Interfacial characterization of plasma-spray coated calcium phosphate on Ti–6Al–4V

Abstract

Microstructural characterization was performed on plasma-spray coated calcium phosphate and its interface with Ti–6Al–4V using scanning and transmission electron microscopy. The amorphous calcium phosphate phase was found near the coating/substrate interface, usually in between the crystalline hydroxyapatite grains and the Ti–6Al–4V substrate. The presence of the amorphous calcium phosphate and the channels extending from the interface to the coating surface was attributed to the low interfacial bond strength in a physiological environment. There was an indication of titanium diffusing into the amorphous regions. However, no reaction phases were found between the coating and the Ti–6Al–4V substrate. In the coating area remote from the interface, no intergranular amorphous calcium phosphate phase was observed. The microstructure of the Ti–6Al–4V substrate near the interface was observed to be affected by heat generated during plasma spraying. © 1998 Kluwer Academic Publishers