Preparation and properties of wear‐resistant carbonized‐ceramic composite coating on pure aluminum surface

Abstract In this paper, a new composite coating was prepared on the surface of pure aluminum (Al) by combining the micro‐arc oxidation (MAO) technology with the polyethylene glycol (PEG 400) carbonization technology. The composite coating and the single MAO coating were observed by a scanning electron microscope, and an energy‐dispersive spectrometer, finding that the single MAO coating surface with volcano‐like pores and microcracks, was covered by the carbonized layer of the composite coating where the overall coating thickness was around 19.5 µm, including 17.5 µm of inner MAO coating. The material properties of the composite coating were characterized by X‐ray diffraction and X‐ray photoelectron spectroscopy. The wear resistance of the composite coating was tested under dry friction conditions, finding that the wear width on the composite coating surface was 909.6 µm only, which was around 55.7%, 50.4%, and 58.2% of those for pure Al substrate, single carbonized coating, and single MAO coating, respectively. Then the comprehensive wear resistance of the composite coating was explored under different sliding speeds and lubrication mediums. Finally, the wear‐resisting mechanism of the composite coating was discussed, concluding that the composite coating could effectively reduce adhesive wear and abrasive wear of the Al substrate.