Kinetic Metallization of Corrosion Resistant Coatings for Molten Salt Heat Exchanger Components on NGNP(IV)

Next Generation Nuclear Plants (NPNG), which are expected to be based on Advanced Gas Cooled Reactor (Generation IV) technology, will require molten-salt heat-exchanger subsystems, which operate at very high temperatures (>900°C), for hydrogen production. Development of improved high-temperature metallic alloys and coatings will be required for successful construction and deployment of these reactors. In particular, heat exchanger subsystems that use molten-salt coolants will be subjected to an aggressive corrosion environment at the high operating temperatures. Heretofore, much of the materials research for heat exchanger subsystems has been focused on alloy development to achieve mechanical properties at high temperature. This project will develop and characterize prospective coatings that would be applied to nickel based super alloys to provide superior molten salt corrosion resistance and protection at temperatures greater than 900°C. The emerging Kinetic Metallization process, which can deposit coatings at low temperatures, enables the use of protective coating formulations that heretofore were not possible with electroplating or thermal spray techniques. In Phase, I coating formulations based on three different alloy systems will be investigated. Corrosion testing and mechanical testing will focus on identifying those coating formulations that offer the highest performance potential for molten salt corrosion protection at the required operating temperatures. Commercial Applications and other Benefits as described by the awardee: Nuclear power plants generate approximately 20% of U.S. electrical power without producing harmful greenhouse gases or air pollutants. Generation IV nuclear power plants using Advance Gas Cooled Reactors are proposed for generating future electrical power and hydrogen production. This project will advance the materials required to implement these reactors, by providing coating formulations and processes for protecting secondary heat exchanger components from the high-temperature corrosive action of molten salts.