B. Deeken, Goodrich Aerospace Landing Gear Division, Cleveland, OH; K. H. Donaldson, AlumiPlate, Inc., Minneapolis, MN

Summary:

In the world of surface finishing engineering there is always a need for new innovations in corrosion coatings. The wide variety of applications requirements makes it difficult to find one coating that will meet all (or even most) needs. While there are a large number of surface coatings and treatments commercially available that offer adequate corrosion protection in many applications, there are specialty areas in the aerospace industry such as landing gear where the traditional suite of alternatives offer less than optimum solutions. New coatings are constantly being sought for improvement over previous compromise solutions, as well as to accommodate industry, environmental, or regulatory changes that occur from time to time. One such change that is affecting the aerospace industry is the ever-increasing regulatory and environmental pressure for the elimination of cadmium ¹. Electroplated high purity aluminum is rapidly becoming established as an ideal cadmium replacement coating for the prevention of corrosion of military aerospace designs. Electroplated aluminum is non toxic and non hazardous to the environment and eliminates the concerns for handling and disposal that exist in cadmium. AlumiPlate® electroplated aluminum has been adopted, or is undergoing verification testing, by several of the largest U.S. aerospace companies, particularly with a focus on landing gear components and electrical connectors, and is gaining momentum as the coating of choice in difficult military environments. This presentation will give an overview of AlumiPlate’s technology and process as well as technical performance status specific to aircraft landing gear engineering applications. A series of qualification tests and results will be discussed. These include; corrosion, adhesion, fatigue, and hydrogen embrittlement. Based on these test results, AlumiPlate is now considered the leading surface finishing choice as a cadmium alternative for the F-35 Joint Strike Fighter program.

¹Metals Processing & Materials 40 CFR 438, final rule effective December 2002, substantially lowers the allowable limits of Cr, Cd, Zn, Ni and Sn in effluent water during fabrication or maintenance of aircraft. The Directive of the Council of European Communities COM (97) 358 calls for the elimination of Cd, Hexavalent Cr, Hg and Pb in transportation equipment.