A novel approach for the formation of Mg(OH)2/MgO nanowhiskers on magnesium: Rapid anodization in chloride containing solutions

In the present work we report on the electrochemical formation towards layers of multiscale MgO nanowhiskers by a two step approach. First, metallic magnesium was anodized under “high-voltage”-conditions in chloride containing ethanol/water mixtures. This results within seconds in the formation of dense areas of magnesium hydroxide nanowhiskers on the surface. The individual as-grown whiskers have a needle tip shape, and a length depending on the growth time of up to 20 μm. The whiskers can be transformed to MgO by a thermal annealing process. To gain more insight into this very rapid growth process, the paper describes the influences of the key parameters of the anodization (pH, ion-concentration, electrolyte composition) and the effect of the thermal treatment on the morphology. All steps were characterized using SEM, EDX, XRD and XPS measurements.