2014 Volume 55 Issue 8 Pages 1337-1343
Self-assembled monolayers (SAMs) of stearic acid (SA) film were developed on pure magnesium with heat-pretreatment in order to improve both the corrosion resistance and the bioactivity of pure magnesium. A new method using a high concentration of SA solution (10−1 mol/L) is proposed to reduce the process time of the conventional SAMs methods. The effect of ultrasonic cleaning treatment on SAMs was investigated. Contact angle measurements were employed to evaluate the hydrophobic properties of the SAMs. The corrosion resistance and the bioactivity of the specimens were evaluated under biological conditions (simulated body fluid, 37°C) using potentiodynamic polarization method and long term immersion test. Surface morphology, composition and structure analysis of samples were characterized by the scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) after immersion test. The results showed the corrosion resistance of pure Mg was improved by stearic acid-SAMs and the MgO layer made by heat-pretreatment, the SAMs made in high concentration (10−1 mol/L) of stearic acid solution just for 1.5 h showed better properties than conventional SAMs. Furthermore, ultrasonic cleaning treatment led to the formation of more dense and orderly SAMs and improved the anticorrosion property of SAMs prepared in high concentration of SA solution. Moreover, SAMs-Mg had better bioactivity than untreated magnesium.
