Résumé : For the first time, a unique expert system able to give assistance to designers in surface engineering has been built. Not only is this software able to provide multi-layer coating solutions, but it is also able to rank different solutions according to their technico-economical interest. In addition to its ability to solve corrosion and wear concerns, it is also able to deal with surface finishing properties (like brightness, weldability, electrical conductivity, biocompatibility, …). This paper describes the structure of this expert system together with its main operation principles and future developments.