Effect of nanocrystallization on hot corrosion resistance of Ti-48Al-8Cr-2Ag alloy in molten salts

摘要

Magnetron-sputter deposition was used to produce Ti-48Al-8Cr-2Ag coating on a cast alloy substrate with the same composition. Hot corrosion was carried out in molten (Na,K)_2SO_4 and Na_2SO_4+NaCl at 900 deg C. The sputtered nanocrystalline coating shows much better hot-corrosion resistance in molten (Na,K)_2SO_4 as a result of the formation of a continuous and compact Al_2O_3 scale. The nanocrystallization of TiAlCrAg alloy prolongs the incubation of breakaway corrosion and improves the hot-corrosion resistance of TiAlCrAg alloy in molten Na_2SO_4 + NaCl. The relevant corrosion mechanism was discussed.