Thus, such changes at the surface of the working electrode occurred during PDP test might cause difficulties in evaluation of the original anticorrosion tendency of the samples. This point of view is consistent with other reports [25,43, 44], claiming PDP test is unsuitable to compare the corrosion performance of Mg, because of dynamic processes taking place on the polarized surface and in the adjacent electrolyte. Therefore, the EIS results discussed in section 3.4.2 provide a more reliable estimate of corrosion resistance for the studied samples.