The effect of Nb and Si on the hot corrosion behaviors of TiAl coatings on a Ti-6Al-4V alloy

摘要

Hot corrosion behaviors of TiAl coatings with different Nb and Si additions in a Na2SO4 + NaCl salt mixture at 800 degrees C were investigated. Corrosion kinetics was evaluated based on mass change measurements. The corrosion products and morphologies of the corrosion scales were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adhesion strength of the corrosion scales was evaluated by acoustic emission (AE). High Si addition on its own and a co-addition of a high content of Si and an appropriate content of Nb improved the hot corrosion resistance of the coatings.