Study on Developments in Protection Coating Techniques for Steel

Abstract

Steel, also known as iron alloy, is found 35% of the whole mass of the Earth. It is found in many applications due to its unique properties. Alloying elements provide the backbone support for iron, improving its mechanical, physical, chemical, and structural properties. Failure of steel is due to chemical reaction i.e., corrosion, and it is unavoidable, but it can be prolonged. Applications such as marine have a salt corrosive environment. High-temperature applications such as power plants, gas turbines components, and combustion engine components accelerate air oxidization at higher temperatures. Protection coating alters the chemical composition of alloy surfaces by using techniques like conversion coating, mechanical alloying, ion beam implantation, laser cladding, and thermochemical treatments. Protection coatings adhere to the steel surface and prevent steel from direct contact with the environment, which is formed by chemical vapor deposition, physical vapor deposition, electroplating, chemical bath, sol-gel, thermal spraying, and hot-dip coating. These coatings are used to reduce the chemical reaction in accelerated corrosion environments so that the life span of the steel is further enhanced, thereby decreasing the replacement cost. These coating methods and coating materials play a vital role in corrosion and other corrosion-associated failure protection. The coating materials like chromium and cadmium produce carcinogenic gases. Coating methods such as thermal spraying, hot-dip coating, and thermochemical treatment produce by-products that affect the environment by releasing pollutants. It is essential to choose coating materials and methods that do not influence the environment and ecosystem. In this work, processing techniques available to prepare the protective coating for steel are discussed. The methods used to enhance the properties of steel and the various real-time characterizations are also discussed. In addition, challenges and opportunities in the proposed scope are also included.