Improved Protection of Magnesium Alloys Against Synthetic Aviation Lubricants at Elevated Temperatures

Magnesium alloys axe widely specified for aero-engine lubrication system casings because of their inherent lightweight. Advances in engine design and performance have increased lubricant temperatures to the point that magnesium corrosion can occur due to reaction with the hot oil.

Work, carried out under Ministry of Defence contract has shown that Dow 17 anodic pretreatment of magnesium provided superior protection against hot lubricant attack compared to HAE anodic and chromate conversion coatings. Sealing the Dow 17 film with suitable epoxy or phenolic resins provided protection up to 200°C. Protection up to 225°C was obtained using a polyimide resin as the sealer.