Preparation of functionally graded bio-ceramic film by MOCVD

摘要

Functionally graded Ca-Ti-O/Ca-P-O films were prepared by MOCVD. The phases, composition and morphology of Ca-Ti-0 and Ca-P-0 films changed depending on the molar ratio of each precursors, total pressure (P_(tot)) and substrate temperature (T_(sub)). CaTiO_3 films in a single phase were obtained at T_(sub) = 973 and 1073 K. CaTiO_3 films prepared at 873 K had a dense and smooth surface, whereas that prepared at T_(sub) = 1073 K had complicated rough surface with a cauliflower-like texture. The graded texture of CaTiO_3 films from columnar to fine grains was advantageous to good adherence for metal substrates. α-TCP and HAp films in a single phase were obtained at T_(sub) = 973 and 1073 K. Both α-TCP and HAp films had a dense and smooth surface. The maximum deposition rate of Ca-Ti-O and Ca-P-O films were 44 and 20 μm/h, respectively, and several 10 times grater than that of sputtering method. Apatite formation rate strongly depended on the surface morphology of film. Apatite formed after 3 days on the CaTiO_3 film, 14 days on the α-TCP film and 6 hours on the HAp film in a Hanks' solution.