Proposal on the interface strength evaluation in the coating material of medical materials

Abstract

Bioactive Ti alloy for implant application has been developed by producing thin hydroxyl-apatite (HAp) film on its surface. The interfacial strength between the base metal and the HAp film has to be evaluated to ensure the reliability of the implant, but the method of evaluation is not yet established. In this paper, tensile load is applied to the HAp film on Ti-6Al-4V alloy substrate nominal to its thickness by using a specimen bonded with adhesives. We improve accuracy of this method by preventing adhesive overflow from bonded surface by applying surface active agent thus avoid coverage of the interface between Ti-6Al-4V substrate and HAp film. As a result, fracture occurs at interface between Ti alloy and HAp. It means this method is useful for evaluating interfacial strength between Ti alloy and HAp.