Oxidation and corrosion behaviors of Mg-based nanoparticles

Various Mg-based nanoparticles were prepared by evaporating bulk magnesium in the atmospheres of Ar, Ar+N2 and CH4, respectively. The formations, phases, morphologies, thermal properties and corrosion behaviors of these kinds of nanocomposite particles were investigated by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), thermogravimetric-differential thermal analysis (TG/DTA) and potentiodynamic polarisation scan (PPS). It is shown that the Mg-based nanoparticles produced in Ar and Ar+N2 atmospheres have hexangular crystal habits with particles' sizes ranging from 50 to 400 nm, while the nanoparticles produced in CH4 atmosphere have amorphous carbon out layers with particles' sizes among 20-100 nm. TG/DTA results show that two-steps oxidation process can be confirmed for all samples, which may be attributed to the oxidations of out layer and core of nanoparticle. The CH4 atmosphere-prepared nanoparticles exhibit better corrosion resistance properties due to its peculiar carbon doping.