Oxidation behavior of TiB₂–SiC nanocomposite coatings deposited by magnetron sputtering

TiB₂ and TiB₂-SiC coatings were deposited by magnetron sputtering using pure TiB₂ targets and TiB₂-20 mol. % SiC composite targets, and their high-temperature oxidation behavior in air was investigated. The addition of SiC transformed the TiB₂ coating from a columnar microstructure to a densely nanocrystalline structure. After air annealing at 500 °C, a small amount of B₂O₃ oxide scales began to form on the surface of T20S. As the annealing temperature increased, the T0S coating developed loose B₂O₃ and TiO₂ oxide layers and was completely oxidized at 1000 °C. In contrast, the dense B₂O₃ and amorphous borosilicate passivation layer in the T20S coating inhibited oxygen diffusion, delaying complete oxidation until annealing at 1100 °C.