Applications for Chrome Plating Alternatives: Repair Technology and OEM Coatings

摘要

This paper describes the Hard Chrome Alternatives Team (HCAT) program, a tri-service effort to replace hard chrome in the DoD environment of OEMs and bases. The primary applications arc in repair/rebuilding of worn parts, and in applying wear resistant surfaces to certain original parts, such as hydraulics. Since prior work has demonstrated the value of High Velocity Oxygen Fuel (HVOF) thermal spra and vacuum Physical Vapor Deposition (PVD) coatings for different applications, the HCAT program is concerned with transferring these technologies to DoD maintenance shops and DoD contractors. While PVD coatings are ideal for relatively small components at the OEM level. HVOF coatings are needed for rebuilding and for application to large components such as aircraft landing gear. The program will incorporate several HVOF coatings, including WC-Co and Tribaloy. and PVD coatings, including CrN and TiN These coatings will be evaluated on commonly used alloys and demonstrated on specific components and classes of components made from them. The paper discusses the various aspects of what is required of a chrome replacement if it is to be suitable for use in the DoD environment. Not only must it provide the necessary wear resistance, but it must fit properly with the entire environment that it will see during its life, including original application, use. and maintenance The HCAT program is designed to gather all the information needed to properly define the coatings and permit their approval on flight-critical components. Demonstrating and validating chrome alternatives will include all the stakeholders, from the final approval agencies to the process engineers who apply to coatings from day to day. The program is designed so that it will demonstrate and validate several alternatives, and provide both OEMs and repair depots with the capability of using them on a production basis.