Abstract:A Ni-7Cr-4Al (mass fraction, %) nanocomposite was fabricated by co-electrodeposition of Ni with Cr (40 nm) and Al (100 nm) nanoparticles from a nickel sulfate bath, and its oxidation at 800 °C in air and hot corrosion under molten 75% Na₂SO₄ + 25% NaCl salts (mass fraction) at 750 °C were investigated. For comparison, Ni-11Cr nanocomposite and Ni-film were also investigated in order to elucidate the effect of Cr nanoparticles. The results indicate that Cr and Al nanoparticles are dispersed in the electrodeposited nanocrystalline Ni grains (in size range of 20-60 nm). Ni-7Cr-4Al nanocomposite exhibits a dramatically increased oxidation resistance compared with Ni-11Cr nanocomposite and Ni-film due to the fast formation of alumina scale, which also improves its hot corrosion resistance under molten 75% Na₂SO₄ + 25% NaCl salts.

Key words: Ni-Cr-Al coating; nanocomposite; co-electrodeposition; oxidation; hot corrosion