中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 25 No. 1 January 2015 |
(College of Materials Science and Engineering, Heilongjiang University of Science and Technology,
Harbin 150022, China)
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