HVOF Thermal Spray Technology as a Replacement for Hard Chrome Plating in the Aerospace Sector
Mr. Bruce D. Sartwell1 and Dr. Keith O. Legg2, 1Battelle, c/o Naval Research Lab (Code 6170), 4555 Overlook Ave SW, Washington, DC 20375, 2Rowan Technology Group, 1590 S. Milwaukee Ave, Suite 205, Libertyville, IL 60048

The U.S. Hard Chrome Alternatives Team (HCAT) has executed and is currently executing projects to qualify HVOF thermal spray coatings (principally WC/17Co and WC/10Co4Cr) as a technologically superior, cost-effective alternative to electrolytic hard chromium (EHC) plating which is widely used in manufacturing and repair of aircraft components.  Because of the extensive use of EHC on aircraft, separate projects were established for different categories of aircraft components.  At present, three projects have been completed: landing gear, propeller hubs and gas turbine engine components.  The status of implementation of the HVOF technology on new advanced aircraft such as the Joint Striker Fighter and at repair depots in these areas will be reviewed.  Recent results on materials testing related to the other two projects on hydraulic actuators and helicopter dynamic components will be presented.  The materials tests required for qualification of the HVOF coatings were developed through consultation with stakeholders and preparation of joint test protocols.  General types of materials testing have included axial fatigue, salt-fog corrosion and sliding wear against mating materials normally used in service.  As part of the execution of the projects, standards and specifications for deposition, grinding, and stripping of the thermal spray coatings were developed and they have been issued by the SAE Aerospace Materials Engineering Committee.  In addition, cost/benefit analyses for implementation of the HVOF coatings to replace EHC plating at repair/overhaul facilities have been performed, which generally show a positive return-on-investment when viewed over an extended period of time.

Session 17: Thermal Spray & Other Surface Engineering Technologies 3

The Preliminary Program for International Thermal Spray Conference And Exposition (ITSC) (May 15-18, 2006)