An investigation of the corrosion behaviour of a range of engineering materials in marine environments
This work represents an investigation of the corrosion behaviour of primarily high-grade alloys in marine environments. A range of marine conditions of varying severity has been considered and their effect on the electrochemical corrosion characteristics assessed. The study has utilised a range of electrochemical monitoring techniques, light and scanning electro microscopy and other surface techniques to assess the extent and morphology of corrosion attack under certain conditions. Principal components of the study include the effect of elevated temperature (up to 60oC) on corrosion initiation and propagation in static and high velocity impinging seawater. In addition, the effect of micro and macro fouling has been assessed using immersion tests and a hydrodynamic model. Continuation of the biological effects on corrosion looked at the effect of the presence and activity of Sulphate Reducing Bacteria (SRB) on corrosion mechanism. Correlations between accelerated laboratory tests and the real time behaviour of materials have been successfully made. Methods to counteract fouling often include the use of biocides and, in this study, the effect of high levels of hypochlorite dosing has been investigated. Mechanical and corrosion effects by liquid impact and by liquid-solid impact constitute a major part of this work and the use of electrochemical tests has enabled the proportions of weight loss on a given material attributed to corrosion, erosion and a synergistic factor to be elucidated. Several options exist to combat excessive deterioration due to mechanical wear. Two processes, shot-peening and laser irradiation, have been assessed primarily for corrosion resistance in a marine environment.