Evaluation of Mechanical Properties on Ni–Cr Alloy-Coated Marine Structures

Abstract

Surface coating has been used in abundance of engineering applications and components to protect and strengthen the surface of the material from corrosion which damages because of some atmospheric conditions and enhance their span of materials life. Corrosion or abrasion is caused naturally in which the materials destruct gradually using electrochemical or chemical reaction with their environment. This corrosion in metals occurs mainly due to air, water, and other environmental aspects. Steel structures have been used in many years of marine structural applications due to high fatigue strength, higher tensile strength, excellent dimensional stability, and thermal conductivity. The marine structure gets corroded due to the sea water and atmospheric conditions. The marine structures are made up of low carbon steel with various thickness from 6 to 20 mm, depends on the marine applications. The low carbon steel easily corrodes, so that the paint coating on the low carbon steel is in existence. This paint-coated surface directly reacts with marine atmosphere and forms a rust layer between 6 and 12 months. To prevent this rust layer formation, we need to bond coat with excellent corrosive resistive material under marine environment. These structures were partially immersed and floating in sea water. In fishing mechanized boat, the marine hull corrodes quickly due to marine atmosphere and heat lost from the engine room. This work focuses on protecting the marine structure subjected to corrosion and improving the mechanical strength and lifespan of marine structures with microparticle coating on the marine hull surface. The Ni–Cr powder coating was layered on the low carbon steel structure using plasma spray coating techniques with thickness of 100 and 150 µm. These prepared specimens was sized according to ASTM standards to perform the mechanical properties such as tensile, flexural and impact testing, and hardness tests like Rockwell, Brinell, Vickers, etc. The morphological structure also studied using SEM. The results show that the utilization of Ni–Cr micro-particle coating improves the mechanical strength of the mechanized boat hull from the paint coating in existence. The result reveals that coating improves the mechanical strength as well as its lifespan.