Deposition and characterization of TiAlN/Si3N4 superhard nanocomposite coatings prepared by reactive direct current unbalanced magnetron sputtering

Barshilia, Harish C and Deepthi, B and Rajam, KS (2006) Deposition and characterization of TiAlN/Si3N4 superhard nanocomposite coatings prepared by reactive direct current unbalanced magnetron sputtering. Vaccum, 81 (4). pp. 479-488.

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    Abstract

    Superhard nanocomposite coatings of TiAlN/Si3N4 with varying silicon contents were synthesized using reactive direct current (DC)13; unbalanced magnetron sputtering. The Si and TiAl targets were sputtered using an asymmetric bipolar-pulsed DC power supply and a13; DC power supply, respectively, in Ar+N2 plasma. The structural and mechanical properties of the coatings were characterized using13; X-ray diffraction (XRD) and nanoindentation techniques, respectively. The elemental composition of the TiAlN/Si3N4 nanocomposite13; coatings was determined using energy-dispersive X-ray analysis and the bonding structure was characterized by X-ray photoelectron13; spectroscopy. The surface morphology of the coatings was studied using atomic force microscopy. The XRD data showed that the13; nanocomposite coatings exhibited (1 1 1) and (2 0 0) rexFB02;ections of cubic TiAlN phase. The broadening of the diffraction peaks with an13; increase in the silicon content in the nanocomposite coatings, suggested a decrease in the average crystallite size. The TiAlN/Si3N413; nanocomposite coatings exhibited a maximum hardness of 43 GPa and an elastic modulus of 350 GPa at a silicon concentration of13; approximately 11 at%. The hardness and the elastic modulus of the nanocomposite coatings decreased signixFB01;cantly at higher silicon13; contents. Micro-Raman spectroscopy was used to characterize the structural changes as a result of heating of the nanocomposite13; coatings in air (400x2013;850 1C) and in vacuum (900 1C). The Raman data of the nanocomposite coatings annealed in air and vacuum showed13; better thermal stability as compared to that of the TiAlN coatings. Similarly, the nanocomposite coatings deposited on mild steel substrates exhibited improved corrosion resistance.13;

    Item Type: Journal Article
    Uncontrolled Keywords: TiAlN/Si3N4 superhard nanocomposite coatings;Unbalanced magnetron sputtering;Structural and mechanical properties; Thermal stability;Corrosion behavior
    Subjects: CHEMISTRY AND MATERIALS > Composite Materials
    Division/Department: Surface Engineering Division, Surface Engineering Division, Surface Engineering Division
    Depositing User: Mrs Manoranjitha M D
    Date Deposited: 15 Mar 2007
    Last Modified: 07 May 2012 10:59
    URI: http://nal-ir.nal.res.in/id/eprint/3981

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