Xiutong Wang

CdTe and graphene co-sensitized TiO2 nanotube array photoanodes for protection of 304SS under visible light

CdTe/graphene/TiO2 films that served as photoanodes for cathodic protection application were prepared by an electrochemical deposition method. The deposition of graphene and CdTe nanoparticles (NPs) on the surface of the TiO2 nanotubes was confirmed by scanning electron microscope and transmission electron microscopy. The composites exhibited high light absorption in both the UV and visible light region. The results indicated that TiO2 nanotube photoelectrodes sensitized by 20-cycle graphene and 30-cycle CdTe NPs exhibited effective photocathodic protection properties for 304 stainless steel (304SS) under the visible-light illumination, with an photopotential of -750 mV versus saturated calomel electrode and a current density of 560 μA cm(-2). Due to the efficient photogenerated charge separation, the three-component CdTe/graphene/TiO2 showed stronger photoresponse than pure TiO2 under visible-light illumination. In summary, the CdTe/graphene could improve the photocathodic protection properties of TiO2 films.

Corrosion of steel structures in sea-bed sediment

Seabed sediment (SBS) is a special soil that is covered by seawater. With the developments in marine oil exploitation and engineering, more and more steel structures have been buried in SBS. SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed here.

Effect of molecular structure of aniline–formaldehyde copolymers on corrosion inhibition of mild steel in hydrochloric acid solution

Aniline-formaldehyde copolymers with different molecular structures have been prepared and investigated for the purpose of corrosion control of mild steel in hydrochloric acid. The copolymers were synthesized by a condensation polymerization process with different ratios of aniline to formaldehyde in acidic precursor solutions. The corrosion inhibition efficiency of as-synthesized copolymers for Q235 mild steel was investigated in 1.0 mol L(-1) hydrochloric acid solution by weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. All the results demonstrate that as-prepared aniline-formaldehyde copolymers are efficient mixed-type corrosion inhibitors for mild steels in hydrochloric acid. The corrosion inhibition mechanism is discussed in terms of the role of molecular structure on adsorption of the copolymers onto the steel surface in acid solution.

Effect of sulphide pollutants on mild steel corrosion in 3·5% NaCl solutions

Abstract Corrosion behaviour of mild steel in 3·5% NaCl solution containing sulphide pollutants was investigated using potentiodynamic polarisation measurement, electrochemical impedance spectroscopy and scanning electron microscopy. Reaction and mechanism of the corrosion process were discussed. The study shows that sulphide concentration had a remarkable effect on pitting corrosion. Sulphide pollutants exhibited inhibition effect with passive film in the initial stage of corrosion. When the passive film breaks down, sulphide would accelerate the corrosion process.

ZnFeAl-layered double hydroxides/TiO 2 composites as photoanodes for photocathodic protection of 304 stainless steel

A series of ZnFeAl-layered double hydroxides/TiO2 (ZnFeAl-LDHs/TiO2) composites are synthesized by a combined anodization and hydrothermal method. The structure, surface morphology, photo absorption and photocathodic protection properties of these samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) and electrochemical tests. The unique structure of the ZnFeAl-LDHs reduces the charge carriers recombination, and the visible photoresponse property increase the light harvesting. The XPS study reveals that the electrons in the ZnFeAl-LDHs travel to TiO2, and the ZnFeAl-LDHs/TiO2 composites generate and transfer more electrons to 304 stainless steel (304SS), and exhibits a better photocathodic protection performance than pure TiO2. In addition, after intermittent visible-light illumination for four days, the photoanode still exhibits good stability and durability.

Preparation and photocathodic protection property of ZnIn2S4/RGO/TiO2 composites for Q235 carbon steel under visible light

For improving the photocathodic protection performance of TiO2 photoanode, ZnIn2S4/reduced graphene oxide (RGO)/TiO2 nanotubes (NTs) composite was synthesized by electrochemical anodizing combined with hydrothermal method. The photoelectrochemical and photocathodic protection properties of the ZnIn2S4/RGO/TiO2 composite were investigated in detail. Compared with pure TiO2 NTs, the ZnIn2S4/RGO/TiO2 composite showed a significant improvement in photocathodic protection performances. The photogenerated open circuit potential drop of ZnIn2S4/RGO/TiO2 coupled with Q235 carbon steel in 3.5 wt% NaCl solution under visible light could reach 420 mV versus saturated calomel electrode, which was more than twice as much as that of pure TiO2. The photogenerated current density of ZnIn2S4/RGO/TiO2 could reach 5.6 mA cm-2, which was twice as much as that of pure TiO2. The appearance of the adsorbed oxygen (OA) enabled the ZnIn2S4/RGO/TiO2 to have better photo-carrier separation efficiency and better photogenerated cathodic protection than pure TiO2. The present work demonstrated ZnIn2S4/RGO/TiO2 could be a potential material for photoanodes because of its better visible-light response, higher electrical conductivity and smaller charge transfer resistance.

Corrosion behaviour of carbon steel, titanium and titanium alloy in simulated underground water in Beishan area preselected for nuclear waste repository in China

ABSTRACT The groundwater will completely infiltrate to the surface of nuclear waste container after the closure of its deep geological disposal. Therefore, the corrosion behaviour of Q235 carbon steel, titanium and titanium alloy, which were the candidates as the container materials for high-level nuclear waste disposal in simulated groundwater solution of Beishan to be served as the preselected high-level nuclear waste disposal area in China at different temperatures, was studied through electrochemical methods including open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarisation curve measurements. The results show that the corrosion rate of titanium and titanium alloy is lower than that of carbon steel at all temperatures, and they are more promising as container materials. Another phenomenon is that higher temperatures facilitate the protection performance of corrosion products compared with lower temperatures.

Multichannel cathodic protection monitoring system for offshore structures

A cathodic protection (CP) monitoring system with multichannel technology has been used for an offshore oil jacket. The design, installation, data transfer, and processing have been described. The monitoring potential and current from the anodes showed that the system is in good operating condition and that the offshore jacket has adequate protection.

Effect of the Ammonia Nitrogen on Corrosion Behavior of Steel in 3.5% NaCl

The land-sourced pollutants including industry wastewater and sewage bring to the coast zone sea pollution. The pollutants in the seawater can aggravate or reduce the corrosion of the steel. Among them the ammonia nitrogen is an important factor. In this paper the effect of the ammonia nitrogen on corrosion in 3.5% NaCl solution was discussed. Two types of steel were selected for the research. Scanning electron microscopy and electrochemical technology was used to investigate the effect.