Enhanced Lubricant Property of Flame-Sprayed Aluminum Coatings Additivated by Reduced Graphene Oxide Nanosheets

Flame spraying was applied to prepare aluminum (Al)-reduced graphene oxide (rGO) composite coatings for the first time using ball-milled composite powders. The microstructure, tribological and electrochemical properties of the rGO-Al composite powders and coatings were investigated. Microstructural characterization for the composite powders reveals that rGO nanosheets adhered to Al particle surfaces after milling. Flattening and cold welding phenomena of Al particles were also recognized. The structure evolution of rGO as a function of the time of ball milling was also revealed. The results of coating microstructure investigation show that the rGO nanosheets were uniformly distributed in the coatings after coating deposition. The result of ball-on-disk testing shows that the addition of 0.3 wt.% rGO in the composite coatings brought about significantly enhanced lubricant performance. We believe that the results gained in this research would give insight into producing novel rGO-metal anti-friction materials.