Improved corrosion resistance of thermally sprayed coating via surface grinding and electroplating techniques

Electroplating of Ni is one of the popular and well-studied surface engineering techniques used for corrosion protection in many industries. The equipment setup is cost-effective, simple and readily available to industries. This work explored the novel application of such electroplating technique to seal the porous surface of thermally sprayed coatings, with an aim to enhance the coating's ability to resist chemical corrosions further. The investigation employed a potentiostat as a testing method to study the corrosion behaviors of thermally sprayed samples, both plated and non-plated with Ni. The results can be summarized that the Ni plating of a few microns thick can successfully seal the arc-sprayed coatings of Hastelloy C-276. The plating layers provide a good corrosion protection for the underlying coatings. The corrosion behavior can be improved further by smoothening of the coating surface prior to the plating process. These encouraging findings will lead to the development of a sealing technique for the thermally sprayed coatings in order to enhance the corrosion resistance of the coatings and extend the limits of the coatings to more severe applications.