Adhesion fo Hydroxyapatite Layer Prepared by Thermal Plasma Spraying to Titanium or Titanium (IV) Oxide Substrate

摘要

Hydroxyapatite (HAp) was sprayed onto titanium substrates in argon-hydrogen thermal plasma or onto titanium (IV) oxide substrates in argon-oxygen thermal plasma. In the latter case, no adhesive strength by a tensile test could be measured because of high fragility of titanium (IV) oxide. Comparison of the width of peeled-off layers by a scratch test suggested a higher adhesive strength of HAp layers sprayed onto titanium (IV) oxide than onto titaium substrates. It seemed that the surface oxide layer of the titanium substrate would give a positive contribution to adhesion. In both the above experiments, adhesive strength increased with the substrate temperature up to 1130 deg C and the maximum adhesive strength was 19.2 MPa for layers sprayed onto titanium.