Surface Modification of Anodized Titanium for Calcium Phosphate Coatings

Abstract

The anodization of titanium involves the formation of a thin, dense and compact, oxide layer. In this process the rutile structure of the original titanium oxide is converted into an anatase structure. It is this anatase structure and how it influences the bonding properties of the sol gel coating of hydroxyapatite (HAp) was the main aim of this research project. The titanium samples were anodized in phosphoric acid (H3P04) at varying concentrations with one solution utilizing sulphuric acid (H2S04) in addition to the phosphoric acid. The samples were also anodized at 3 different voltages, l2V, 15V and 20Volts for 30 minutes. Both anodized and unanodized samples were spin coated with alkoxide-derived hydroxyapatite and examined with x-ray diffraction and scanning electron microscopy. The samples anodized utilizing a mixture of phosphoric acid (H3P04)1 sulphuric acid (H2S04) solution were found to produce a more adherent and homogenous HAp coated surface. It is envisaged that this improved anodizing technique could aid the generation of more effective HAp coatings on titanium and titanium alloy orthopaedic and dental implants.