Metal surface modification by a nanosecond diffuse discharge in nitrogen

The study demonstrates the feasibility of surface modification by a runaway electron preionized diffuse discharge (REP DD) at atmospheric pressures on a nanosecond pulse generator. It is shown that REP DD treatment provides an up to twofold decrease in carbon concentrations in the surface layers of steel and aluminum. It is found that both materials subjected to REP DD are involved in surface oxidation with the result that the oxygen concentration in steel surface layers increases three times and the surface microhardness of the material is enhanced at different depths, whereas the oxygen concentration in aluminum surface layers remains almost unchanged, and the surface microhardness of the material decreases due to the formation of an amorphous oxide layer.