Influence of plasma electrolytic oxidation on fatigue performance of AZ61 magnesium alloy

The effect of plasma electrolytic oxidation (PEO) on the fatigue of AZ61 magnesium alloy has been investigated under high cycle conditions in air and 3.5% NaCl solution. PEO employed an alkaline pyrophosphate–silicate–fluoride electrolyte, with an offset square waveform, a frequency of 50 Hz, and current density of 130 mA cm−2. The PEO treatment led to reductions in the fatigue limit by 38% in air and by 56% in 3.5% NaCl solution. The reduction of the fatigue limit is attributed to cracking of the coating, roughness of the alloy/coating interface, corrosion and influences of Al–Mn particles.