Optimization of Steel-Surface Hardening by Carbon Nanostructures Followed by Treatment with High-Intensity Energy Sources

The effect whereby a steel surface is modified by its covering with a nanocarbon material followed by fast electron- or laser-beam irradiation is studied. The initial material is low-carbon steel. Soot produced via the thermal sputtering of graphite electrodes in an electric arc with the subsequent extraction of fullerenes is used as the nanocarbon coating. Due to the fact that nanocarbon-coated samples are irradiated with a 60-keV electron beam, the material microhardness enhances considerably. The dependence between the microhardness and the irradiation energy is nonmonotonic and reaches its maximum (about 600 ± 20 HV) under the condition that the electron-irradiation energy is 460 J/cm² and the intensity is 1.53 kW/cm². This corresponds to a fourfold increase in the microhardness. Electron-beam irradiation of the treated surface is accompanied by a 1.5–2-fold decrease in the friction coefficient. Experimental results are compared with data obtained under laser irradiation of the nanocarbon-coated steel surface.