COMPOSITION PERFECTIONNEE DE REVETEMENT DE SURFACE

摘要

The invention concerns a surface coating composition, in particular for heat-exchanger tubes in incineration installations, designed to operate in a high temperature oxidising environment (A). Said composition comprises in major part iron for crystallising along a centred cubic structure which has a high atomic diffusion speed. It comprises chromium (Cr) capable of migrating to the surface (CS) of the coating to combine with oxygen (O) and form a oxide layer (1) preventing oxygen from entering the coating volume (MV). Said oxide layer (1) is permeable to molybdenum (Mo) and niobium (Nb) which is contained in the inventive composition, said species being then capable of migrating to the surface (CS) and form with the chlorine (C1) in the environment (A) a surface layer (2) of chlorides preventing chlorine from entering the volume. Such a coating provides efficient protection against corrosion.