The role of natural materials in enhancement or prevention of corrosion in a harsh marine environment

This thesis studies the impact, on a painted surface, of the presence of some natural oils (olive, mustard, and fish oil) and proteinaceous substances derived from ground insects and eggs. The performance of both water-based and oil-based coatings has been tested in a series of experiments. These were designed on the basis of a literature review and current practices regarding corrosion inhibition. Laboratory tests were done in a simulated marine environment and an acidic environment according to ASTM standards. A marine corrosion environment was simulated in a corrosion or salt fog chamber. For all samples, the nature of corrosion and the extent of growth were observed against a control, testing under the same conditions and the same time period. Various parameters such as surface roughness, weight, and pit growth on the sample surface were measured for each sample after exposure periods of 1000, 2000, and 3000 hours in the salt fog chamber. A low pH environment was simulated in an immersion chamber. The samples were checked for blistering effect, on the surface, according to the ASTM photographic reference. (Abstract shortened by UMI.)...