Corrosion of A210-C carbon steel tube has been investigated after 1000h exposure at the place close to the bubbling bed of a bench-scale fluidized-bed combustor during firing a coal of low sulfur and high chlorine. It was foound that a heavily exfoliation of the wastage occurred in locations with the tube surface temperature of 460℃-560℃.The spalled wastage was mainly composed of hematite(Fe2O3) covered by a layer of deposits. (K,Na)Cl was locally detected in the deposits layer. By investigation of the residual wastage on the carbon steel tube,some locations at/near the interface of the wastage and the metal substrate did appear chlorization, which led to three different consequences:(1)formation of FeCl2 layer underneath the eastage,(2)rapid local corrosion,causing protrusions into the metal,(3)appearance of internal pores in the metal. The generation of the different morphologies above and effect of chlorine were both discussed in detail.

The healing mechanism of hydrogen-attacked crack and its influencing factors to the low carbon steel and Cr-Mo steel during the healing process was studied by recovering heat treatment of split specimens in vacuum. The result showed that crack pacing turned much smaller under the condition of pure heating, especially for crack tips. The healing effect was well related to the length of cracks with the shorter in priority. By the primary mechanism of thermal diffusion, iron and carbon atoms must diffuse at the high speed in steel to realize that plasticity deformation energy(Es) exceeds and overcomes surface tensile force energy. In addition, phase transformation and stress-strain relationship also have positive effects on the process.

Four alloys with different morphology and microstructure were prepared by adding different amount of niobium to equal atom-ratio TiAl-based intermetallic compound. Interrupted oxidation behavior of the four as-cast high-Nb TiAl alloys and binary TiAl alloy at 1000℃ in static air was studied using oxidation mass gain analysis. The structure and component of the oxide scales were analyzed by XRD\SEM and EPMA. Results indicate that Nb enhances oxidation resistance of the alloy. The alloy Ti-42.8Al-14.2Nb consisting of main phase of γand α2 forms the protective oxide scale. However, excessive addition of Nb results the existence of Nb-enriched phase in the alloy and the formation of Nb2O3 in oxide scale, simultaneously the oxide scale structure becomes porous. It leads to the multi-layered scale, accelerating the spallation of the oxide.

The stress corrosion cracking(SCC) behaviior of X70pipeline steel in near-neutral-pH solutions at different applied potentials and the effect of different levels of CO2 on SCC were studied with slow strain rate testing (SSRT). The results showed that the cracking mode of X70pipeline steel in near-neutral-pH solutions was transgranular, with the features of quasi-cleavage. The susceptibilit to SCC increased as the applied potential moved towards the cathodic direction The value of pH decreased with the increased addition of CO2 in the solution, which increased the susceptibitlity to SCC. Hydroge induced cracking(HIC) dominated the process.

The autoclave experiments were applied to investigate stress corrosion cracking(SCC) behaviors of alloy 800 under different shot peening conditions in 300℃ ,50mass% NaOH solution. The effect of shot peening was discussed either. The final passive films developed on the alloys which have no SCC after 3000 hours in solution were studied by Auger electro spectroscopy and X-ray photoelectron spectroscopy. The results showed that shot peeing creates a compressive residual stress over the alloy surface and could protect against stress corrosion cracking effectively. XPS results showed that the films formed on alloy surface have a trilayered structure in which the topmost layer is composed of pure nickel, followed by an outer part of carbolic grains and an inner part of Cr2O3 and a little nickel oxide. Because the topmost nickel disappearedin protective layer and the circumstance became execrable the corrosion proceeds.

A prediction model for corrosion damage of aluminum alloys was developed and the nonlinear relationship between maximum corrosion depth, fatigue performance and corrosion temperature, corrosion time was established based on MATLAB, using BP(Back Propagation) algorithm of neural network. The corrosion trend of aluminum alloys can be predicted by this means. Four-layer network and three-layer network were used, and the effects of structure model of neural network on the precision were discussed. The results show that the former is more precise than the latter.

Under the same conditions, the Al-Mg alloys surface treatment was performed by the microarc oxidation with different components of electrolytes. The thickness of the microarc oxidation coating was measured by the thickness gauge. Surface morphology and composition of the coating were analyzed by scanning electron microscopy(SEM) coupling with energy dispersive X-ray(EDS); the adhesion between the oxidation coating and the substrate was evaluated by means of the file. The results showed that the high stoichiometry of the phosphorus element increased the growth rte and the compactness of the oxidation coating, decreased its porosity, boosted up the adhesion between the oxidation coating and the substrate, and influenced the composition of the microarc oxidation coating. At the same time, the molecule polymerization state had an effect on the growth rate and the porosity of the coating, on which the linear polymer had a more useful impact than the cyclic polymer did.

