Challenges in oxidation resistant coatings

Abstract

Degradation of materials at high temperatures is a major concern in many sectors, including power generation, refinery and petrochemicals, chemical processing, metallurgical processing, paper and pulp, automotive, aerospace and defence. This degradation manifests itself mainly as oxidation, although solid particle erosion, phase transformation, hot corrosion, spalling of surface oxides and volatilisation are also encountered. Materials exposed to industrial atmospheres must be resistant to attack by the environment, and if the component is load bearing also to deformation. For many such components it is possible to choose a material with a suitable combination of properties. However, as mechanical loads and the severity of attack increase, the range of materials with an acceptable combination of properties becomes more limited. A solution to this problem is to design the material such that the surface is optimised to resist attack by the environment and the bulk is optimised to bear the mechanical load.Coatings are widely used to protect metallic components and are ideally specified to ensure the component is capable of operating efficiently throughout its design life. Oxidation resistant coatings are generally metallic or ceramic and should: