Feasibility Study on Aluminum Under Laser Ablation for Corrosion Resistance in Molten Salt

Molten salt is a prevalent medium in nuclear technology, especially in both reactors and waste separation (pyroprocessing) routines. Thus, the application dealing with the molten salt requires compatible materials that can withstand its aggressive environment. Research studies have shown that the purity of the molten salt environment can influence corrosion rates. Fission products, moisture, and oxide corrosion contents all distribute into the salt’s impurity and how it reacts within the system. The naturally occurring corrosion creates some protection via incomplete passivation layers; however, these same impurities start instability in the film through localized attacks. Laser ablation treatments in other research fields have proven useful in the improvement of corrosion resistance in various materials. Yet, this approach has not been tested in molten salt towards nuclear engineering applications. Thus, this becomes a motivation for our study to determine the feasibility of using the laser ablation technique on aluminum samples, creating an oxide layer and testing them in a eutectic LiCl-KCl salt at 773 K simulating a pyroprocessing environment. Over the course of the corrosion test, data sets were collected to allow electrochemical analysis – 24 hour rounds of open circuit voltage, electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV). Detailed results will be presented and discussed.