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Cyclic oxidation characteristics of HVOF thermal-sprayed NiCoCrAlY and CoNiCrAlY coatings at 1000 °C

Feizabadi, A ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jallcom.2018.02.282
  3. Publisher: Elsevier Ltd , 2018
  4. Abstract:
  5. Thermal-sprayed MCrAlY coatings have become widespread in various industries such as power plants, aeronautics, and oil and gas firms. High-temperature oxidation behavior of these coatings is therefore of significance. Spraying of two prevalent MCrAlY powders (NiCoCrAlY and CoNiCrAlY) on Hastelloy substrate by high velocity oxygen and fuel method and exposing them to 1000 °C air for resolving of their cyclic oxidation behavior are presented in this paper. The coatings were characterized by x-ray diffraction, scanning electron microscopy and energy-dispersive x-ray spectroscopy. The obtained oxidation kinetic indicated that at 1000 °C, the thermally sprayed NiCoCrAlY coating has greater resistance to oxidation than CoNiCrAlY. While oxidation rate of the former follows a parabolic rate equation with specific rate of 5.1 × 10−3 (μm)2 h−1 at 1000 °C, the oxidation rate for the latter has a specific rate of 12.1 × 10−3 (μm)2 h−1. © 2018 Elsevier B.V
  6. Keywords:
  7. Cyclic oxidation ; High velocity oxygen and fuel ; Air ; Chromium alloys ; Coatings ; Cobalt alloys ; Energy dispersive spectroscopy ; Gas plants ; HVOF thermal spraying ; Oxidation ; Scanning electron microscopy ; Sprayed coatings ; Thermooxidation ; X ray diffraction ; X ray spectroscopy ; Cyclic oxidation behavior ; Energy dispersive X ray spectroscopy ; High temperature oxidation behavior ; High velocity ; MCrAlY coatings ; NiCoCrAlY coatings ; Thermally grown oxide ; Aluminum alloys
  8. Source: Journal of Alloys and Compounds ; Volume 746 , 25 May , 2018 , Pages 509-519 ; 09258388 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0925838818307771