Review of inorganic coatings and coating processes for reducing wear and corrosion

Advances in materials performance often require the development of composite systems, of which coated materials are one form. The abrasion and corrosion resistance of components can be greatly increased by protective coatings and this is a growing industry of considerable economic importance. Coatings are used in both aqueous and high temperature applications. Coal gasification, electric power generation, and waste incineration involve severe conditions and thick coatings have proved effective. Diesel and gas turbine engines are subject to high temperature corrosion and highly beneficial coatings have been developed. Some nuclear power systems also rely on coatings. Factors that must be taken into account include substrate compatibility, adhesion, porosity, the possibility of repair or recoating, interdiffusion, the effect of thermal cycling, resistance to wear and corrosion, and cost. This review of alternative systems emphasises the necessity for the coating and substrate to be designed as an integrated whole, bearing all of these considerations in mind.