Preparation of High-Entropy Silicide Coating on Tantalum Substrate by Silicon Infiltration Method and Its Antioxidant Performance

High-entropy silicide (MeSi2) coating was prepared by the slurry method and silicon infiltration method using Mo, Cr, Ta, Nb, W, and Si elemental powders as raw materials. The coating consisted of four layers, including a porous MeSi2 layer, a (CrTa)Si layer, a TaSi2 layer, and a Ta5Si3 layer from outside to inside. At 600 °C, Si was preferentially oxidized to form SiO2 oxide film. The mass gain rate of the coating was 0.2 mg/cm2 over a period of 100 h oxidation, eliminating the phenomenon of low-temperature pulverization. At 1200 °C, MeSi2 coating had a protection time of 20 h. During the oxidation process, the coating generated metal oxides, forming a thin SiO2 oxide film. TaSi2 and Ta5Si3 gradually transformed into Ta2O5, and the coating eventually failed.