Effect of surface roughness on electron work function of AZ31 Mg alloy and their correlation

Highlights: • The effect of surface roughness on the EWF of AZ31 Mg alloys was investigated. • The change of the local electrostatic field at rough surface resulted in the increase of the EWF. • The EWF was linearly increased with the increased roughness. • A microcapacitor model was used to explain the relationship between the EWF and surface roughness. Effect of surface geometrical configurations on electronic behaviors of various light alloys are of both fundamental and practical significance. In this study, the effect of surface roughness on the electron work function (EWF) of AZ31 Mg alloys was investigated by scanning Kelvin probe and theoretical simulation. The experimental results indicated that the surface roughness had an important effect on the EWF, and the EWF was linearly increased with the increased roughness. It was mainly in that the change of the local electrostatic field near the rough surface confined the movement and transfer of the electrons, resulting in the increase of the EWF. Based on the microcapacitor model, the linear relationship between the EWF and the surface roughness was reasonably explained, which was well consistent with the experimental data.