Oxidation of Al2O3-dispersion chromizing coating by pack-cementation at 800 ℃
(College of Materials Science and Engineering, Heilongjiang Institute of Science and Technology,Harbin 150027, China)
Abstract: Preparation and oxidation of an Al2O3-dispersed chromizing coating were investigated by chromizing an as- electrodeposited Ni-Al2O3 nanocomposite film using a conventional pack-cementation method at a greatly decreased temperature (800 ℃). For comparison, chromizing was also performed with the same condition on an as-deposited Ni film without Al2O3 nanoparticles. Oxidation at 900 ℃ indicates that, compared with the Al2O3-free chromizing coating, the Al2O3-dispersed chromizing coating exhibits a increased oxidation resistance, due to the formation of purer and denser chromia scale. The effect of Al2O3 on the coating formation and the coating oxidation behavior was discussed in details.
Key words: electrodeposition; composite coating; oxidation; reactive element effect