Replacement of Chromium Electroplating on Gas Turbine Engine Components Using Thermal Spray Coatings
Abstract
Hard chromium electroplating is extensively used by aircraft manufacturers and military maintenance depots to provide wear and/or corrosion resistance or to restore dimensional tolerance to components. However, chrome plating utilizes hexavalent chromium, which is a highly toxic carcinogen, and increasingly, stringent environmental and worker-safety regulations are making chrome plating more expensive for the DoD. This document constitutes the final report on a project to qualify high-velocity oxygen-fuel (HVOF) and plasma thermal spray coatings as a replacement for hard chrome plating on gas turbine engine components. Extensive fatigue, fretting wear, salt-fog corrosion, and carbon-seal wear tests were performed on HVOF, WC/17Co, Tribaloy 400, Tribaloy 800, and Cr3C2/20(NiCr), and plasma-sprayed Tribaloy 400 coatings compared to hard chromium. In general, the HVOF WC/17Co coatings demonstrated superior performance. An accelerated test on a TF33 engine containing seven components coated with HVOF WC/17Co showed superior performance to what would have been expected using the standard hard chromium. A cost/benefit analysis indicates that military repair depots that overhaul gas turbine engines can realize substantial savings by converting from hard chrome to HVOF.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 20, 2005
- Accession Number
- ADA436106
Entities
People
- Anne Kaltenhauser
- Bob Bondaruk
- Bruce D. Sartwell
- Charles Alford
- Gary Shubert
- Jerry Schell
- Keith O. Legg
- Paul Natishan
- Philip Bretz
- Steven Lawrence
Organizations
- United States Naval Research Laboratory