Synthesis of α-Al2O3–graphene composite: a novel product to provide multi-functionalities on steel strip surface

We successfully prepare a composite retaining crystalline structure of α-Al2O3 and graphene using a dry (no chemical) planetary ball milling technique. The composite was then coated efficiently on steel substrate via a non-transferred plasma torch. Good adhesion with almost uniform microstructural distribution of α-Al2O3–graphene composite (4 wt%) on steel substrate was shown in FESEM study. It was remarkably observed that α-Al2O3–graphene (4 wt%) composite coated on steel substrate improves its surface properties exhibiting hardness and Young’s modulus of 370 ± 11 VHN and 292 ± 22 GPa, respectively. This sample is also found to show significant high electrical conductivity of ~ 6.6 × 106 S/m. This composite can be an alternate coating to hard chrome coating, carburisation and nitriding with added advantage of surface conductivity.