Papers by Author: David S. McPhail

Abstract: Stainless steel (SS) is often used for orthopaedic and dental implants because of its excellent mechanical characteristics. However, from an electrochemical perspective, SS can be susceptible to corrosion-related problems. Inorganic bioactive coatings on SS surfaces are reported to impart corrosion resistance and enhance biocompatibility. In this paper, hydroxyapatite (HA) coatings were developed on SS 316L by an electrophoretic deposition (EPD) technique at applied deposition voltages from 10 to 60 V in an acidic aqueous solution. The present study was performed to optimise the applied voltage required to produce stable HA coatings on SS 316L. Their corrosion resistance in simulated body conditions were investigated using the potentiodynamic polarisation curves. The results of the electrochemical studies revealed that the optimal applied voltage for EPD of HA on SS 316L was 40 V. The polarisation parameters, such as the corrosion potential, breakdown potential and repassivation potential of HA coated materials demonstrated nobler behaviours than the uncoated SS 316L. These results validated the successful formation of stable and protective HA coatings on SS 316L.

Abstract: Glass matrix composites based on NextelTM fibre reinforced borosilicate glass were fabricated. Unidirectional fibres were arranged in two directions with a periodic interspacing sandwiched between two glass slides. XRD analysis and SEM observations proved that the selected process parameters were effective in densifying the composites without significant transparency losses. A geometry based equation was derived to evaluate the expected light transmittance of the composites. ZrO2 coating on Nextel™ fibres, developed by a sol-gel method, was investigated in order to provide a weak bonding at the fibre/matrix interface to promote fibre pull-out during fracture. A developed hybrid sol-gel coating method was employed to form a smooth and crack free coating surface on the Nextel™ fibre bundles. The present composites show potential for applications in architecture and special machinery requiring strong transparent windows.