In automotive and aerospace fields, the use of lightweight materials is required. Magnesium and its alloys combine a low density with high mechanical properties and excellent thermal conductivity. However, those materials suffer from low corrosion and wear resistances. The combined action of corrosion and wear is also critical for these materials. Tribocorrosion of magnesium alloy AZ31 has been investigated with reciprocal sliding wear as a function of the applied load in dry and wet (NaCl) conditions. The study shows that the main wear mechanisms were adhesion, abrasion, and oxidation in dry sliding wear while no adhesion was found in wet sliding wear. Corrosion of the worn surface occurs also in wet sliding wear. It is interesting to notice that wear is less pronounced in wet sliding wear than in dry sliding wear due to the natural lubrication of the NaCl electrolyte. Only severe conditions, high normal load, and wet conditions bring magnesium AZ31 alloy in filiform corrosion.

In the present study, Mg-Al layered double hydroxide (Mg-Al/LDH) was synthesized on the surface of AZ31 Mg alloy substrate via in-situ hydrothermal treatment. Synthesis parameters were changed to determine their effect on the lateral size of LDH. For this purpose, etching in nitric acid and anodizing in sodium hydroxide solution were performed as surface pretreatments. Moreover, the influence of LDH solution pH (10 and 11) on the lateral size of LDH coating was investigated. Morphology, chemical composition, and crystalline structure were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The corrosion resistance of the coatings was investigated by H₂ measurements, salt spray, and electrochemical impedance spectroscopy (EIS). Moreover, the epoxy coating was applied on the best anti-corrosive LDH sample for assessing the compatibility and effectiveness of LDH on the corrosion properties of the substrate with the epoxy layer. At pH = 11, the lateral size of LDH was smaller than samples at pH = 10. In addition, small-sized LDH, as well as LDH/epoxy coating, revealed enhanced corrosion protection.