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CrN/NbN coatings deposited by HIPIMS : A preliminary study of erosion-corrosion performance

Purandare, Yashodhan and Ehiasarian, A.P. and Stack, Margaret and Hovsepian, P. (2010) CrN/NbN coatings deposited by HIPIMS : A preliminary study of erosion-corrosion performance. Surface and Coatings Technology, 204 (8). pp. 1158-1162. ISSN 0257-8972

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    Abstract

    Nanoscale CrN/NbN multilayer PVD coatings have exhibited resistance to erosion-corrosion. However, growth defects (under dense structures and droplets) in the coating produced by some deposition technologies reduce the ability to offer combined erosion-corrosion resistance. In this work a novel High Power Impulse Magnetron Sputtering (HIPIMS) technique has been utilised to pretreat substrates and deposit dense nanoscale CrN/NbN PVD coatings (HIPIMS-HIPIMS technique). This new technique, rich with metal ion plasma, deposits very dense structures and offers virtually defect free coatings (free of droplets as observed in cathodic arc technique and under-dense structures observed in standard dc sputtering). Plasma diagnostic studies revealed a high metal ion-to-gas ion ratio (Cr:Ar) of 3:1 for HIPIMS pretreatment conditions with the detection of 14% Cr**2+ and 1% Cr**3+ and J..S of 155 mAcm**-2. For deposition conditions the metal ion-to-gas ratio was approximately 1:4 which is significantly higher compared to DC at 1:30. Characterisation results revealed a high adhesion of L..C 80 N, high hardness of 34 GPa and Young's modulus of 381 GPa. Low friction coefficient (0.46) and dry sliding wear coefficient, K..C (1.22 X 10**-15 M**3 nM**-1) were recorded. The effect of deposition technique (droplet defect and intergranular void free coatings) on erosion-corrosion resistance of CrN/NbN coatings has been evaluated by subjecting the coatings to a slurry impingement (Na..2 CO..3 + NaHCO..3 buffer solution with Al..2 O..3 particles of size 500-700 µm) at 90° impact angle with a velocity of 4 ms**-1. Experiments have been carried out at -1000 mV, +300 mV and +700 mV representing 3 different corrosion conditions.

    Item type: Article
    ID code: 13650
    Notes: Impact Factor: 1.793, Half-Life: 5.7
    Keywords: erosion-corrosion, erosion, corrosion, HIPIMS, surface coatings, mechanical engineering, Mechanical engineering and machinery, Mining engineering. Metallurgy, Mechanical Engineering, Mechanics of Materials, Surfaces, Coatings and Films
    Subjects: Technology > Mechanical engineering and machinery
    Technology > Mining engineering. Metallurgy
    Department: Faculty of Engineering > Mechanical and Aerospace Engineering
    Related URLs:
    Depositing user: Ms Katrina May
    Date Deposited: 02 Dec 2009 14:52
    Last modified: 12 Jun 2014 10:56
    URI: http://strathprints.strath.ac.uk/id/eprint/13650

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