Abstract
High temperature oxidation behavior of protective oxide scales can be improved by surface doping with reactive elements such as cerium. In this investigation, an intermediate Ni-CeO2 layer was electrodeposited on the surface of Rene 80 nickel-based superalloy before pack cementation aluminizing treatment. Electrodeposition of the Ni-CeO2 layer was carried out using direct current and Watts nickel electroplating bath containing 30g/lit nano ceria particles. Electrodeposited specimens were aluminized in a powder mixture of aluminum, ammonium chloride, and alumina by a two-step treatment at 760 and 1040°C to form an inward growth-type coating. Cross-sections of the coated specimens were studied by means of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry. The results showed that after aluminizing the composite intermediate layer converts to an Al-rich NiAl layer with a porous and CeO2-free surface zone below which a CeO2-containing layer exists. Three-zone microstructure of two-step aluminide coatings on nickel-based superalloys was observed below the CeO2-containing layer. The mechanism of coating formation was discussed. The oxidation resistance of the CeO2 modified coating in 10 five-hour cycles at 1050°C was considerably better than the unmodified coating.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
