HA/YSZ/Ti6A14V Bioactive Gradient Composites Fabricated By Magnetron Sputtering

Bioactive gradient coatings containing HA and YSZ were designed and prepared by RF magnetron sputtering on the Ti6Al4V substrates. In this paper, XRD, FTIR, SEM, AFM and EDS analyses of HA/YSZ gradient coatings were made. Bioactivity of as obtained coatings was revealed by in vitro experiment. The conclusions are obtained from the above works as follows:Hydroxyapatite(HA) powder was prepared by chemical precipitation method. XRD results showed that the HA powders with high purity was obtained. TEM results showed that the morphology of the HA precipitation is needle-like and globe-like with the average size of 43.2nm in diameter.The syntheses of HA target and HA/YSZ targets were studied by hot pressing. Results indicated that the relative densities of all targets were higher than 95%, which could satisfy the request of the RF magnetron sputtering to the target material.RF magnetron sprayed HA/YSZ gradient coating was consisted of amorphous phase and dehydroxylated HA structure. The n(Ca)/n(P) ratio in the surface of as-sputtered coatings was 1.69 which was close to the stoichiometric n(Ca)/n(P) ratio (1.67) of HA. HA/YSZ gradient coating showed a porous structure and a rough surface, which provides the growth conditions for tissue, even to improve the osteal combination ability.The appropriate post-annealing treatment was carried out under suitable atmospheric condition so that the dehydroxylated HA structure was highly crystallized. The surface of HA/YSZ gradient coating was still coarse and uneven with the concave and convex shape after post-annealing treatment. Furthermore, HA/YSZ gradient coating was converted into calcium deficient coating with needle like crystals by post-annealing treatmentThe bonding strength of HA/YSZ/Ti6Al4V composite implant prepared by RF magnetron sputter technique is 51MPa. For sputtered coating, surface roughness of Ti6Al4V substrates was not the key factor which decided the bonding strength. Since there existed chemical reaction between coating and substrate, the bonding strength...