The materials used in electrical contact applications are constituted of a copper alloy (brass or bronze) electroplated with two coatings, a nickel layer (diffusion barrier) and a gold layer (corrosion barrier). There are some pores in the nickel and gold layers leading to corrosion of the underlying layers. To modify the gold coating microstructure, a laser surface treatment has been undertaken. An excimer laser is used firstly because the photon absorption coefficient is larger in UV range and secondly because the laser beam homogeneity is available for a surface treatment. The purpose of this surface treatment is to suppress the porosity of the gold layer, which is responsible of the corrosion pits, and to smooth the surface as the roughness prevents a correct electrical contact. The effects of the laser treatment are studied according to different surface parameters (roughness of the substrate, thickness of the two successive coatings, a nickel layer and a gold layer). A numerical code is used to simulate the influence of the laser beam parameter on the surface melting. Tests of corrosion are carried out in the humid synthetic air containing low contents of pollutants (NO2, SO2 and Cl-2). The techniques used to control these effects are optical microscopy and scanning electron microscopy (SEM). (C) 2002 Elsevier Science B.V. All rights reserved.