Influence of beam power on the surface architecture and corrosion behavior of electron-beam treated Co-Cr-Mo alloys

Abstract

We present results of the influence of the electron beam power on the structure, surface roughness, and corrosion of electron-beam surface-treated Co-Cr-Mo alloys. The structure of the samples is characterized using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Atomic force microscopy (AFM) is used for the evaluation of the surface topography. The corrosion resistance is studied by an electrochemical test. The EBST process leads to a transformation in the phase composition, from a double-phase structure of ε and γ to a single-phase gamma structure. Higher values of the beam power lead to the elimination of pores and other structural defects, as well as a formation of preferred crystallographic orientation. The EBST causes a slight increase in the surface roughness and significantly more symmetrical surface topography. Also, the corrosion resistance was greatly improved after electron-beam surface treatment with higher values of the electron beam power.