Sinter-coating method for the production of TiN-coated titanium foam for biomedical implant applications

Titanium foams for biomedical implant applications were produced by space holder technique. Novel sinter-coating method was used for the production of TiN layer on foams in order to enhance wear and corrosion resistance. In literature, Ti compacts were sintered in vacuum or argon atmosphere and then expensive and complex coating processes were carried out on sintered specimens. In this study, the titanium foams were sintered in N2 atmosphere at 1200 °C. Biocompatible TiN layer was coated on foam surface by gas nitriding simultaneously during sintering. Sinter-coating combines sintering and TiN coating in one step by sintering the green specimens in N2 atmosphere. This reduces cost of operation and time. In addition, alkali treatment was used to activate surface of foams for partially induce a bioactive bone-like apatite to enhance bioactivity. Alkali treatment was performed by soaking the foams in NaOH solution and then heating at 600 °C. After alkali treatment, foams were immersed into simulated body fluid to induce a bone-like apatite layer on foam surface.