Formation of composite layer by nanocoating of organic and filler of inorganic compounds on mild steel to control in chloride ions environment

Abstract

Mild steel is used in marine water and marine atmosphere for various applications. Marine is highly saline so Cl ions concentration is more which develop corrosive environment for mild steel. Polymeric coating can be applied on the surface of base metal for their mitigation. This coating cannot provide good protection in long duration. Polymeric-coated mild steel surface has lots of porosities so Cl-ions easily enter inside and produce corrosion cell. Cl ions produce disbonding between base metal and polymeric materials. It accelerates corrosion reaction and metal exhibits galvanic, pitting, stress and crevice corrosion. Cl ions produce chemical reaction with coated polymer and starts decomposition. Marine air Cl ions component is rich so it creates hostile environment for other materials. Nanocoating and filler methods are applied to mitigate the corrosion of mild steel marine water. For this work synthesized octahydrodibenzo[a, d][8] annulene-5, 12diphenylhydrazone and that compound was coated on the surface polymeric-coated mild steel and their porosities were blocked by CoS filler. Nanocoating and filler compounds were formed composite barrier on mild steel surface which control the effect of Cl ions. The coating work was completed by nozzle spray. The corrosion rate was determined by weight loss experiment and corrosion current density was calculated by potentiostat techniques. The composite barrier formation was studied by activation energy, heat of adsorption, free energy, enthalpy and entropy. The surface coverage area and coating efficiency were indicated that nanocoating and filler compounds were mitigated corrosion of mild steel in Cl ions environments.