of high frequency,the inductance of middle and low frequency,the capacitance of low frequency. The capacitance appearing at high frequency is related to the capacitance of the double layer and transfer resistance, the inductance is attributed to the dissolution of the film, and the capacitance of low frequency is related to the formation of the film. With the temperature increasing, the inductance shrank, and the capacitance in low frequency enlarged, these indicated that increas temperature may accelerate the formation of the corrosion film. The transfer resistance of corrosion process increased with the increment of temperature and prolonging the immersion time,this is related to the compact property of the corrosion film.

Aimed at the corrosion of G105 drill pipes in aerated drilling fluids, the impact of dissolved oxygen of 3.5% NaCI solution on the corrosion behavior of G105 steel was studied using weight loss method.The tests revealed that the corrosion of G105 steel in brine was considered as oxygen corrosion; the temperature and dissolved oxygen affected the corrosion rate of G105 steel in aerated 3.5%NaCI solution:at the same temperature,the corrosion rate increasing with the content of dissolved oxygen;at the same aerated condition,the corrosion rate increased when the temperature was elevated from 25 ℃ to 65 ℃ and reached the maximum at 65℃.The corrosion rate of the G105 steel and dissolved oxygen of 3.5%NaCI solution obeyed linear relationship.

This paper presents an analytical study on two ternary Cu-Sn-Pb systems forged by using the Chinese traditional casting technique with difference in the amount of tin 15%. We had some of these copper alloys heat?鄄ed under different temperatures, then kept all the heated and unheated samples under an acid and chlorine-rich environment for several days.With the combined use of XRD analysis and metallographic examination, corrosion resistance of copper alloys was carefully discussed. The delta phase decomposed or diminished while the alpha phase recrystallized. When a proper temperature was chosen for reheating, the delta phase was found eliminated and the intergranular structure changed again. This experiment indicates that by doing so the corrosion resistance of copper alloys can be greatly improved, which in return helps controlling the outbreak of bronze disease.

The effect of cathodic delamination on the degradation of organic coatings and the corrosion under?鄄coating were reviewed. The factors affecting the initiation and propagation of cathodic delamination， the mecha?鄄nisms of cathodic delamination and the methods to improve the cathodic delamination resistance of organic coat?鄄ings were discussed. At the same time， the measuring methods and techniques for the studies of cathodic delami?鄄nation of organic coating were reviewed， too.

performance evaluation techniques of coating and film on stainless steel are reviewed. The film and coating on stainless steel covered in this paper are colored film prepared by either by electrochemically or chem?鄄ically， passive film after polishing and cleaning， thermal barrier and ceramic coating and so on. Detail discus?鄄sion of each technique is focused on the suitability， reliability and performance indicator（s） an evaluation pro?鄄cess could generate. Additional performance indicator if available and not mentioned in previous researches is al?鄄so suggested by authors with an intension to extend the existed technique and generate more performance infor?鄄mation. At the end of each category， the applicable ISO， ASTM， DIN and GB standards are discussed and com?鄄pared for encouragement of the possible adoption of standards.