Characterization of the interface in the plasma sprayed HA coating/Ti-6Al-4V implant system

The authors objective was to characterize the plasma sprayed HA/Ti-6Al-4V interface using traditional techniques (tensile testing, EDXA) as well as novel fracture toughness testing and high resolution analytical TEM examination. In addition to evaluating as-sprayed specimens, the effect of post-plasma spraying heat treatments on interface bonding was assessed. It is shown that in all as-sprayed batches, failure occurred relatively cleanly at the metal ceramic interface. Fracture toughness data suggest that this implant system is particularly sensitive to defects at the interface, though absolute toughness values cannot be assigned to this interface due to some necessary initial assumptions. The weakly-bonded coating region incorporated into the specimen design appeared not, however, to affect toughness determinations.