| Affiliation: | (1) Department of Mettallurgy and Materials Engineering, University of Connecticut, CT 06269, USA;(2) Department of Biomedical Engineering, School of Aerospace Mechanical and Mechatrnoic Engineering, University of Sydney, NSW 2006, Australia;(3) Graduate School for Biomedical Engineering, University of New South Wales, NSW 2052, Australia;(4) School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia |
| Abstract: | Electrophoretic deposition (EPD) is a low cost flexible process for producing HA coatings on metal implants. Its main limitation is that it requires heating the coated implant in order to densify the HA. HA typically sinters at a temperature below 1150 C, but metal implants are degraded above 1000C. Further, the metal induces the decomposition of the HA coating upon sintering. Recent developments have enabled EPD of metathesis-synthesised uncalcined HA which sinters at  1000C. The effects of temperature on HA-coated Ti, Ti6Al4V, and 316L stainless steel were investigated for dual coatings of metathesis HA sintered at 1000C. The use of dual HA coatings (coat, sinter, coat, sinter) enabled decomposition to be confined to the  undercoat (HA layer 1), with the surface coating decomposition free. The tensile strength of the three metals was not significantly affected by the high sintering temperatures (925C < T < 1000C). XRD/SEM/EDS analyses of the interfacial zones revealed that 316L had a negligible HA:metal interfacial zone (1  m) while HA:Ti and HA:Ti6Al4V had large interfacial zones (>10 m) comprising a TiO2 oxidation zone and a CaTiO3 reaction zone. |
