The Influence of Plasma Treatment on the Corrosion and Biocompatibility of Magnesium

Abstract

In our study, plasma surface modification was employed to tailor the surface properties of magnesium in terms of surface chemistry, topography, and wettability. For two sets of samples, the plasma treatment involved two steps using two different gases (hydrogen and oxygen), while one set of samples was treated with one step only using oxygen. X-ray photoelectron spectroscopy (XPS) was applied to determine the surface composition, oxidation state of the elements, and the thickness of the surface oxide layer on the Mg samples after different plasma treatments. The surface morphology was characterised using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The wettability was analysed by measuring the static water-contact angles and the corrosion was evaluated using potentiodynamic measurements. The interaction of the live cells with the differently modified Mg surfaces was evaluated in terms of biocompatibility using MG-63 cells (human bone osteosarcoma cells). We have shown that a plasma surface treatment significantly decreased the carbon content and the formation of a 15–20-nm-thick MgO layer was observed. This improves the corrosion resistance, while the biocompatibility was retained, compared to the untreated Mg. A plasma surface treatment is therefore an important step in the development of novel surfaces with improved corrosion resistance for magnesium in biomedical applications.

Electrochemical behaviour of sputter-coated titanium films on AZ31 magnesium alloy

“…From the ratio and from Figure 8(b), it can be observed that the peak area of 529 eV is mostly small, barring the exception of T150 sample which has a ratio of 0.6, signifying the presence of oxidised TiO 2 . Mg-1s core level spectra are shown in Figure 8(c), which shows a peak at 1304 eV representing Mg from the substrate [68][69][70] and the peak features remain the same in all three cases. The XPS spectra for various elements collected from the corroded areas of Ti-coated AZ31 are shown in Figure 9 for comparison.…”