Steel In Seawater Research Articles

Significance of an in-situ generated boundary film on tribocorrosion behavior of polymer-metal sliding pair

Polymer composites have a high potential for applications as tribo-materials exposed to sea water owing to their self-lubrication characteristic and high chemical stability. In the present work, tribological behaviors of polyetheretherketone (PEEK) composites rubbing with stainless steel in sea water were explored using a pin-on-disc tribometer integrated with a potentiostat for electrochemical control. It was demonstrated that further adding 5 vol% hexagonal boron nitride (h-BN) nanoparticles into PEEK reinforced with short carbon fibers (SCF) significantly enhanced the wear resistance. Moreover, the stainless steel exhibited significantly enhanced tribocorrosion resistance when rubbing with the hybrid nanocomposite, in comparison to the sliding against PEEK filled only with SCF. Nanostructures of the boundary films formed on the steel surface were comprehensively investigated. It was manifested that tribo-chemistry products of h-BN, i.e. H3BO3 and B2O3, were arrayed in a closely packed boundary film. It seems that inclusion of layer-structured H3BO3 and B2O3 improved the resilience of the boundary film. The continuous boundary film covering the steel surface provided a lubrication effect and strengthened the passivation layer. A new route for enhancing simultaneously tribological and corrosion resistance of polymer-metal pairs by controlling in-situ tribo-chemistry was thus proposed.

Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel.

This study examined the synergic effect of alloying the element Cr and the environmental element Mg2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) tests and weight-loss tests. The Mg2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe2O4 and a mixed layer (Cr oxide + FeCr2O4 + MgCr2O4) improved the corrosion resistance of the low-alloy steel in the seawater.

Effect of Desulfovibrio sp. and Vibrio Alginolyticus on Corrosion Behavior of 907 Steel in Seawater

Effect of Desulfovibrio sp. and Vibrio Alginolyticus on Corrosion Behavior of 907 Steel in Seawater

Nghiên cứu ảnh hưởng của sinh vật bám bẩn trong môi trường nước biển tới hiệu quả bảo vệ chống ăn mòn bằng phương pháp protector

The use of zinc protector for corrosion protection against steel and alloys in seawater are usually calculated according to the major technical parameters including electrochemical equivalent, location, shape, size and weight. However, in tropical marine environmental conditions, bio-fouling is participated. They grew very quickly and covered the entire surface of both the protector and materials and caused physical barriers which affect the material protection. The study was done in natural seawater and sterilized seawater in 12 months. The results indicate that bio-fouling strongly affected the corrosion rate of mild steel in seawater. However it also indicated that the zinc-based protector still guarantees protection effectivity even when it was completely coated by macrofoulers. In addition, at two months time point, the biomass on the protected samples was less than that compared to the unprotected samples. This can be explained by the fact that the sample surface is smoother (due to less corrosion) and therefore marine organisms are more difficult to foul. The effects of biofouling on the corrosion rate of protected mild steel samples by zinc protector are negligible.

Tribocorrosion behaviors of multilayer PVD DLC coated 304L stainless steel in seawater

The multilayer DLC coating was successfully fabricated on the surface of 304L stainless steel and silicon wafers by unbalanced magnetron sputtering technology. The tribocorrosion tests were carried out in a triboelectrochemical cell using a ball-on-plate tribometer integrated with a potentiostat for electrochemical control. Results showed that the open circuit potential (OCP) and corrosion potential (Ecorr) of 304L substrate presented great fluctuation. However, the OCP and Ecorr values of the multilayer DLC coating remained relatively stable during these tests. Meanwhile, the friction coefficient decreased and the wear-loss increased with the polarization potential increased from −1 to 0.5V. In addition, with an increase in polarization potential, the mechanical wear decreased obviously and the corrosion-induced wear gradually occupied a dominant position for 304L substrate, nevertheless, the mainly volume loss of the multilayer DLC coating was mainly attributed to pure mechanical wear. Thus, the tribocorrosion resistance of the multilayer DLC coating was superior to 304L substrate in seawater, manifesting its good potential as a protective material for marine industry.

Effect of load ratio and saltwater corrosive environment on the initiation life of fatigue of 10Ni5CrMoV steel

Fatigue initiation life has been studied with 10CrNi5MoV steel for use in ocean engineering at different load ratios and in different environmental media. The microstructure and micro-topography have been observed and analyzed by means of SEM, EDS and EBSD. Our findings indicate that, the initiation life of 10Ni5CrMoV steel in seawater is shorter than that in air, and the difference in longevity is larger with the increasing of load ratio. Corrosion pits had a great influence on initial corrosion fatigue life.

The research of axial corrosion fatigue on 10Ni3CrMoV steel

Fatigue life had been studied with 10CrNi3MoV steel at different load ratios and in different environmental medias. The microstructure and micro-topography had been observed and analyzed by means of SEM, EDS and TEM. Our findings indicated that, the fatigue life of 10Ni3CrMoV steel in seawater was shorter than in air, the difference in longevity was larger with the decreasing of axis stress. Corrosion pits had a great influence on corrosion fatigue life.

