Electrochemical Behavior of Metallic Coatings Containing Carbonaceous Additives

Abstract

It has been shown recently that incorporation of carbonaceous additives such as graphene, graphene oxide, and carbon nanotubes (CNTs) into conventional metallic coatings produces composite coatings with significantly enhanced corrosion resistance behavior. It is believed that the observed enhancement in the newlinecorrosion resistance is essentially due to the stability and impermeability of graphene/graphene oxide (GO) and hydrophobicity of the CNTs. In this thesis, it is shown that in addition to the above factors, microstructural alterationsof the metallic coatings caused due to the incorporation of carbonaceous additives newlinealso play a major role in deciding the corrosion properties of the coatings. The electrodeposited systems that have been explored in the present work are: NiCo-graphene oxide, NiCo-carbon nanotube, ZnCo- graphene oxide, ZnCo-carbon nanotube, and ZnMn-graphene oxide composite coatings. In allthe cases, the corrosion rate was found to be very sensitive to the amount of additive present inthe coatings. With increasing GO/CNT content, the corrosion rate first decreased to a minimumvalue followed by sudden increase to values higher newlinethan the pristine coating. newline