Superlubricity enabled by graphene nanocomposite film on carbon-coated AISI 1045 steel

• Cost-effective biotreatment using Manihot esculenta-based graphene nanocomposites on AISI 1045 steel at 500–900 °C. • Macroscale superlubricity with ~0.0015 friction coefficient and ~88% wear reduction achieved at 900 °C after 5 hours of treatment. • The hardness increased from 2.69 GPa (untreated) to 3.00 GPa treated at 900 °C. • Graphene films protected surfaces by reducing adhesive and abrasive wear through graphene oxide layers and embedded nanocrystals. • Innovative deposition technique supports a circular economy by transforming waste into durable and efficient industrial coatings. This paper presents a low-cost and innovative method for treating high temperature biowaste to create an ultra-low friction carbon-based coating on AISI 1045 steel. Utilizing carbon from Manihot esculenta biowaste, graphene variants were deposited on substrates at 500 °C and 900 °C. The microstructure and mechanical/tribological properties were studied pre- and post-treatment. These include Vickers hardness and wear characteristics that were measured with a ball-on-disk wear tester. Increasing treatment temperature and time resulted in high substrate hardness. The graphene variants were characterized using Raman spectroscopy with discernible trends D and G band trends. The I 2D /I G and I D /I G intensity ratios varied as the treatment conditions changed. Electron backscatter diffraction, X-ray diffraction, optical, scanning electron, and atomic force microscopy provided insights into phases and microstructural features. Tribological tests showed remarkable ∼95.20 % reduction with a superlubricious coefficient of friction of ∼0.0015 and ∼88 % decreased wear rate for substrates treated for 5 h at 900 °C. The graphene platelet and multiwalled defective structures on the substrates transformed into graphene oxide and graphene nanocrystals providing the needed solid lubrication. The underlying mechanisms are discussed before elucidating the implications of the result for the design of rigorous, novel carbon coatings for frictionless and ultralow-wear surfaces in a circular economy.