Study of Oxidation and Hot Corrosion of Nb-Si Composites at ۹۰۰°C

Nb-Si composites, due to their low density (۶.۶-۷.۲ g/cm³) and high melting point (۱۷۵۰°C), hold significant importance for structural and high-temperature applications. Considering that Nb-Si composites often operate at elevated temperatures in contact with combustion gases or other oxidizing environments, understanding their oxidation and high-temperature corrosion behavior at ۹۰۰°C is crucial. The kinetic curves obtained for oxidation and hot corrosion of this alloy exhibit a parabolic stage followed by a linear stage. During the initial oxidation stage (۱ to ۵۰ hours), a thin, continuous protective layer forms on the alloy surface. Compared to oxidation in static air, the linear stage during hot corrosion appears much earlier, and catastrophic breakdown of the oxide layer occurs after ۲۰ to ۱۰۰ hours of exposure. This demonstrates that molten salts (NaCl and Na۲SO۴) can significantly accelerate the oxidation process of the alloy.

کلیدواژه ها:

Oxidation ، Hot Corrosion ، Nb-Si Alloys