The interfacial electrochemical behaviors of the interaction of marmatite with flotation reagents in 0.1mol/L KNO3 media were studied by potentiodynamic and impedance measurements. The results indicated that the corrosive potential of marmatite almost is not affected by pH values, but its corrosive current rises, and hydrophobic sulfur on marmatitie surface decreases rapidly and hydro action becomes obvious with the rising of pH values; that diethyl dithiocarbamate is a corrosive reagent and an inhibitor for the flotation of marmatitie;Ca(OH)2 is the best reagent for adjusting pH in alkaline flotation system.

It was studied that the effect of temperature, partial pressure of CO2, pH value of solution and concentration of Cl- on corroison behavior of 4 types of steels, which include N80, P105, P110 and SM110 thimble using in oilfield. At 90℃ , the corrosion rate of all metals reached maximum value. At 65℃ , except P105, the corrosion rate of other materials increased with pressure of CO2 increasing, however, it reached maximum value at 2.5MPa pressure of CO2 when the temperature was 90℃ . The influence of pH value of solution and Cl- concentration of Tarim oil field on corrosion rate of metals investigated were lightly.

The effect of IMC-80-Q(quaternary alkynoxymethyl amine) on the electrochemical behavior and inhigitor properties of N80 steel in 3% NaCl saturated by CO2 at 25℃ 1℃ under flowing conditions had been studied by weight loss and electrochemical techniques including EIS and linear polarization by using rotating discelectrode. The results showed that the cumulative mass loss increased greatly in the blank solution when flow velocity was higher than 4m/s, and the critical flow velocity for the blank solution was about 4-5m/s. The extreme-value-phenomena of concentration existed for IMC-80-Q under both flowing and static condition. 150mg/L was the best inhibitor concentration when flow velocity was lower than 5m/s. In contrast, higher inhibitor concentration(300mg/L for 7m/s and 9m/s) was required if flow velocity was higher than 5m/s.

The relationship between corrosion inhibitor efficiency of some cyclic nitrogen compounds and their electronic properties of molecules has been carried out by using the quantum chemistry calculation, at the level of B3LYP with the 6-31G base sets. The chosen 5 compounds are:3-amino-1,2,4-triazole(3-ATA), 2-amino-1,3,4-thiadiazole(2-ATDA), 5-(p-tolyl)-1,3,4-triazole(TTA), 3-amino-5-methylmer-capto-1,2,4-triazole(3-AMTA) and 2-aminobenzimidazole. The reactivity was analyzed in terms of the Fukui indices. It is found that the molecules involved in this study are planar structure with conjugate system and the corrosion inhibition efficiencies have a certain linearity relation to energy of HOMO, the energy gap between LUMO and HOMO. It may be considered that these compounds are absorbed on the metal surface because the nitrogen atoms, which belong to pyridine type, offer electron pairs to the unoccupied atomic orbital.

The development of vapor phase inhibitor was reviewed in terms of its inhibiting grooup and molecular structure in this paper The relation between inhibition function and inhigition group was discussed. Demonstrate the electrochemical and physical and chemical inhibiition mechanism and the factors, such as the structure of inhibitor, temperature, and so on, affect the rust prevention by molecular structure theory. Some development directions of vapor phase inhibitor were discussed in future.

The present status and development of research methods on atmospheric corrosion were comprehensively reviewed. Acclelerated laboratory test, electrochemical measurements and in-situ monitor tecnology were emphatically introduced. Wet and hot test, salt spray test, periodic spray complex test, wet and dry intermittent immersion cyclic test, multi-factor complex accelerated corrosion test. While multi-factor complex accelerated corrosion test is the development trend in the future;electrochemical measurement technology for studying the corrosion mechamism in the thin layer electrolyte was generated:atmospheric corrosion monitor and kelvin probe vibrating capacitor technique, polarization and impedance measurement methods was usually used to cyclic wet and dry accelerated test and also used to test electrochemical behavior of sample wit rust in the immersion solution;the application of in-situ monitor technology contributed to launch the research on the mechanism of atmospheric corrosion from microcosmic aspect. In the end, this article puts forward the development trend of the future of atmospheric corrosion research methods.