Marine and off-shore components including propellers, pumps, valves, pipelines and other submerged surfaces are subjected to severe degradation by erosion-corrosion phenomenon. Amongst others, surface coatings are widely recognized as a promising way to dealt with such degradation problems. One of the most widely used techniques for developing coatings is thermal spraying. However, the inherent lamellar microstructure of thermal sprayed coatings and presence of splat boundaries, pores and un-melted particles results in anisotropic behavior together with poor mechanical and tribological properties. Erosion-corrosion phenomenon depends significantly on the microstructure of the target surface. Therefore, efforts on homogenizing the microstructure will likely improve the durability of components subjected to erosion-corrosion environment. The aim of the proposed work is to utilize different post-processing techniques with an objective to address the above listed issues by systematically evaluating the influence of these techniques and enhance the performance of thermal spray coatings.
The proposal on post-processing of coatings aims to develop superior coatings for marine components which are typically subjected to erosion, corrosion as well as erosion-corrosion environment. Coatings are economical alternative for improving the tribological properties of materials. However, the inherent lamellar microstructure of thermal sprayed coatings and presence of splat boundaries, pores and un-melted particles results in anisotropic behavior together with poor mechanical and tribological properties. The study includes development of some novel coating compositions followed by their postprocessing using different techniques including microwave sintering, high strain deformation and heat treatment. This will be useful to develop fundamental understanding on the influence of key parameters on the microstructural refinement, mechanical properties as well as structure-property relation of coatings, which is still not well understood.