Red Mud - Fly ash Composite Coating on Metal Subotrates

Abstract

Thermal spraying in plasma environment is a versatile surface technique, which has the advantage of being able to deposit metals, ceramics and or a combination of these, generating homogeneous coating of desired microstructures. The surface coatings help in protecting against corrosion and may act as insulating barriers. In the present work, two abundant industrial wastes viz. red mud (the waste generated in alumina plants) and fly ash ( waste from thermal power plants) are taken, mixed in a definite proportion and the mixture was spray coated on aluminium , copper, mild steel and stainless steel substrates. Coatings were made at different operating power levels of the plasma torch. It is observed that the quality and structure of the coating are greatly affected by the input power to the torch. The substrate- coating interface bonding strengths for different samples were found out by pullout method. Coating-substrate interface morphology is studied by scanning electron microscopy. Potential areas of application are suggested.