Evaluation of the Compatibility of Aluminide Coatings in High-Temperature Sodium for Fast Reactor Application

Nickel and iron aluminide coatings were identified as possible candidates for hardfacing materials in Sodium Fast Reactors. Both coatings were developed on two steel grades of interest for the next French Sodium Fast Reactor prototype, 316L(N) and T91. Pack cementation and slurry were employed as aluminization processes. The compatibility of all coatings with purified Na was evaluated at 550 °C for exposure times up to 4250 h. All coatings evidenced high chemical stability in Na even though Na penetration and slow coating dissolution could be evidenced. The penetration depth of Na was observed to depend on the coating nature induced by the deposition process.