Development of coatings for fusion power applications

Coatings have been proposed as the solution to critical materials constraints for most of the blanket concepts under development for fusion power applications. However, the international programs on coating development are focused primarily on electrically insulating coatings to mitigate the magneto-hydrodynamic pressure drop in self-cooled lithium/vanadium blanket concepts, and on tritium permeation barriers to reduce tritium permeation from Pb–Li into the water coolant in water-cooled Pb–Li concepts. Emphasis of the insulator coating development is on CaO and AlN coatings formed on vanadium alloys either in situ in lithium or by vapor deposition processes. The tritium barrier coating development is focused on Al2O3 formed on aluminized martensitic steels by several processes. This paper presents an overview of the fundamental materials issues associated with the various coatings and the status of coating development for the various applications.