An AZ31 magnesium alloy coating for protecting polyimide from erosion-corrosion by atomic oxygen

A continuous and uniform AZ31 magnesium alloy coating was deposited by magnetron sputtering to protect flexible polyimide substrate (Kapton HN) from atomic oxygen (AO) erosion-corrosion in low earth orbit. The AO erosion yield of the coated Kapton was determined to be 8.87 × 10−26 cm3 atom−1 after exposure to AO fluence of 1.47 × 1021 atoms cm−2, about 34 times lower than that of blank Kapton. XPS analysis results showed that an oxide layer of MgO formed on the surface of the coating after AO exposure, which is the main reason for the enhanced AO erosion-corrosion resistance of the AZ31 Mg-alloy coating.