Bonding Strength Test and Biological Evaluation of Plasma Sprayed HA-based Composite Coatings

摘要

To improve the bonding strength of HA coating, several HA-based composite coatings (HA/Ti, HA/ZrO_2, HA/ZrO_2·SiO_2 and HA/NiCr composite coatings) have been fabricated via atmospheric plasma spraying. The bonding strengths of fabricated specimens were tested by ASTM C-633 method. The bioactivity of composite coatings was evaluated by examining carbonate-containing apatite formation on their surfaces in simulated body fluid (SBF). In vitro cell cultures were carried out to examine the biocompatibility of composite coatings. The results obtained revealed that the addition of metal or ceramics in HA improved the bonding strength of coating significantly except HA/ZrO_2·SiO_2 composite coating. In SBF test, all of these four coatings were covered by carbonate-containing apatite after immersed in SBF, indicating good bioactivity for composite coatings. The results of cell cultures produced the testimony of excellent biocompatibility for the coatings except that HA/NiCr composite coating possessed cytotoxicity. By comprehensive survey of bonding strength, bioactivity and biocompatibility, HA/Ti and HA/ZrO_2 composite coatings were candidates of prospective biocoatings.