Size effects on high temperature oxidation of MCrAlY coatings processed via APS and HVOF depositions
نویسندگان
چکیده
The paper demonstrates how defects inherited from the deposition processes can severely impair lifetime of MCrAlY coatings in service. oxidation behavior two NiCoCrAlY was investigated at 1150 °C up to 500 h. had same nominal composition but were processed by different projection techniques: air plasma spray (APS) and high velocity oxy fuel (HVOF). Freestanding coating specimens extracted coated system thinned down thicknesses ranging 520 15 μm order investigate size effects inherent response. rate APS found be insensitive specimen thickness, while that HVOF increased with due greater intersplat oxidation. thinner than 60 experienced intrinsic chemical failure (InCF) Al consumption form Al2O3 scale. In comparison, a thickness 367 subject InCF after 250–350 h This first stage resulted formation Cr2O3 layer Al2O3/metal interface once activity low enough thermodynamically allow form. addition, thick developed mechanically induced (MICF) resulting (Ni,Co)(Cr,Al)2O4 spinels on top scale within oxide intrusions. occurrence MICF associated concomitant intrusive spallation external
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ژورنال
عنوان ژورنال: Surface & Coatings Technology
سال: 2022
ISSN: ['1879-3347', '0257-8972']
DOI: https://doi.org/10.1016/j.surfcoat.2022.128483