Browsing by Author "Ben-Nissan, B"

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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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    Design of H-knee: a modular ceramic total knee replacement prosthesis
    (Australasian Ceramic Society, 1988-09) Payten, WM; Ben-Nissan, B
    Degenerative joint disease, recognized as an increasing problem for society, is a direct result of an aging population. When patients present with joint pain, their primary concern is the relief of pain and return to a mobile life style. This often requires replacement of skeletal parts, such as hips, knees, elbows, finger joints, shoulder, and teeth, or fusion of vertebrae, and repair or augmentation of the jaw and bones of the skull. The result is a current worldwide orthopedic market valued at over $5 billion; joint replacement represents 68% of this market. The demand for knee replacements is increasing at approximately 17%/ p.a., with some 300,000 knee joints replaced each year in the United States alone. This increase results in part from increased confidence in using such prostheses. Unfortunately, results do not reinforce this confidence: Long-term clinical results are scattered, and, although the overall rate of failure is reasonably low, it remains unacceptable. A further complication arises because the increase in younger patients undergoing total knee arthroplasty (TKA) may well lead to a higher incidence of eventual failure.
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    Development of a modular ceramic knee prosthesis
    (Humana Press, 2000) Payten, WM; Ben-Nissan, B
    Degenerative joint disease, recognized as an increasing problem for society, is a direct result of an aging population (1). When patients present with joint pain, their primary concern is the relief of pain and return to a mobile life style. This often requires replacement of skeletal parts, such as hips, knees, elbows, finger joints, shoulder, and teeth, or fusion of vertebrae, and repair or augmentation of the jaw and bones of the skull. The result is a current worldwide orthopedic market valued at over $5 billion; joint replacement represents 68% of this market. The demand for knee replacements is increasing at approx 17%/yr, with some 300,000 knee joints replaced each year in the United States alone (2). This increase results in part from increased confidence in using such prostheses. Unfortunately, results do not reinforce this confidence: Long-term clinical results are scattered (3), and, although the overall rate of failure is reasonably low, it remains unacceptable. A further complication arises because the increase in younger patients undergoing total knee arthroplasty (TKA) may well lead to a higher incidence of eventual failure. © Springer Science+Business Media New York 2000
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    Development of carbon nanotube reinforced hydroxyapatite bioceramics
    (Elsevier B. V., 2005-11-27) Kealley, CS; Elcombe, MM; Ben-Nissan, B; van Riessen, A
    This paper reports development of a production method to create a composite material that is biocompatible, which will have high mechanical strength and resilience, and be able to withstand exposure to the physiological environment. The chemical precipitation conditions necessary for the production of single phase synthetic hydroxyapatite (HAp) have been determined. Neutron and X-Ray diffraction have been used extensively to follow the effects of drying and heat treatments on the process and to confirm that the final material is single phase. The neutron diffraction data has enabled the positions of the hydroxide bonds to be determined. Subsequent development of a technique to produce a HAp + carbon nanotube composite material is also reported. A method has been determined to remove the soot impurity from the nanotubes with minimal degradation of the nanotube. Neutron diffraction patterns collected before and after sintering show that the nanotubes have remained in the structure while most of the remaining soot has burnt off. Small angle neutron scattering, in conjunction with transmission electron microscopy, also shows preservation of the carbon nanotubes. Mechanical property testing is in progress and results will be reported. © The Authors
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    Development of carbon nanotube-reinforced hydroxyapatite bioceramics
    (Elsevier B. V., 2006-11-15) Kealley, CS; Elcombe, MM; van Riessen, A; Ben-Nissan, B
    This paper reports development of a production method to create a composite material that is biocompatible, which will have high mechanical strength and resilience, and be able to withstand exposure to the physiological environment. The chemical precipitation conditions necessary for the production of single-phase synthetic hydroxyapatite (HAp) and a HAp and carbon nanotube (CNT) composite material have been optimised. Neutron diffraction patterns collected before and after sintering show that the nanotubes have remained intact within the structure, while most of the remaining soot has burnt off. Small-angle neutron scattering, in conjunction with scanning electron microscopy (SEM), also shows preservation of the CNTs. Hot isostatically pressed samples showed excellent densification. Neutron diffraction data has enabled the positions of the hydroxide bonds to be determined, and shown that the addition of the CNTs has had no effect on the structural parameters of the HAp phase, with the exception of a slight reduction in the unit cell parameter α . © 2006 Elsevier B.V.
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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.
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    Micro- and nano-indentation of a hydroxyapatite-carbon nanotube composite
    (American Scientific Publishers, 2008-08) Kealley, CS; Latella, BA; van Riessen, A; Elcombe, MM; Ben-Nissan, B
    The mechanical properties of pure synthetic hydroxyapatite and hydroxyapatite-carbon nanotube composites were examined. Vickers microhardness and nanoindentation using a Berkovich tipped indenter were used to determine the hardness, fracture toughness and Young's modulus of the pure hydroxyapatite matrix and the composite materials. Microscopy showed that for the composites produced the carbon nanotubes were present as discrete clumps. These clumps induced a detrimental effect on the hardness of the materials, while the fracture toughness values were not affected. This would be undesirable in terms of using the material for biomedical implant applications. It should be noted that the carbon nanotubes used contained free graphite. As the properties of the composite materials studied were not greatly improved over the matrix, it is speculated that if the graphite phase were removed from the reagent, this could in-turn enhance the properties of the material. © 2008, American Scientific Publishers