Tribological behavior of plastic composites and stainless steel in seawater

The tribological behaviors of poly(tetrafluoroethylene) (PTFE) against 9Cr18Mo, PTFE against glass fiber–epoxy resin (GFER), 316L against PTFE and polyamide 66 (PA66) against PTFE in natural seawater were evaluated in this study by using an MMU-5G friction and wear tester. The tribological test results show that the friction coefficients, seawater temperature and wear rates of the four friction pairs decrease in the following order: PTFE–9Cr18Mo > 316L–PTFE > PTFE–GFER > PA66–PTFE. The images from a confocal laser scanning microscope reveal the wear mechanisms of the four friction pairs during seawater lubrication. The results indicate that the worn surface of 9Cr18Mo exhibits corrosion together with scattered pitting, but the worn surface of 316L is smooth and uncorroded. The worn surface of PTFE for the friction pair of PTFE–GFER is smoother than the original surface. The counterface (GFER) is covered with several PTFE transfer films that help to decrease the friction coefficient and wear rate. During sliding, the friction pair of PA66–PTFE shows excellent wear behavior because the worn surface of PA66 is covered by the PTFE film. The PTFE wear rate significantly increases when the PTFE sliding against 9Cr18Mo occurs in seawater given the serious plastic deformation of PTFE when the surface temperature is increased.

Pitting corrosion of older underground cast iron pipes

ABSTRACTMajor water supply distribution networks in many cities consist of buried cast iron pipes. Often the pipes are internally cement-lined. For these the most severe external pitting corrosion is important because this may cause leakage and eventual structural failure. Herein representative data is reported for 10 pipes, ranging in age from 34 to 129 years and from 200 to 600 mm diameter that are part of a larger data set. The pipes examined were selected by the water utilities from several critical locations. Pit depths over 1–2 m lengths of pipes were measured and examined and soil properties measured. The morphologies of pitting around the pipes were found to be very different, with often much greater pit depths and larger pit areas at the base of the pipes. There were also considerable differences along the length of individual parts of pipes. When plotted on a Gumbel plot for the maximum pit depths, the deepest pits showed a different Gumbel trend compared with the majority of pit depth maxima. Theoretically, this indicates that different pitting mechanisms are involved. This possibility is explored by reference to earlier work on the long-term pitting corrosion of steels in sea water. Comments are made also about empirical fitting with other extreme value distributions, as sometimes suggested.

Simple Way of Predicting the Corrosion Inhibitors Efficiency of Carbon Steel in Seawater

Simple Way of Predicting the Corrosion Inhibitors Efficiency of Carbon Steel in Seawater

천연 해수에서 304 스테인리스강의 내식성에 미치는 DC glow 방전 플라즈마 이온질화처리 온도의 영향

천연 해수에서 304 스테인리스강의 내식성에 미치는 DC glow 방전 플라즈마 이온질화처리 온도의 영향

Electrodeposition and Corrosion Resistance of Cu/Zn/Cu Multilayer Coatings

Cu/Zn/Cu multilayer coatings were prepared on mild steel substrates by dual bath technique in order to improve the corrosion resistance of mild steel in seawater. The microstructures of the coated substrates and its resistance to corrosion in simulated seawater were evaluated by scanning electron microscopy (SEM), the brine immersion test and electrochemical impedance spectroscopy (EIS). Salt water immersion test results show that the Cu/Zn/Cu multilayer coatings exhibited the highest corrosion resistance. The red rust spot appeared on the coating surface for the first time when the time of the coating soaked in salt water reached 2520h. The trend of the impedance variation reflected by the electrochemical impedance spectroscopy was the same as the change tendency of corrosion resistance was analyzed by the salt water immersion test. The results of SEM showed that the layer of copper were deposited by round cell structure, the middle layer of zinc coating was flat and compact.

Effect of Bacillus Vietnamensis as an Iron Oxidizing Bacterium on Corrosion of 2507 Duplex Stainless Steel in Sea Water

Effect of Bacillus Vietnamensis as an Iron Oxidizing Bacterium on Corrosion of 2507 Duplex Stainless Steel in Sea Water

Synergistic protective effect of carboxymethyl chitosan and cathodic protection of X70 pipeline steel in seawater

This study has investigated corrosion inhibition performance on X70 pipeline steel in seawater using carboxymethyl chitosan (CMCS) and Na2WO4 at a cathodic protection potential of −0.85 V (vs. SCE).

