Acid pretreatment of titanium implants

The purpose of this study was to evaluate the effectiveness of several methods of cleaning titanium surfaces as pretreatment for surface modifications by analyzing the chemical interaction of three acids, such as Na2S2O8, H2SO4 and HCl, followed by rinsing with acetone or ultrapure water. Chemical evaluation, using X-ray photoelectron spectroscopy (XPS), and mechanical evaluation, using nanoindentation, were employed. XPS revealed that an untreated Ti surface consisted of carbon- and nitrogen-containing contaminant and titanium oxide layer on metallic titanium substrate. The method involving the combination of HCl and acetone was the most effective of all the methods investigated. Such a combination most effectively reduced values of contamination parameters C/Ti and N/Ti, as well as the intensity of the titanium oxide component in Ti 2p spectra. Chlorine was barely detected from the surface treated with HCl in any concentration. Sulfur from the residual S2O82− or SO42−, however, was detected from the samples treated with either Na2S2O8 or H2SO4. The S/Ti values depended on concentration of the acidic solution. In addition, nanoindentation measurements revealed that Youngʹs modulus of the surface treated with 0.1– HCl was not significantly different from that of an untreated surface (p>0.05). Consequently, the HCl/acetone treatment is proposed as an excellent decontamination method for the surface preparation process of Ti.