Use of synchrotron radiation in the analysis of strains near the interface between a plasma-sprayed hydroxyapatite coating and a Ti-6Al-4V substrate

Abstract

Plasma sprayed hydroxyapatite coatings on titanium alloy are often used in prosthetic implants. The metallic substrate gives the implant good mechanical strength which is combined with good biocompatibility and osteointegration of the ceramic coating. However there is sometimes a failure of the implant, and this failure is often located at the interface between the titanium alloy and the hydroxyapatite coating. Knowledge about the strains in the materials near the interface seems to be an important step in understanding why the failure occurs. Synchrotron radiation, using Beamline BM16 at the European Synchrotron Radiation Facility (Grenoble, France), has been used to measure local strains near the interface, down to 10 μm in resolution, between a plasma-sprayed hydroxyapatite coating and a titanium alloy substrate. The influence of sand blasting and shot peening on the strains from the surface to the depth of the titanium alloy before coating has been investigated, along with the strains around the interface from the surface of the hydroxyapatite to in-depth in the titanium alloy.

Key Words:

• Synchrotron
• Strain
• Interface
• Coating
• Hydroxyapatite
• Titanium
• Biomaterial