Textured hydroxyapatite interface onto biomedical titanium-based coatings

Hydroxyapatite (HAP) bioceramic coatings grown onto titanium-nitride (TiN) buffer layers by the aerosol-gel procedure present interfaces with a preferred growth orientation. These coatings were crystallized at 800degreesC and subsequently etched to ease the study of the interface by Auger electron spectroscopy depth profiling. Ion beam milling was applied to cross-section samples to analyze the interface structures using transmission electron microscopy. At the interface, the HAP crystals showed a <002> orientation. It was shown by Auger electron spectroscopy depth profiling that 0 atoms diffuse into the nitride inter-layer, indicating that the formation of 0 channels in the HAP structure is the driving force inducing the textured film. The outstanding biocompatible properties of both the materials and properties of their interface suggest that HAP/TiN structures are particularly well suited for endo-prosthetic applications. (C) 2003 Wiley Periodicals, Inc.