Raman spectroscopy studies on the thermal stability of TiN, CrN, TiAlN coatings and nanolayered TiN/CrN, TiAlN/CrN multilayer coatings

Barshilia, Harish C and Rajam, KS (2004) Raman spectroscopy studies on the thermal stability of TiN, CrN, TiAlN coatings and nanolayered TiN/CrN, TiAlN/CrN multilayer coatings. Journal of Materials Research, 19 (11). pp. 3196-3205.

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    Abstract

    About 1.5-um-thick single-layer TiN, CrN, TiAlN coatings and nanolayered TiN/CrN, TiAlN/CrN multilayer coatings were deposited on silicon (111) substrates using a13; reactive direct current magnetron sputtering process. Structural characterization of the coatings was done using x-ray diffraction (XRD) and micro-Raman spectroscopy. All13; the coatings exhibited NaCl B1 structure in the XRD data. Raman spectroscopy data of as-deposited coatings exhibited two broad bands centered at 230x2013;250 and 540x2013;630 cmx2212;1.13; These bands have been assigned to acoustical and optical phonon modes, respectively. Thermal stability of the coatings was studied by heating the coatings in air in a13; resistive furnace for 30 min in the temperature range 400x2013;900 xB0;C. Structural changes as a result of heating were characterized using Raman spectroscopy and XRD. Raman13; data showed that TiN, CrN, TiN/CrN, TiAlN, and TiAlN/CrN coatings started to oxidize at 500, 600, 750, 800, and 900 xB0;C, respectively. To isolate the oxidation-induced spectral changes as a result of heating of the coatings in air, samples were also annealed in vacuum at 800 xB0;C under similar conditions. The Raman data of vacuum-annealed coatings showed no phase transformation, and intensity of the optical phonon mode increased and shifted to lower frequencies. The origin of these spectral changes is discussed in terms of defect structure of the coatings. Our results indicate that the thermal stability of nanolayered multilayer coatings is superior to the13; single-layer coatings.

    Item Type: Journal Article
    Uncontrolled Keywords: TiAlN/CrN coatings;TiAlN and nanolayered TiN/CrN;CrN;Raman spectroscopy studies on the thermal stability of TiN
    Subjects: PHYSICS > Solid-State Physics
    AERONAUTICS > Aerodynamics
    Division/Department: Surface Engineering Division, Surface Engineering Division
    Depositing User: Mrs Neetu Chandra
    Date Deposited: 19 May 2006
    Last Modified: 22 Aug 2011 10:16
    URI: http://nal-ir.nal.res.in/id/eprint/1476

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