The technology of preparing green coating by conducting micro-arc oxidation on AZ91D magnesium alloy

Micro-arc oxidation was applied to AZ91D magnesium alloy by taking K2Cr2O7  as the colouring salt in the silicate system. It was shown that the green coating obtained through performing micro-arc oxidation on magnesium alloy consisted of Mg, Mg2SiO4 , MgO, and Mg2SiO4  based on analysis of X-ray diffraction (XRD), and scanning electron microscopy (SEM). Among which, Mg2SiO4 was the colouring salt; there were something in the lamellar, pit, and convex forms found on the surface of the coating. The coating consisted of a porous, and a compact, layer from the outside to the inside. As demonstrated, the colour of the coating depended on the K2Cr2O7 concentration: it became gradually deeper with the addition of K2Cr2O7 and the increasing micro-arc oxidation time. The corrosion resistance and hardness of the green coating were greater than that of the matrix.

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Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę (zadania 2017).