High-resolution transmission electron microscopy investigation of gradient ceramic-metal interface in the system of hydroxyapatite/titanium

High-resolution transmission electron microscopy was used to investigate the interface of ion beam assisted deposited (IBAD) hydroxyapatite coating and Ti substrate to provide an atomic level picture of the atomic intermixing interface. The interfacial layer is mainly a strongly defective Ti crystalline background, with nanosized amorphous phases composed of Ca, P, O and Ti elements immersed in it. A structural model of the atomic intermixing interface was proposed in terms of the experimental data. The possible mechanism for the adhesion enhancement by the interfacial mixing layer is thought to be the gradient evolution of both the structure and component of the interfacial phases and the bonding among the atoms of both substrates and coatings.