<p>This study examines the hot corrosion behavior of wrought and LPBF-manufactured 18Ni300 maraging steel, which serves as containment materials in concentrated solar power (CSP) plant applications. In this article, these samples are exposed to a salt mixture of NaCl (25 wt.%) and Na₂SO₄ (75 wt.%) at an operating temperature of 750&#xa0;°C for 60&#xa0;h. The corrosion kinetics have been revealed by the weight change method, and Fe₂O₃, Fe₃O₄, NiO, CoO, MoS₂, TiO₂, Fe₂Mo₃O₈ and spinel oxides such as NiFe₂O₄ and CoFe₂O₄ are formed at the surface. The oxide layers on the wrought 18Ni300 steel are porous and prone to spallation, leading to continuous exposure of fresh surfaces to hot corrosion. In contrast, the LPBF samples, with their controlled fine-grain cellular microstructure, large grain boundary, and high dislocation densities, exhibit a more homogeneous, less porous, and intact protective oxide layer, resulting in superior corrosion resistance. Furthermore, aged samples of both wrought and LPBF maraging steel, characterized by coarse grains and low dislocation density, are more susceptible to corrosion compared to their as-received counterparts. Notably, the additively manufactured LPBF samples consistently exhibit lower corrosion rates and therefore higher corrosion resistance than the wrought samples from the outset of exposure, attributable to their hierarchical microstructure and high dislocation density.</p>