Abstract
NiCoCrAlY(SiB) coatings were deposited on the nickel base superalloys DZ125 and DSM11 by arc ion plating (AIP). The corrosion behavior of the bare alloys and the protective coatings in molten 75 wt.% Na 2SO 4+25 wt.% K 2SO 4 at 900 °C in air was tested for 90 h. The results indicated that DZ125 superalloy suffered catastrophic corrosion after 5 h exposure and a thick porous oxide scale (500–600 μm) interspersed with Ni 3S 2 and alloy particles formed on the alloy. For the Cr-rich DSM11 alloy, a mild corrosion attack happened, but severe internal Al-rich oxidation occurred inside the alloy. With NiCoCrAlY and NiCoCrAlYSiB coatings, the hot corrosion resistance of the systems was improved due to the formation of an α-Al 2O 3 scale. The hot corrosion resistance of the coatings with additions of Si and B can be improved by promoting the growth of a dense and continuous α-Al 2O 3 layer in the initial stage and improving the adherence of the oxide scale to the coating in the subsequent hot corrosion process. The hot corrosion degradation mechanism of the NiCoCrAlYSiB coatings and the influence of the substrate materials on the behavior of the whole system were also investigated.
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.
