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The effects of Si incorporation on the electrochemical and nanomechanical properties of DLC thin films

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Papakonstantinou, P, Zhao, JF, Lemoine, P, McAdams, ET and McLaughlin, JAD (2002) The effects of Si incorporation on the electrochemical and nanomechanical properties of DLC thin films. DIAMOND AND RELATED MATERIALS, 11 (3-6, Sp. Iss. SI). pp. 1074-1080. [Journal article]

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DOI: S0925-9635(01)00656-2

Abstract

Silicon-doped diamond-like carbon (DLC) films with a Si content of up to 20.2 at.% were grown on Al2O3-TiC substrate by plasma-enhanced chemical vapour deposition. The influence of Si addition on the bonding structure, nanomechanical and corrosion behaviour of the DLC films was investigated by Raman and X-ray photoelectron (XPS) spectroscopy,nano-indentation, potentiodynamic and electrochemical impedance spectroscopy (EIS). Silicon addition promoted the formation of sp(3) bonding and reduced the hardness. The deterioration of the nanomechanical properties is related to the increased hydrogen contentin the films, leading to the formation of a polymeric sp(3) CHn structure. The high hydrogen concentration in the Si-containing DLC samples was established by the increased Raman background slope. The EIS were analysed within the context of an equivalent circuit, whichincorporated two time constants representing the DLC coating and the solution/Al2O3-TiC interface, Introduction of Si in the DLC led to significant improvements in the corrosion resistance of DLC, as revealed by increase in the charge transfer resistance and reduction in the anodic current of the polarisation curves. Films with a thickness of 20 nm remained intact after the polarisation scan when the Si concentration was increased above 11.8 at.%. The improvements in corrosion resistance are related to the formation of a passivationlayer, which fills the pores present in the films. (C) 2002 Elsevier Science B.V. All rights reserved.

Item Type:Journal article
Keywords:electrochemical impedance; pinholes; Raman spectroscopy; hardness; corrosion; Si-doped diamond-like carbon (DLC)
Faculties and Schools:Faculty of Computing & Engineering
Faculty of Computing & Engineering > School of Engineering
Research Institutes and Groups:Engineering Research Institute
Engineering Research Institute > Nanotechnology & Integrated BioEngineering Centre (NIBEC)
ID Code:302
Deposited By:Mrs Ann Blair
Deposited On:14 Sep 2009 10:59
Last Modified:24 Feb 2014 10:05

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