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Showing 1 to 20 of 22 for “"Metal on metal"”.
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The role of metal ions in metal-on-metal total hip replacement
Abstract Role of Metal Ions in Metal on Metal Total Hip Replacement Metal-on-metal (MoM) total hip replacement (THR) offered theoretical advantages of decreased wear and increased functional outcomes. MoM bearings have been associated with sterile inflammatory masses and significant soft tissue …
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Growth and properties of metal-on-metal nanostructures: Ag on Cu(110) and Co on Ag(110)
… nanostructures have a diverse array of applications and show novel phenomena that arise from the exotic physics exhibited in reduced dimensions. We have investigated two nano-structured systems in order to gain insights into the dynamics of their nucleation, growth and have observed striking …
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Friction and lubrication behaviour of metal-on-metal and ZTA ceramic-on-CFR PEEK hip prostheses. Friction and lubrication behaviour of metal-on-metal hip resurfacing and ZTA ceramic heads versus CFR PEEK cups wiith various diameters and clearances using serum-based lubricants with various viscosities.
… hip joint in healthy people has a very low friction with very little (or no) wear. It works as a dynamically loaded bearing and is subjected to about 1-2 million cycles of loading per year. The applied load is the body weight which is tripled when walking and even higher during other activities …
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The Effect of Particle Surface Area to Volume Ratio on Ion Release from CoCr Spheres
… artificial prosthesis. Of these arthroplasties, metal-on-metal type implants represent an increasing usage percentage. Metal-on-metal implants are selected largely for their low volumetric wear rate, durability, and resistance to corrosion. In spite of these advantages, little is known concerning …
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Friction and lubrication behaviour of hip resurfacing metal-on-metal and ZTA ceramic on CFR peek implants with various diameters and clearances. Friction and lubrication behaviour of hip resurfacing Co-Cr-Mo and zirconia toughened alumina ceramic heads against carbon fibre reinforced poly-ether-ether-ketone cups with various diameters and clearances have been investigated using serum-based lubricants.
… of the UHMWPE cups as a result of high friction between the articulating surfaces leading to osteolysis and implant loosening with revision surgery becoming inevitable in more active patients. Tribology plays an important role in developing the design, minimizing wear and reducing friction of …
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A Force Sensor Array for Space Applications
… for force feedback and spatial awareness of contact in harsh environment applications, such as space servicing, has been unsatisfied due to the inability of current sensor technology to resist environmental effects. In this work, capacitive sensors based on a porous polymer-ceramic composite …
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The corrosion of CoCrMo alloys for biomedical applications
… of years. They are now frequently used for the metal-on-metal hip resurfacing joints due to their high corrosion and wear performance. The present project was carried out to investigate the feasibility of taking electrochemical measurements from hip resurfacing joints whilst articulating in a …
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Wear at high sliding speeds and high contact pressures
Metal on metal wear at high sliding speeds and high contact pressures results in the melting of one or both of the sliding solid bodies due to heat generated at the contact interface. Understanding the influence of sliding speeds, contact pressures and material properties on wear rates is important …
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Corrosion and trib-corrosion behaviour of metallic orthopaedic implant materials
Since the introduction of medical implants into human bodies, corrosion and wear have been regarded as key issues for their long-term durability. There has been a recent renewed interest in the use of large diameter metal-on-metal (MoM) hips, primarily because of the reduced volumetric wear …
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A laboratory simulation of adhesive wear of high speed reciprocating components in water powered mining equipment
… sliding wear test rig was used to examine the metal on metal surface interactions of materials under consideration for application in water powered stoping equipment. The suitability of this test rig was investigated by implementing a test programme covering self-mated stainless steel and …
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Immune system involvement in metal hip implant failure
Osteoarthritis (OA) is the most common debilitating disease, especially in the elderly.Total Hip Replacement (THR) is a last resort treatment for hip OA and Metal-on-Metal (MoM) THR was used commonly for its durability. While this is an effective treatment for many, around 12% of hip implants were …
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Atomic and electronic structure of bulk intermetallic and heteroepitaxially grown surface alloys
… to this broken symmetry in the reduced dimension of the surface, the energetic of the surface also differs from the bulk counterpart. Reconstruction, charge redistribution, and surface alloying are phenomena that minimize the surface free energy. Surface properties of scientifically and …
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Corrosion Dynamics of Cobalt-Chromium Alloy F-75 Powder
The increasing usage of metal-on-metal joint replacements consisting of a cobalt-chromium-molybdenum alloy requires increasing concern regarding the inevitable generation of metallic wear debris. Patients with these joint replacements exhibit elevated concentrations of cobalt and chromium ions …
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Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance
Bimetallic nanocatalyst often shows enhanced performance where the key lies not only on the overall composition but more importantly, is related to the specific atomic arrangement of the two metal elements on the and near surface regions. In order to make the most out of bimetallic nanocatalyst, it …
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Tribological and Structural Characterisation of Ceramic on Metal Hip Replacements
A tribological investigation of ceramic on metal hip replacements was carried out using in vitro wear testing methods. Two ceramic materials, pure alumina and an alumina matrix compound (zirconia toughened alumina (ZTA)), were articulated against as-cast CoCrMo alloy cups. The diameter was changed …
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Development and application of a lubricant composition model to study effects of oil transport, vaporization, fuel dilution, and soot contamination on lubricant rheology and engine friction
Engine oil lubricants play a critical role in controlling mechanical friction in internal combustion engines by reducing metal-on-metal contact. This implies the importance of understanding lubricant optimization at the piston ring-cylinder liner interface. Lubricating oil composition varies along …
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The effect of clearance upon friction and lubrication of large diameter hip resurfacing prosthesis using blood and combinations of bovine serum with aqueous solutions of CMC and hyaluronic acid as lubricants.
… clotted blood) instead of synovial fluid. Blood contains large molecules and cells of size ~ 5 to 20 2m suspended in plasma and considered to be a non-Newtonian (pseudoplastic) fluid with density of 1060 Kg/m3 and viscosity ~ 0.01 Pas at shear rates of 3000 s-1 (as obtained in this work). The …
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Design, Material and Surgical Assembly Effects on Fretting Corrosion Behavior of Modular Tapers in Orthopedic Implants
<p>Mechanically assisted crevice corrosion (MACC) has become a significant problem in the orthopedic device industry, particularly in modular devices with metal-on-metal (MoM) tapered interfaces. Oxide film abrasion, leading to fretting corrosion in the presence of a crevice, accelerates the …
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Abrasion-corrosion of cast CoCrMo in simulated hip joint environments
Metal-on-metal (MoM) hip joint replacements have been increasingly used for younger and more active patients in recent years due to their improved wear performance compared to conventional metal-on-polymer bearings. MoM bearings operate at body temperature within a corrosive joint environment and …
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