Functionally Graded Aluminum Nitride - Oxide Coatings for Hot Pipe Protection

75080-Ferrous metals are prone to hot corrosion or high-temperature oxidation under conditions found in power plant piping, heat treatment, aerospace propulsion, and other extreme environments. Alumina-based coatings would provide substantial oxidation resistance to ferrous alloys without the cost of exotic alloys, thereby increasing production efficiencies in numerous industries. This project will develop and produce a functionally graded aluminum nitride/aluminum oxide coating for ferrous alloys and the coated material will be tested for high-temperature oxidation resistance. In Phase I, a room-temperature molten salt reaction will be used to produce a volatile precursor compound that can be converted to aluminum nitride by in situ reactive deposition. The aluminum nitride will then undergo controlled oxidation to form a graded aluminum nitride/oxide coating. The aluminum nitride will adhere well to the ferrous substrate, and the aluminum oxide will provide high temperature oxidation resistance. Commercial Applications and Other Benefits as described by the awardee: The petrochemical, power generation, military, and paper industries are keenly interested in new methods for reducing hot corrosion and thermal oxidation of ferrous alloys. High performance coatings from this innovative source would provide significant cost savings to those industries.