Plasma Spraying of Hydroxyapatite Tanya Levingstone and Dr. Lisa Looney Materials Processing Research Centre, Dublin City University, Dublin 9, Ireland National Centre for Plasma Science

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Plasma Spraying of HydroxyapatiteTanya
Levingstone and Dr. Lisa LooneyMaterials
Processing Research Centre, Dublin City
University, Dublin 9, IrelandNational Centre for
Plasma Science Technology, Dublin City
University, Ireland
Research Initially adaptations of a basic
Hydroxyapatite system will be considered and
subsequently optimum combinations of composition,
bond coat and post spray treatment will be
identified in order to significantly improve the
quality of the biocoatings. Comprehensive
characterisation of the coatings will be carried
out in order to relate powder and process
parameters to coating properties.
Introduction Bioceramics have proven to be
attractive materials for repairing and replacing
body parts due to their biocompatibility. In
many applications bioceramics are used in the
form of bulk materials of a specific shape.
However in loading bearing applications their
inherent brittleness requires them to be used as
a coating material on a tougher substrate.
Hydroxyapatite (HA) is a bioceramic that has a
composition similar to that of bone. As well as
improving biocompatibility, it encourages the
ingrowth of bone and thus can be used as a method
of fixation for implants such as total hip
replacements and dental implants. Plasma spraying
is the most common means of applying HA coatings
to implant devices. It employs a plasma, or
ionised gas, to melt the ceramic particulate and
to carry it onto the surface of the substrate.
1 The plasma spraying process features complex
plasma-particle interactions that can result in
significant process variations that often
adversely affect process repeatability 2 .
Figure 2 Typical Plasma Spray System 4
Figure 1 Coated Implant Bone Interface 3
Project Aims There is currently a poor
understanding of how coating deposition process
variables influence phase composition, structure
and chemical composition of coatings, which in
turn affect in vivo performance factors including
bioresorption, degradation, bone apposition and
adhesion. The project aims to improve the
understanding of the structure-property-process
relationship to produce improved coatings vital
in functional critical applications, such as
bioengineering.
References 1 Larry L. Hench June Wilson
(editors), An Introduction to Bioceramics, World
Scientific Publishing Co., Singapore, 1993. 2
J.R. Fincke, W.D. Swank, R.L. Bewley, D.C.
Haggard, M. Gevelber, D. Wroblewski, Diagnostics
and control in the thermal spray process, Surface
and Coatings Technology, 146 147 (2001) 537-543
3 Atlanta Health Pages Online
www.healthpages.org (Accessed 05 01 04) 4
Sulzer Metco Online www. Sulzermetco.com
(Accessed 05 01 04)