The corrosion problems significantly reduce the mechanical properties of metal materials, destroy the geometric shape of metal components, shorten the service life of equipments, and even cause disastrous accidents. For this reason, Division II focuses on the surface science, corrosion and aging failure problems of engineering material and components under the atmospheric environment in the fields of industrial and city infrastructure.
Among the research topics, the corrosion behaviour of pipeline under the condition of multiphase flow is one of the biggest research interests for Division I. Consequently, the corrosion mechanism and protection of pipeline under high salinity water, dissolved oxygen, CO2, H2S, sulfate reducing bacteria and chloride ions, etc, are studied by Division I.
1.Multi-scale experimental evaluation of corrosion behavior
2.Multi-scale modeling of corrosion behavior
3.Multiphase flow corrosion research in oil and gas field
4.In-situ/Ex-situ advanced characterization of interfacial processes
5.High-throughput corrosion experimentation and data collection
6.Surface modification of alloys
7.Corrosion rate and corrosive environment monitoring
1.Based on the scale domain scientific problem of metal corrosion, multiscale evalution and cross-scale simulation prediction of metal corrosion are carried out through experiments as well as simulation such as DFT (Density Functional Theory), finite element model etc. A series studies based on finite element model was developed to simulate localized corrosion of metal. Local corrosion of aluminum alloys driven by micro-galvanic effects was simulated by a finite element model shown in Fig. (a). The effect of density of Al(OH)3 precipitates generated both on the electrode surface and in the liquid phase was explored.
(a)Schematic diagram of the model. (b) The precipitated Al(OH)3 in the whole liquid phase after 70 hours with different εc values.(c) Local pH in the electrolyte after 70 hours with different εc values.
2.A local electrochemical test system which combines a capillary device with a photolithographic mask has been developed to investigate the local electrochemical properties of a predefined micron-sized area with greater reliability and versatility than existing approaches. The 309L-SA508 fusion boundary (FB) in a SA508-309L/308L overlay cladding weldment was characterized by multi-analytical approaches. Local electrochemical properties around the FB region were investigated in 3.5 wt% NaCl solution by utilizing a self-developed microcell setup combining lithography and capillary techniques (high throughput micro-area electrochemical measurement system).
Schematics of the proposed local electrochemical test system. (a) Microcapillary cell system; (b) Enlargement showing the capillary tip and the masked specimen
The selected test sites for electrochemical measurements: (a) a view of positions of the four exposed test areas, (b)~(e) metallographic images of P1 (A+M), P2 (CF + M), P3(CF + M) and P4 (CF), respectively.
3.Effect of hydrostatic pressure (HP) on the corrosion behaviour of X80 pipeline steel served in deep sea environment was inveatigated. HP significantly accelerates the corrosion rate of X80 pipeline steel. The promotion of corrosion process by HP includes the acceleration of γ-FeOOH reduction reaction, enlarged cathodic reaction area and the promoted penetration of to destroy the integrity of corrosion layer.
Potentiodynamic polarization curves of X80 pipeline steels at different HPs(a) and Raman spectra of the corrosion products after 24 h immersion at different HPs(b).
4. Sweet (CO2) corrosion has been one of the most widespread and prominent problems in the oil and gas industry for a long period. The corrosion behaviors of 13Cr martensitic steel under different CO2 partial pressures (up to 28 MPa) were investigated. A detailed calculation on the pH values and phase concentrations of the solutions was carried out to investigate the influence of CO2 partial pressures on the stability of passive film and the formation of the corrosion film on 13Cr stainless steel surface in CO2 environments. A model is proposed for the film formation on the 13Cr steel surface under different CO2 partial pressures.
(a) Corrosion rates of 13Cr stainless steel under different CO2 partial pressures of 4~28 MPa; (b) Schematic diagram of the corrosion film formation on 13Cr steel surface.
5.Superhydrophobic coating: The super-hydrophobic coating with high wear resistance were fabricated. By adjusting the micro/nano structures and low surface energy materials, the wetting properties of the as-prepared surfaces were studied systematically.
Wetting properties of the as-prepared superhydrophobic coating with the abrasion distance.
6.Series studies of pH sensor based on iridium oxide has been investigated: An iridium pH sensor fabricated by cyclic heat treatment and quenching process was proposed, which illustratd wide pH response range, near Nernst E-pH response sensitivity, fast response rate, and good long term stability, etc(Fig. a). A potential compensation method with a specially designed probe structure was proposed to correct possible errors caused by the potential drift of metal oxide electrode in long term pH monitoring(Fig. a). Nafion modification of the pH electrode could effectively exclude the effects caused by reductive anions (Fig. b). Successful application of iridium pH electrode in surface pH detection of zinc/steel galvanic couple in corrosive solutions broadcasts the wide application fields of the electrode (Fig. b).
(a) Sensor development and corresponding property tests results; (b) Modification and application of pH sensor.
7.The effect of atmospheric parameter on the corrosion process of the manufacturing complex composite material parts has been investigated. The multiphysics fields, including velocity, temperature, relative humidity and fluid composition, have been analyzed to estimate the corrosion grades and position for the structure parts, for establishing a service-life prediction model.
(a) The heat transfer coefficient on the steel-structure surface; (b) The volume fraction of the liquid water in CUI (Corrosion Under Insulation) process.