Electrochemical Stability of cpTi with Surfaces Modified by Acid Etching and Aluminum Oxide Sandblasting

Abstract

The aim of this study is to investigate the corrosive behavior of commercially-pure titanium (cpTi) discs as a function of different surface modifications: machined (surface I - control), modified by chloride acid and hydrogen peroxide (surface II), modified by sulfuric acid and hydrogen peroxide (surface III), modified by aluminum oxide sandblasting (surface IV) followed by chloride acid and hydrogen peroxide treatment (surface V) or sulfuric acid and hydrogen peroxide treatment (surface VI). An oral environment with different artificial saliva pHs (3; 6.5 and 9) will be simulated. Additionally, the tests will be conducted in simulated body fluid solution to mimic the blood plasma (pH 7.4). The hypothesis to be tested is that the proposed surface treatments will enhance the corrosion behavior of cpTi when compared with machined surface. Additionally, it is hypothesized that the acidic pH of artificial saliva will reduce the corrosion resistance of cpTi independent of the type of surface modification. In the electrochemical assay, standard tests such as open circuit potential, electrochemical impedance spectroscopy (EIS), and potentiodynamic tests will be conducted in artificial saliva with different pHs and in simulated body fluid solution. The corrosion current density (Icorr), passivation current density (Ipass), corrosion potential (Ecorr), capacitance (Cdl) and polarization resistance (Rp) of the cpTi oxide layer will be determined. Discs' surfaces will be characterized by scanning electron microscope (SEM), atomic force microscope, and their surface roughness will be investigated. Energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD) will be used to investigate the composition of the oxide layer formed on the cpTi surface. Quantitative data will be statistically analyzed at a significant level of 5%.