Mass transfer and doping during electrolyte-plasma treatment of cast iron

Abstract

The surface and subsurface layers of cast iron articles upon electrolyte-plasma treatment (EPT) were studied for the first time by a combination of methods, including Rutherford backscattering, elastic recoil detection analysis, X-ray diffraction, optical metallography, and microhardness measurements. It was found that tungsten and copper ions are incorporated into the surface layers of the metal. Total thickness of an EPT-hardened layer is about 3 mm, the maximum hardness (up to 7000 MPa) being observed at a depth from 1 to 2.5 mm. The X-ray diffraction analysis (i) shows that the EPT-hardened layer comprises a mixture of α and γ phases, (ii) indicates the formation of a fine-grained martensite structure with high dislocation density (above 10¹² cm⁻²) and an oxide (FeO) phase, and (iii) reveals mass transfer involving the doping elements (W and Cu).