Formation of Bioactive Titanium Coatings on Titanium Substrate by Reactive Plasma Spraying

Abstract

A simple treatment method using radio-frequency reactive plasma spraying was studied to induce bioactivity of titanium (Ti) coatings. Ti coatings were sprayed on Ti substrates using a thermal plasma of Ar containing 1-6% N₂ and/or O₂ at 16 kW. Composition change of coating′s surface during soaked in a simulated body fluid (SBF) was examined by micro FTIR and thin film XRD. Ti coatings prepared with Ar-O₂ and Ar-N₂-O₂ plasma formed apatite after 3 days of soaking in a simulated body fluid (SBF). In the XRD patterns for both Ti coatings, minute peaks ascribable to TiO₂ (anatase and rutile) were commonly observed. On the other hand, composition change of coating′s surface cannot be observed for Ti coating sprayed with pure Ar and Ar-N₂ plasma after 7 days of soaking in SBF. Ti coatings with Ar-N₂-O₂ plasma gave excellent adhesion to substrate, whereas Ti coatings with Ar-O₂ plasma gave poor adhesion.