Structure, mechanical performance and electrochemical characterization of plasma sprayed SiO2/Ti-reinforced hydroxyapatite biomedical coatings

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Title: Structure, mechanical performance and electrochemical characterization of plasma sprayed SiO2/Ti-reinforced hydroxyapatite biomedical coatings
Author(s): Morks, M. F.; Fahim, N. F.; Kobayashi, A.
Abstract: For achieving an excellent bioactivity and mechanical properties, silica and titanium-reinforced hydroxyapatite composite coatings were deposited onto 304 SUS substrate by using a gas-tunnel plasma spraying system. A commercial HA powder of average size 10–45 μm was blended with fused amorphous silica and titanium powders with HA:SiO2:Ti wt.% ratios of 75:15:10 respectively. The mixed powders have been plasma sprayed at various plasma gas flow rates (Ar) of 120, 140, 160 and 170 l/min. The morphologies and structure of the resulting coatings were investigated by scanning electron microscope, X-ray diffraction and electron dispersive spectroscopy. Hardness, abrasive wear resistance and adhesive bonding strength properties of the as-sprayed composite coatings were investigated. Silica and titanium provide reinforcement via increasing the bonding strength of HA particles and abrasion resistance. A heat treatment for the sprayed coatings was carried out at a temperature of 650 °C for 2 h in ambient oxygen and the change in the phase structure was analysed by X-ray diffraction. The results showed a formation of TiO2 (rutile) phase due to titanium oxidation at 650 °C. On the other hand, the heat treatment enhanced the crystallinity of HA coating by transferring the non-apatite tri-calcium phosphate phase into apatite phase. The corrosion resistance measurement by polarization method confirmed the improvement of corrosion resistance of the composite HA/SiO2/Ti coatings compared with the pure HA. However, the annealed samples showed lower corrosion resistance compared with as-sprayed samples.
Publication type: Journal article
Source: Applied Surface Science, Vol. 255, no. 5, part 2 (Dec 2008), pp. 3426-3433
Publication year: 2008
FOR Code(s): 0204 Condensed Matter Physics; 0912 Materials Engineering
Keyword(s): Abrasive wear; Adhesion; Biomaterials; Corrosion; Hardness; HA/SiO2/Ti composite; Heat treatment; Plasma spraying
Publisher: Elsevier B.V.
ISSN: 0169-4332
Publisher URL: http://dx.doi.org/10.1016/j.apsusc.2008.09.088
Peer reviewed