Preparation of Functionally Graded Bio-Ceramic Film by MOCVD

Abstract

Functionally graded Ca-Ti-O/Ca-P-O films were prepared by MOCVD. The phases, composition and morphology of Ca-Ti-O and Ca-P-O films changed depending on the molar ratio of each precursors, total pressure (Ptot) and substrate temperature (Tsub). CaTiO3 films in a single phase were obtained at Tsub = 973 and 1073 K. CaTiO3 films prepared at 873 K had a dense and smooth surface, whereas that prepared at Tsub = 1073 K had complicated rough surface with a cauliflower-like texture. The graded texture of CaTiO3 films from columnar to fine grains was advantageous to good adherence for metal substrates. -TCP and HAp films in a single phase were obtained at Tsub = 973 and 1073 K. Both -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 m/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 CaTiO3 film, 14 days on the -TCP film and 6 hours on the HAp film in a Hanks’ solution.