Advanced Coating to Mitigate Hydrogen Embrittlement in High Temperature Environments

The failure of metallic parts due to hydrogen embrittlement has been a constant challenge for many industries for decades, and for NASA in particular. The hydrogen embrittlement problems endemic to industries that require heavy use of hydrogen have been solved in various ways. Most of these solutions involve the careful development of alloys that are less susceptible to hydrogen embrittlement. Unfortunately, these alloys often require a sacrifice of some other highly desired material property, such as strength, hardness, ductility, etc. Coatings have also been attempted. However, these coatings and coating techniques have their own drawbacks, which include ceramic coatings that flake off after only a few use cycles and coating techniques that cannot deposit onto a finished part because they require line of sight during deposition. To better mitigate the very pressing hydrogen embrittlement challenge, Summit Information Solutions, Inc. proposes the use of a mature deposition technique that has not seen much use outside of the microelectronics industry. A thin film encapsulate will be deposited onto test samples of Inconel 718 and A-286 austenitic stainless steel. The coating material has a melting temperature in excess of 5500 °C, and is non-reactive with hydrogen. The coated samples’ properties will be tested, and the results will be compared to those of the untreated samples. Summit’s goal for Phase I is to show that the surface treatment is a robust layer at elevated temperatures. The extensive hydrogen embrittlement tests will be conducted in Phase II of the project.