Pulsed plasma electrolytic oxidation processes for aeronautical applications and their technical application

A range of aluminium alloys have been treated by plasma electrolytic oxidation in different alkaline electrolytes containing silicate, aluminate, vanadate and other additives, under pulsed current conditions and the dependence of oxide thickness growth rates on variation in electrolyte and operating conditions measured. The oxide morphology was examined by SEM, and coating phase and crystal size analysis was carried out by XRD. Coating hardness varied with anodising current type and electrolyte composition, and the incorporation of dispersed nano silica particles.