Multi-scale Structured Composite Coatings by Plasma Transferred Arc for Nuclear applications

In nuclear plants, the replacement of Stellite cobalt-base alloy has been implemented in US since the 70’s as the activation of cobalt forms a radioisotope that has a half-life of 5.27 years and contaminates cooling circuits. Iron and nickel-based alloys have been proposed as Co-free candidate materials. However, the development of the next generation of nuclear plants with more stringent operational conditions raises new investigations for hardfacing materials. These investigations can take advantage of the recent progress in multi-scale structured composite coatings.

This work deals with cobalt-free nickel-base alloy deposited by plasma transferred arc on stainless steel substrates with the addition of micrometric and sub-micrometric ceramic powder. The composite coatings are intended to be used in Generation-IV sodium-cooled fast reactor. The effect of the addition of ceramic particles in metallic matrix is investigated by the examination of the microstructure of coatings, and micro hardness and sliding wear tests.