Effect of Si content on the oxidation behavior of CoCrWSi coatings at 900 °C

In this study, CoCrWSi coatings with different Si contents were prepared via high-velocity oxygen fuel spraying, and the effect of Si content on their high-temperature oxidation resistance in air was studied at 900 & DEG;C. The microstructures and chemical compositions of oxide scales were characterized through scanning electron mi-croscopy, electron probe microanalysis, and X-ray diffraction. The results revealed that the oxidation resistance of the produced CoCrWSi coatings gradually increased with increasing Si content. Moreover, the beneficial ef-fects of Si content on the oxidation resistance were discussed in terms of Si depletion. The addition of Si pre-vented the outward diffusion of Cr atoms, and inhibited internal oxidation, while the depth of internal oxidation varied significantly with the oxidation time.