Browsing by Author "Roest, R"

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    Adhesion of sol-gel derived hydroxyapatite nanocoatings on anodised pure titanium and titanium (Ti6Al4V) alloy substrates
    (Elsevier, 2011-02-25) Roest, R; Latella, BA; Heness, G; Ben-Nissan, B
    The mechanical properties and adhesion behaviour of sol–gel derived hydroxyapatite (HA) nanocoatings on commercially pure (cp) titanium (Ti) and Ti6Al4V alloy have been determined and related to anodising treatment. The surface roughness, wetting and coating characteristics were examined using profilometry, contact angle, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Nano-indentation was used to determine the Young's modulus and hardness of the coatings, while microtensile tests were used to introduce controlled strains in the coatings through the cp Ti and TiAl6V4 alloy substrates, from which the strength, fracture toughness and adhesion behaviour could be ascertained based on multiple cracking and delamination events. The toughness of the HA coatings is found to be slightly lower to that of equivalent bulk pure HA ceramics. The substrate and the anodized layer thickness have the most influence on the interfacial adhesion of HA, with nanocoatings on Ti6Al4V exhibiting superior interfacial bonding in comparison to cp Ti. © 2011, Elsevier Ltd.
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    An investigation of sol gel coated zirconia thin films on anodised titanium substrate by secondary ion mass spectrometry and scanning electron microscopy
    (Institute of Materials Engineering Australasia, 2007-12-12) Roest, R; Atanacio, AJ; Latella, BA; Wuhrer, R; Ben-Nissan, B
    Zirconia sol-gel-derived ceramic coatings have a variety of uses, due to their ease of production and ability to coat complex shapes. The sol-gel's nanocrystalline grain structure results in improved mechanical properties of the zirconia coating, which further aids their use in a variety of applications from thermal barrier coating to improved tribological properties on titanium substrates. Stabilised zirconia thin films were spin coated on anodised titanium substrates. The titanium was anodised in a dilute H3PO 4ZH2SO4 solution before spin coating with the zirconia sol gel. These films were then studied using secondary ion mass spectrometry (SIMS), to depth profile the elemental species through to the titanium substrate. In conjunction, scanning electron microscopy (SEM) and X-ray microanalysis were used to examine the craters formed by SIMS to gain an understanding of the diffusion gradient existing with the anodised titanium substrate and zirconia thin film. © 2007 Institute of Materials Engineering Australasia.