Cold roll bonding of dissimilar metals (two or more material layers) is a well-known, cold, pressure-welding process and provides great advantages in comparison to single alloys for a variety of applications. It allows various material properties (optical, mechanical, thermal, chemical or electromagnetic) to be combined, which a single material cannot achieve. One example for the application of this technique is the bonding of wear-resistant parts where a high-strength material is bonded onto softer base materials. Depending on the requirement, 3 or 5 layers are no rarity. The manufacturing industry faces the challenge of increasing demands on material characteristics, which can only be satisfied by developing new clad material combinations. In this first of two papers, diffusion phenomena of alloying elements and the corresponding interface-layer formation are the focus of the investigation. In a further paper, the mechanical properties of the investigated material couple will be presented. As a first step, the diffusion profiles after different heat treatments were determined by means of electron probe microanalysis (EPMA) investigations. They provide an insight into the quantitative (line-scans) and qualitative (element-distribution mapping) local chemical composition in the interface region. In the second stage, the diffusion coefficients and activation energies were calculated based on the EPMA results. Finally, the observed interface layers were characterized by means of LOM and SEM pictures which were correlated to the EPMA line-scan results.