In this study, a new approach for modification of surfaces with the help of cathodic arc plasma and its bias voltage dependent interaction with the substrates is described. As an example, alloying and surface modification of aluminium-iron alloys (with iron contents of 0.3 and 1 wt.%) with a cathodic arc plasma of copper is given. The effect of successively applied bias voltages of - 150 V and - 1000 V was investigated on the resulting micro structural surface features of the alloys. Surface modification processes were performed below and above 500 degrees C. In the experiments conducted below 500 degrees C, the modified surface predominantly consisted of Al2Cu intermetallics, accompanied with a small amount of AlCu intermetallics and at-aluminum solid solution. However, in experiments conducted above 500 degrees C, melting and resolidification of the copper deposited substrate surface took place at - 1000 V and - 150 V bias voltages, respectively. A eutectic-like microstructure, containing alpha-aluminum, Al2Cu phases, and iron containing ternary structures were obtained. It was found that the enrichment of iron in the surface took place through the enhanced role of the process on the diffusion of iron from bulk to the surface. (C) 2009 Elsevier B.V. All rights reserved.