Hydrothermal Modification of Products Fabricated by Electron Beam Melting

Abstract

Electron beam melting (EBM) method is one of the free-form fabrication techniques that enable near-net-shape manufacturing of complex three-dimensional, porous, and graded products, and is expected to facilitate the development of new methods for manufacturing biomaterials that could be used for hard-tissue substitutes. Titanium and its alloys have been used widely as biomaterials for hard-tissue substitutes because of their excellent mechanical properties and biocompatibility. However, the osteointegration of these materials is less than that of bioactive ceramics. Therefore, various surface-modification techniques have been developed to improve the osteointegration. The simplest way is to synthesize bioactive ceramic films on the surface of titanium or its alloys. The purpose of the present work was to synthesize a bioactive TiO2 film on Ti-6Al-4V (hereafter, abbreviated as Ti-64) substrates fabricated from powders using the EBM method and treated by a combination of chemical and hydrothermal treatment. Ti-64 plates fabricated by the EBM method were chemically treated with a H2O2/HNO3 aqueous solution under appropriate conditions. The plates were then hydrothermally treated with a NH3 aqueous solution. TiO2-gel films were produced by chemical treatment with a H2O2/HNO3 aqueous solution on the surface of a Ti-64 substrate. Anatase-type TiO2 films with high crystallinity were synthesized by the hydrothermal treatment of the TiO2-gel films.