Enhancement of adhesion bonding between titanium metal and electrodeposited calcium phosphate

A novel hydroxyapatite/rutile coating was prepared on a titanium substrate. Initially, an amorphous calcium phosphate coating layer was electrochemically deposited on a Ti substrate. The surface morphology, chemical composition and phase identification of the coatings were investigated by the X-ray diffraction and scanning electron microscopy associated with an energy dispersive spectrometer. Annealing at 700°C for 3 hrs. transforms the amorphous calcium phosphate layer into well-crystallized hydroxyapatite (HAP) and the Ti metal surface into rutile. The developed HAP/rutile composite surface layer became denser and better adhering with the substrate than the initially formed amorphous calcium phosphate. The adhesion bond strength and the hardness of the coating were extremely raised by thermal annealing.