Tribological Performance of Copper Plate Rolling Liquids Under the Synergistic Effect of a Sulfur-Containing Antiwear Additive and Graphene Available to Purchase

In this article, the tribological and rolling performance of rolling liquids formulated by adding modified graphene nanoparticles (MGr) and a thiadiazole derivative (T561) are evaluated. It is shown that when the content of MGr is 1.5%, the average friction coefficient and wear-rate of the rolling liquid are 0.071 and 0.51 × 10⁻⁶ mm³/N·m, respectively, representing reductions of 11.25% and 30.6% compared to the base rolling liquid. Furthermore, under the condition of 90% water content, the average friction coefficient and wear-rate of the 1.0% T561-1.5% MGr composite rolling liquid are 0.077 and 5.11 × 10⁻⁶ mm³/N·m, respectively, with reductions of 31.3% and 74.7% compared to the base liquid. Energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses indicate that this improvement is primarily attributed to the generation of a transfer film composed of sulfide, copper sulfate, copper oxide, and MGr on the copper plate when lubricated by the T561–MGr composite rolling liquid, which effectively reduces direct contact, thereby improving the rolling quality. Rolling tests indicate that the copper plate lubricated by the T561–MGr rolling liquid exhibits a profile roughness (Ra) of 0.150 μm, representing a 48.5% reduction compared to the base rolling liquid. Thus, lubrication with the T561–MGr composite rolling liquid can significantly reduce the roughness of the copper plate.