Effects of in-situ incorporation of h-BN nanosheets, low-melting nanoclays and corrosion-inhibiting stannate on plasma electrolytic oxidized AZ31B Mg alloy

Boron nitride nanosheets and organo-modified nanoclays are in-situ incorporated into the plasma electrolytic oxidation (PEO) layer fabricated on AZ31B Mg alloy. A stannate-based corrosion inhibitor with an inherent self-repairing effect is also tested. The modified PEO/Mg alloys are characterized for micro/nano-scale surface morphology and roughness, phase and microstructure, elemental composition and distribution, surface wettability and are studied for mechanical properties, bonding strength and electrochemical corrosion resistance. The results suggested fruitful benefits of the combined in-situ incorporation on PEO/Mg alloy's corrosion resistance. The hard ceramic nanomaterials with high melting points, such as boron nitride, could be more effectively incorporated into the PEO layer with the co-deposition of low-melting nanoclays. Besides, an inhibitor such as stannate in the PEO deposition bath could make an effective protective conversion layer, providing an additional protective effect without significantly interfering with the PEO layer formation. The results provided could be beneficial in developing better PEO/Mg alloys for industrial applications.