A comparative study of reactive direct current magnetron sputtered CrAlN and CrN coatings

Barshilia, Harish C and Selvakumar, N and Deepthi, B and Rajam, KS (2006) A comparative study of reactive direct current magnetron sputtered CrAlN and CrN coatings. Surface and Coatings Technology, 201 (6). pp. 2193-2201. ISSN 0257-8972

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    Abstract

    Approximately 1.5 x3BC;m thick CrN and CrAlN coatings were deposited on silicon and mild steel substrates by reactive direct current (DC)13; magnetron sputtering. The structural and mechanical properties of the coatings were characterized using X-ray diffraction (XRD) and13; nanoindentation techniques, respectively. The bonding structure of the coatings was characterized by X-ray photoelectron spectroscopy (XPS).13; The surface morphology of the coatings was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The XRD13; data showed that the CrN and CrAlN coatings exhibited B1 NaCl structure. Nanoindentation measurements showed that as-deposited CrN and13; CrAlN coatings exhibited a hardness of 18 and 33 GPa, respectively. Results of the surface analysis of the as-deposited coatings using SEM and13; AFM showed a more compact and dense microstructure for CrAlN coatings. The thermal stability of the coatings was studied by heating the13; coatings in air from 400 to 900 xB0;C. The structural changes as a result of heating were studied using micro-Raman spectroscopy. The Raman data13; revealed that CrN coatings got oxidized at 600 xB0;C, whereas in the case of CrAlN coatings, no detectable oxides were formed even at 800 xB0;C. After13; annealing up to 700 xB0;C, the CrN coatings displayed a hardness of only about 7.5 GPa as compared to CrAlN coatings, which exhibited hardness as13; high as 22.5 GPa. The potentiodynamic polarization measurements in 3.5% NaCl solution indicated that the CrAlN coatings exhibited superior13; corrosion resistance as compared to CrN coatings.13;

    Item Type: Journal Article
    Additional Information: Copyright for this article belongs to Elsevier Publishers
    Uncontrolled Keywords: CrN and CrAlN coatings;Magnetron sputtering;Structure and mechanical properties;Thermal stability;Surface roughness; Corrosion resistance
    Subjects: CHEMISTRY AND MATERIALS > Composite Materials
    Division/Department: Surface Engineering Division, Surface Engineering Division, Surface Engineering Division, Surface Engineering Division
    Depositing User: Mrs Manoranjitha M D
    Date Deposited: 31 Jan 2007
    Last Modified: 07 May 2012 10:59
    URI: http://nal-ir.nal.res.in/id/eprint/3982

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