Abstract
Aluminium and its alloys are widely used in a wide variety of applications. Aluminium's main advantages include: lightness, high specific strength, high thermal and electrical conductivities, good formability, excellent machinability, diversity of aluminium alloys, extensive range of forming and processing options (e.g. rolling, extrusions, stampings, forgings and castings) and suitability for a diverse range of joining techniques, surface treatments and recyclability. A number of surface treatment technologies are available which produce thicker oxide coating layers that can be used to combat corrosion and wear of aluminium alloys under aggressive environments, such as in petroleum extraction environments. Coating processes for surface modification of aluminium alloys include plasma electrolytic oxidation, plasma-sprayed ceramic and hard anodising. In this article, erosive wear characteristics of coatings produced using the aforesaid three processes are compared with each other and benchmarked against the uncoated aluminium substrate. This article investigates the extent of erosion resistance, in particular impingement due to sand loading, of these coatings taking into consideration the effect of material properties such as adhesion, ductility and roughness.