Because of its hardness, dimensional tolerance and resistance to hydrogen, cadmium plating has been used to protect steel components in marine environments. However, Cadmium is thought to be toxic and a search is on for an alternative. In this paper, cadmium and zinc-nickel plating/coating were compared in water immersion, temperature cycling, rain, humidity, and salt fog testing.
Field experience was studied to identify the best solutions to Localized corrosion of 316 stainless steel instrument and chemical injection tubing in marine environment. Laboratory tests and exposure in marine environment of samples have been used to evaluate possible alternative materials and protective chemicals.
In this work, the open circuit potential of different stainless steel grades as well as nickel based and copper based alloys has been systematically measured in seawater under different experimental conditions. In particular the effect of temperature, oxygen content and chlorination level have been studied.
Requirements for corrosion protection for new large offshore wind farms are extended to 25 years’ maintenance-free service lifetime. Therefore, ISO 12944 is being updated. To bring down construction cost for offshore wind, initiatives have been taken to industrialize the coating application process and use standard components.
Electrochemical test methods including open-circuit potential, electrochemical impedance spectroscopy, potentiodynamic polarization, and zero-resistance ammetry were used for corrosion investigation of UNS C69100 in a 3.5 wt.% sodium chloride aqueous solution, with optical and scanning electron microscopy.
An experimental protocol including in situ potentiostat and quasi-static tensile tests to provide an improved understanding of the corrosion behavior of UNS G10210 steel. A local-global finite element method has been proposed to model a steel plate at a ship compartment scale under uniaxial quasi-static tensile/compressive loading.
Differences between temperate and tropical sites in terms of electrochemical behavior (e.g. open-circuit potential and cathodic current for oxygen reduction). One difference is critical temperature for biofilm ennoblement. Results are discussed in terms of risk for crevice corrosion for stainless steels in tropical seas.
Chloride induced corrosion is the prime reason for the degradation of embedded rebar in reinforced concrete marine structures. The present study experimentally investigates the effectiveness of traditional two-component epoxy (EPX), and moisture-cure polyurethane coatings (MC) applied on the concrete surface in reducing the rate of chloride ingression compared to the conventional concrete with and without mineral admixtures like fly ash and GGBS. Coatings used in the present study are characterized by XRD, EDAX, FEG-SEM, water uptake, adhesion strength and contact angle tests. Rapid chloride migration tests (RCMT) were conducted on concrete with and without coatings. Resistivity offered against the chloride migration monitored during the RCMT test indicated that concrete with MC shown higher resistivity in the initial period and continued to decrease over the test duration at a faster rate, unlike EPX. The non-steady-state migration coefficients of the concrete cured for 28days and coated with MC and EPX coatings were found to be nearly 22% and 48% of that of concrete with SCM cured for 84days respectively. The study is further extended to monitor the corrosion of rebar embedded in coated concrete subjected to corrosion acceleration until the first crack appeared on an uncoated specimen. Variation in current flow, half-cell potentials recorded during the acceleration test and actual mass loss of embedded rebar estimated by gravimetric analysis are presented in this paper.
CP coupons have been used since the 1930s by several of the pioneers of the corrosion-control industry, both in North America and in Europe. Over the last two decades, the use of CP coupons has been rediscovered as a practical method to determine the level of polarization of a buried structure and to confirm the voltage drop in a potential measurement. Acceptance of CP coupon technology is slowly occurring. Research sponsored by the pipeline industry has explored the use of CP coupons and has helped validate the use of this technology.