On the early stage isothermal oxidation of APS CoNiCrAlY coatings

G. Di Girolamo, M. Alfano, L. Pagnotta, A. Taurino, J. Zekonyte, R. J. K. Wood

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The aim of this study is to analyze the evolution of microstructural and room temperature mechanical properties of air plasma sprayed (APS) CoNiCrAlY coatings before and after early stage high-temperature oxidation. To this purpose, selected samples were isothermally heat treated at 1110 °C for different durations. Phase analysis and oxide scale characterization were performed using x-ray diffraction. Morphological and microstructural features of as-sprayed and oxidized CoNiCrAlY coatings were analyzed by scanning electron microscopy and energy dispersive x-ray spectroscopy. After heat treatment, a duplex oxide scale, composed of an inner α-Al2O3 layer and an outer spinel-type oxide layer, was observed on coating top-surface. The nanoindentation technique was employed to study the evolution of the mechanical properties. An increase in Young’s modulus and hardness with increasing the aging time was observed, this effect was mainly addressed to the partial densification of coating microstructure.
    Original languageEnglish
    Pages (from-to)1989-1997
    JournalJournal of Materials Engineering and Performance
    Volume21
    Issue number9
    Early online date10 Jan 2012
    DOIs
    Publication statusPublished - Sep 2012

    Keywords

    • coatings
    • heat resistant metals
    • thermal spray

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