Electroplated Alloys for Replacement of Hard Chrome on Stainless Steel Actuators

ABSTRACT: Electrolytic Hard Chrome (ECH) is the standard coating method for 4XXX steels used in actuators and depot-based repair of damaged items. The properties of EHC coatings are excellent, and as a result EHC coatings have been used for more than 50 years. Unfortunately, EHC plating uses hexavalent chromium (Cr6+) that is regulated by both OSHA and the EPA. Health and environmental concerns with hexavalent chromium has led the DOD to direct the military to develop chromate substitutes in plating operations. There are several hidden benefits of EHC coatings, including the presence of numerous existing plating facilities (both OEM and repair depots) and a large cadre of skilled plating personnel. Thus an attractive replacement for EHC coatings on 4XXX steel actuators would be an alternative plating approach that provides a hard coating that is ductile, lubricious and corrosion resistant and that gives the same or better performance than EHC, and can be applied with existing facilities and by personnel, but which does not involve the use of toxic plating solutions. The Phase I effort will evaluate electroplated ternary alloy compositions that have the desired properties and can be plated from aqueous baths using low-toxicity electroactive metal salts. BENEFIT: The proposed work will identify a high performance electrodeposited alloy that can replace EHC coatings. The new material will have better performance than EHC coatings thereby leading to longer lifecycles and lower costs, and the mew electrodeposited alloys will be plated from non-toxic plating baths that will support the move from hexavalent chromates to greener materials.