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| Abstract No.: |
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Scheduled at:
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Wednesday, May 05, 2010, Hullet Room 3:00 PM
Biomedical and Polymer Coatings
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| Title: |
Design of experiment analysis of the Sulzer Metco DJ high velocity oxy fuel coating of hydroxyapatite for orthopaedic applications
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| Authors: |
Joseph Stokes* / School of Mechanical & Manufacturing Engineering, National Centre for Plasma Science and Technology, Dublin City University, Ireland
Shahriar Hasan / Materials Processing Research Centre & National Centre for Plasma Science and Technology, Dublin City University, Ireland
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| Abstract: |
High Velocity Oxy-Fuel HVOF has the potential to produce Hydroxyapatite HA (Bio-ceramic) coatings based on its experience with other sprayed ceramic materials; this technique should offer mechanical and biological results comparable to other thermal spraying processes such as plasma spray. Deposition of HA via HVOF is a new venture especially using the Sulzer Metco Diamond Jet (DJ) process, and the aim of this paper was to establish the HVOF?s potential in providing superior Ha coating results compared to Plasma spray, the approved process currently used in orthopaedic implants. In this research, Design of Experiment (DOE) models were developed to optimize the Sulzer Metco DJ HVOF process for the deposition of HA. In order to select suitable ranges for the production of HA coatings the parameters were first investigated. Five parameters (factors) were researched over two levels for: oxygen flow rate, propylene flow rate,air flow rate, spray distance and powder flow rate. Coating crystallinity and purity were measured as the responses to the factors used. The research showed that: propylene, air flow rate, spray distance and powder feed rate had the largest effect on the responses and the study aimed to find the desired optimised settings to achieve high crystallinity and purity of percentages of up to 95%. This research found crystallinity and purity values of 93.8% and 99.8% respectively for a set of HVOF parameters which were improved findings compared to the crystallinity and purity of 87.6 % and 99.4 % respectively found using the FDA approved Sulzer Metco Atmospheric Plasma thermal spray process. Hence a new technique for HA deposition now exists using the DJ HVOF facility. Future research aims to evaluate the biological response to these coatings through in vitro tests.
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