Repair of Corrosion Pitting on Al Alloy By Selective Plating of Zinc-Nickel Alloy

The repair technique is based upon the well known brush plating process, for which DALIC has been the pioneer in France.  Nickel was first deposited on the edge of the slat, the most deeply damaged area, to reestablish the initial profile.  This was followed by an anti-corrosion layer of zinc-nickel alloy.  The coating was so efficient that painting and passivation were no longer required.  The presented application results from the qualification by the French Ministry of Defense & Dassault Aviation of a repair solution for wing slats of Coast Guard aircraft of the French Navy.  The slats, exposed to hard marine conditions, faced corrosion pitting and erosion by coral sand, and they had to be replaced frequently.  The solution was validated by thermal shock, corrosion, fatigue, and in flight testing.