Heterogeneous 3D Morphological Evolution of Ni Microparticles in Molten Salts: Visualized by Operando Synchrotron X-ray Nano-tomography

Ni-based superalloys are promising materials for high-temperature molten salt (MS) energy generation and storage. Studying morphological chemical evolution of pure Ni in MS provides fundamental knowledge technologies corrosion mitigation. Here, real-time 3D changes microparticles KCl-MgCl2 were studied by operando synchrotron X-ray nano-tomography at 700°C. Rapid particle agglomeration occurred, without significant reactions, such as oxide or chloride formation. The growth evolved differently from classical coarsening sintering behaviors occurred nonuniformly, with other regions showing slight dissolution Ni. nanoparticles found to be dispersed many areas the samples, either microparticle radiation-induced nanoparticle formation mechanisms. This study discusses important factors, i.e., thermal gradient, amounts metals, radiation effect, that influence MS, critical understanding material–MS interactions well practical applications.