Titanium-implanted CaTiO3 films and their changes in Hanks' solution

Titanium-implanted CaTiO3 film was prepared and then characterized by x-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS) before and after immersion in Hanks' solution for 7 days. An as-prepared specimen contained a small amount of Ar implanted during sputtering, although the pressure was as low as 10(-4) Torr. Even though Ar convolution increased with an increase in the relative Ti ion dose, most of the convoluted Ar was not from the Ar gas used for Ti ion production but rather was from the Ar gas used for sputtering the CaTiO3. During Ti implantation, the CaTiO3 films were ion-etched by Ti ions. The composition of the CaTiO3 film was not changed to any great degree by the Ti implantation, however its properties changed considerably. After immersion in Hanks' solution, the thickness of the specimen not implanted with Ti decreased the most whereas the [Ca]/[P] ratio, which was nearly unity before exposure, decreased significantly, becoming 0.23 on the Ti-implanted specimen prepared at 200 W and 0.13 on the Ti-implanted specimen prepared at 50 W. It was also observed by XPS that the ratio [Ca]/[P] was similar to1.9 for all Ti-implanted specimens after immersion in Hanks' solution for 7 days. judging from the binding energies of Ca 2p(3/2) and P 2p electrons and the [Ca]/[P] ratio, it was suggested that a hydroxyapatite-like substance had formed on the surfaces of the Ti-implanted specimens after immersion in Hanks' solution. Copyright (C) 2003 John Wiley Sons, Ltd.