Non-Toxic, Corrosion-Resistant Amorphous Coatings for Protection of Steel Tailhook Components

The U.S. Navy desires the replacement of cadmium (Cd) platings for the protection of high-strength 4330V steel employed in arresting-gear tailhook components. While Cd is a protective coating, it is not environmentally-friendly. As an alternative, Engineered Coatings (ECI) and Southwest Research Institute (SwRI) propose a two-tier approach: 1) higher-risk atmospheric-plasma chemical vapor deposition of amorphous Al-alloy coatings (ECI) and 2) lower-risk ion-beam assisted deposition (IBAD) of amorphous Al-alloy coatings (SwRI). The higher risk approach is a non-vacuum process, which simplifies component handling, while the second process has produced coatings with improved corrosion protection over pure Alcad surfaces on Al, Ti, and steel surfaces. Both processes are inherently non-toxic, as vapor-phase and gaseous effluents are generated for the AP-CVD process and solid particulate waste is generated for the IBAD process. Our team proposes to develop processing parameters to deposit thick amorphous Al-alloy coatings and perform a systematic testing protocol, using a subset of the recommended Boeing/CTC test protocol for steel landing gear components. This will include composition/structure determination, bend-adhesion, salt-fog exposures, and galvanic-coupling measurements. In the Phase I option, we will develop fixturing and translation methods to enable uniform coverage of the complex tailhook geometry and develop a preliminary M&P specification.