Effect of the hydroxyapatite particle size on the properties of sprayed coating

Preparation of hydroxyapatite (HA) coatings by supersonic atmospheric plasma spraying (SAPS) method on carbon/carbon (C/C) substrate has great potential application in biomedical fields. In this paper, surface morphology, particle distribution, phases, thermogravimetric analysis (TG)/differential scanning calorimetric (DSC) tests, bonding strength and bioactivity of the sprayed coatings fabricated by using different HA particle sizes including micron and nanoscale are discussed. The practical implication of the results shows that the micro-crack on nanoscale HA coating reduces. The crack width and decomposed phase also lower. Bonding strength between sprayed nanoscale HA coating and C/C substrate is increased by 63.80% compared with that of sprayed micron HA coating and the coating still has biological activity in stimulated body fluid (SBF) solution.