Study of Pitting Resistance of Rebar Steels in Jakarta Coastal Using Simulated Concrete Pore Solution

Carbon steels are generally used to a reinforcement in the concrete constructions, such as bridges, piling, etc. These constructions are not a bit placed in the coastal areas, especially the coastal area of Jakarta. The industrial activities and urban development were a source of sediment loads and pollutants in coastal sea water Jakarta. The presence of chloride content and pollutants in sea water could affect the process of corrosion of reinforcement steel in concrete especially pitting corrosion. In this paper, the behavior of pitting corrosion of reinforcement steel in sea water of Jakarta coastal using simulated concrete pore solution has been studied. The sea waters were taken from two different locations of Jakarta coastal, Ancol beach and Muara Baru fishing port. Each of the sea water was used as a solvent in the simulated concrete pore solution with or without carbonates. The simulated concrete pore solution with chloride was also utilized for comparison test. The cyclic and potentiostatic electrochemical polarization were conducted to evaluate the behavior of pitting corrosion of reinforcing steel. The experimental results showed that the reinforcing steel was susceptible to pitting corrosion in the simulated concrete pore solutions (SPS) of sea water with or without carbonates and in the simulated concrete pore solutions containing 3.5% NaCl. The addition of sodium carbonate and sodium bicarbonate in SPS of sea water increased the breakdown potential value and the total time for the metastable pitting decreased slightly.

Onset of Microbial Influenced Corrosion (MIC) in Stainless Steel Exposed to Mixed Species Biofilms from Equatorial Seawater

The understanding of microbial influenced corrosion (MIC) in aerobic mixed biofilms benefits from advanced microscopy and microbial ecology characterization of biofilms. Here, the onset of MIC in stainless steel coupons was studied in both natural and artificial seawater. Rapid selection of biofilm-forming microorganisms from natural seawater was observed for field experiments. Potential ennoblement was observed only in natural seawater. A seawater derived mixed microbial consortium enriched in artificial seawater was used to characterize the effect of several parameters on MIC. The concentration of organic carbon was the major determinant of MIC, while shaking speed and polishing played minor roles. The biofilm was preferentially formed at the grain boundaries. These results outline the need for MIC onset characterization with mixed microbial consortia to predict long-term corrosion behavior of stainless steel in seawater.

The growth mechanism of calcareous deposits under various hydrostatic pressures during the cathodic protection of carbon steel in seawater

Ca2+ was substituted by Mg2+ in CaCO3 crystallization under high pressure resulting in a crystal transformation from aragonite to dolomite.

Effect of strain-induced martensite on the tribocorrosion of AISI 316L austenitic stainless steel in seawater

Pin-on-disc friction experiments were carried out to investigate the tribocorrosion of AISI 316L in seawater, demonstrated that the tribocorrosion of AISI 316L was dominated by the formation and corrosion of strain-induced-martensite with austenite.

Can Thermally Sprayed Aluminum (TSA) Mitigate Corrosion of Carbon Steel in Carbon Capture and Storage (CCS) Environments?

Transport of CO2 for carbon capture and storage (CCS) uses low-cost carbon steel pipelines owing to their negligible corrosion rates in dry CO2. However, in the presence of liquid water, CO2 forms corrosive carbonic acid. In order to mitigate wet CO2 corrosion, use of expensive corrosion-resistant alloys is recommended; however, the increased cost makes such selection economically unfeasible; hence, new corrosion mitigation methods are sought. One such method is the use of thermally sprayed aluminum (TSA), which has been used to mitigate corrosion of carbon steel in seawater, but there are concerns regarding its suitability in CO2-containing solutions. A 30-day test was carried out during which carbon steel specimens arc-sprayed with aluminum were immersed in deionized water at ambient temperature bubbled with 0.1 MPa CO2. The acidity (pH) and potential were continuously monitored, and the amount of dissolved Al3+ ions was measured after completion of the test. Some dissolution of TSA occurred in the test solution leading to nominal loss in coating thickness. Potential measurements revealed that polarity reversal occurs during the initial stages of exposure which could lead to preferential dissolution of carbon steel in the case of coating damage. Thus, one needs to be careful while using TSA in CCS environments.

Synergistic damage mechanism of corrosion and cavitation-erosion for plasma ion nitrided 18Cr–8Ni–1.1Mn–0.43C stainless steel in seawater

In this work, it was investigated that resistance of combination damages of electrochemical corrosion and cavitation-erosion for plasma ion nitrided 18Cr–8Ni–1.1Mn–0.43C stainless steel at various process temperatures under cavitation environment in seawater. The plasma ion nitriding treatment was performed with a gas mixture ratio of 25% N2 and 75% H2 at a temperature of 623, 673, 723, and 773 K for 10 h, at a chamber pressure of 250 Pa. Expanded austenite (γN) was produced at whole plasma ion nitriding temperatures and especially phases of CrN and γ′ were observed at 773 K in X-ray diffraction (XRD) analysis. In Tafel analysis, the highest corrosion potential and corrosion current density were analyzed on the untreated (non-cavitation) specimen among specimens under the cavitation condition. Under cavitation environment, the highest corrosion potential and the lowest corrosion current density presented at 673 K. As a result of observation of surface morphologies after anodic polarization experiment under cavitation environment, uniform corrosion was observed on the untreated specimen and plasma ion nitrided specimens, while localized corrosion was shown on the untreated substrate under non-cavitation environment. Furthermore, greater damage depth and severe morphologies were observed at plasma ion nitrided specimens than untreated substrate, whereas the greatest weight loss at 723 K was indicated due to the high pitting corrosion potential and wide passivity potential region.