Author Foo, Hui Yueh
Title Concurrent reactive sputtering deposition of biocompatible hydroxyapatite on Ti6A14V alloy.

Academic Exercise (B.Sc. Hons.) National Institute of Education, Nanyang Technological University

Year 2002
Supervisor Xu, Shuyan
Call no. QC176.8.S72 Foo

Biocompatible hydroxyapatite (HA) films have been prepared on orthopaedic Ti6A14V alloy by concurrent reactive FW magnetron sputtering of a HA-Ti target in the plasmas of pure argon and argon-water gas mixtures. The films were characterized using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), secondary ion mass spectroscopy (SIMS) and X-ray diffraction (XRD). XPS results show that the Ca/P ratio is close to stoichiometric value of HA and applied bias was found to drastically affect the Ca/P ratio. The XPS. FTIR and SIMS data revealed the presence of OH and PO4 phases in the film The XRD pattern showed that the deposited film contains mainly crystalline calcium oxide phosphate (4CaO.PlOs) and elevated substrate temperature improved crystallinity of the HA film.

The reaction processes have been monitored by means of in-situ optical emission spectroscopy (OES) and quadrupole mass spectroscopy (QMS). OES spectra showed that radicals exist in the working plasma and time-based scans of selected species exemplified the influences of bias voltage, FW power and gas flow-rate on excited species in the plasma. QMS demonstrated the augmentation of the partial pressure contributed by OH related species with the introduction of water vapour into the chamber. Scratch test showed strong interface bonding strength at substratelfilm layer with critical load around 4 N. Finally, preliminary cell culture test using COS7 cell line proved that the film has excellent biocompatibility.