As ceramic materials, the use of hydroxyapatite (HA) in clinical applications is severely limited by its intrinsic poor mechanical properties. The incorporation of some bioinert ceramics is believed to be a way to improve the mechanical reliability of HA matrix. HA coatings with titania addition were produced by using high velocity oxy-fuel (HVOF) spraying process in the present study. The mechanical properties of the as-sprayed coatings in terms of adhesive strength, shear strength and fracture toughness were investigated aiming to reveal the reinforcing effect of the titania addition in HA coatings. Qualitative phase analysis through X-ray diffraction (XRD) showed that mutual chemical reaction between TiO2 and HA occurred during coating formation, from which CaTiO3 was resulted. Totally unmelted titania powders were observed which suggests that the mutual reaction locates at HA/TiO2 splats' interface. Significant influence of coating microstructure on mechanical properties was revealed. As the content of titania in HA coatings reached 20vol%, the adhesive strength decreased largely. As the content of titania reached 30vol%, the further augmentation of the adhesive strength of is possibly resulted from the improved coating microstructure. The fracture toughness exhibited the values of 0.48 Mpa ⋅ m½ 0.60 Mpa ⋅ m½ and 0.67 Mpa ⋅ m½ for pure HA coating, 10vol% TiO2 blended HA coating and 20vol% TiO2 blended HA coating, respectively.

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