Effect of magnesium fluoride coating on corrosion behaviour of magnesium alloy

Magnesium and its alloys are explored as potential biomedical materials for being lightweight, bio-absorbable, and having attractive biological properties. A major hindrance for their use is their high corrosion rate, in particular when exposed to body fluids. This study aims at suppressing the corrosion rate of a magnesium alloy (Mg1.0Ca) by coating it with magnesium fluoride (MgF2). The coating was done by immersion of the workpiece in hydrofluoric acid solution. For comparison, pure magnesium was also coated with MgF2. The MgF2 coated magnesium exhibits significantly lower corrosion rate than pure magnesium. The MgF2 coated magnesium alloy shows even lower corrosion rate. The MgF2 coating works in inhibiting corrosion on magnesium alloy Mg1.0Ca. The corrosion inhibition was also contributed by other compound formed during reaction between Mg1.0Ca and hydrofluoric acid and the alloy in Mg1.0Ca.