Compositionally graded thermal barrier coating by hybrid thermal spraying route and its non-isothermal oxidation behavior

Subhasisa Nath, Indranil Manna, Jyotsna Dutta Majumdar

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    9 Citations (Scopus)

    Abstract

    The present study concerns a detailed investigation of the characteristics and oxidation resistance property of a duplex and compositionally graded thermal barrier coating on Inconel 718. The duplex coating consists of a CoNiCrAlY bond coat layer sprayed on to sand-blasted Inconel 718 substrate (by high velocity oxy-fuel spraying) followed by deposition of a yttria-stabilized zirconia (YSZ) top coat by plasma spraying. The compositionally graded coating consists of several layers deposited by plasma spraying of pre-mixed CoNiCrAlY and YSZ powders in the weight ratios of 70:30, 50:50, 30:70, and 0:100 varying from the bond coat to the top surface, respectively. A detailed investigation of the microstructure, composition, and phases in the coating and its non-isothermal oxidation behavior from room temperature to 1250°C was performed. Oxidation proceeds by three stages in the as-received Inconel 718 and the compositionally graded coating, but by two stages in the duplex coating with a maximum activation energy for oxidation in the compositionally graded coating at high temperature (stage III). The kinetics and mechanism of oxidation were established.
    Original languageEnglish
    Pages (from-to)901-917
    Number of pages17
    JournalJournal of Thermal Spray Technology
    Volume22
    Issue number6
    DOIs
    Publication statusPublished - 2013

    Keywords

    • Functionally graded coating
    • HVOF spraying
    • Microstructure
    • Oxidation
    • Phase analysis
    • Plasma spraying
    • Thermal barrier coating

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