Bio-ceramics Coatings Prepared By Suspension Plasma Spraying

Preparing bio-ceramics coatings on titanium alloy（Ti6Al4V） surface, which cancombine the excellent mechanical property of metal substrate and the good biocompatibilityof bio-ceramics materials, now is one of the hottest research spots on the clinicalapplication of artificial bone implants. Hydroxyapatite （HA） is the most mature studiedbio-ceramics material at present, which has excellent biocompatibility and bone-inducedability. However, as the large mechanical property difference between Ti6Al4V and HA,the bonding strength between substrate and coating is low, which is very hard to approach20MPa; The dissolution speed of HA in body fluid is fast, which is easily lead to coatingdissoloved as a result of the stress failure. Fluorapatite （FA） can promote calciumphosphate mineralization and crystallization; also the dissolution speed of FA is slowerthan HA, so the participating of FA can improve the coating property.In this article, TiO2-FA-HA composite structure coatings were coated on Ti6Al4Vsubstrate, which was prepared by Micro-arc Oxidation pre-treatment, using SuspensionPlasma Spraying method. X-ray Diffraction（XRD） and Fourier Infrared AbsorptionSpectrometry（FTIR） were used as analyzing the phases and chemical compositions;Scanning Electron Microscopy（SEM） were used as analyzing the surface morphologies andmicrostructure of the coatings; The bonding strength of the coatings was analyzed byTensile Machine.The main content of this article studied in the preparation of hydroxyapatite suspensionmethod and the influence caused by Suspension Plasma Sprayed process parameters oncoating properties. The appropriate concentration of suspension was5wt%ofhydroxyapatite and0.5wt%ten-water sodium pyrophosphate （Na₄P₂O₇·10H₂O） as thedispersing agent. The Zeta potential of HA suspension was-33.8mV,the average particlesize distribution was76.02nm. The Zeta potential of FA suspension was-34.0mV,theaverage particle size distribution was70.17nm. The bonding strength of HA coating was24.2MPa. The bonding strength of FA coating was26.8MPa. Coatings appeared CaO，α-TCP, β-TCP and other amorphous phase; through the800℃heat after-treatment can improve the crystallinity. The results showed that the coatings combined with goodcrystallinity and bonding strength.