Abstract
Degradable magnesium alloy is one of the most promising scaffolding materials, which can provide a temporary opening into a narrowed arterial vessel and will progressively disappear thereafter. But its clinical application is not very extensive as it still has the problem of non-uniform degradation and rapid degradation rates, especially at the initial stage, which need further study to overcome. In this study, the adsorption properties of solution on the magnesium oxide, which is the first step of magnesium alloy reaction, is investigated by molecular dynamics simulation at different temperatures and flow velocities. The body fluid is simplified to NaCl solution. The number density of solution perpendicular to the MgO surface is calculated to analyse the adsorption capacity, the self-diffusion coefficient is researched to measure the adsorption rate. At same time, the effects of temperature and flow on the adsorption properties of solution are also clarified. The results show that there exist solution films at the surface of metal, and the solution can be divided into two zones: adsorption zone and free zone according to the density profile. As temperature increases, the adsorption rate of solution is improved while the adsorption capacity has little change. What’s more, it’s found that flow can accelerate adsorption, but decrease the amount of adsorption. This study improves the understanding of adsorption characteristics of NaCl solution from the microscopic point of view, which plays an important role in understanding the corrosion process of MgO.
