A passivation method for the metallic surface of a nickel and iron-based superalloy which is used as the constituent material of reactor or furnace walls is described, in which the superalloy is coated on at least one of its surfaces which comes into contact with a corrosive atmosphere containing either hydrocarbons at high temperature or containing oxidizing gases at high temperature, with at least two successive layers resulting from successive chemical vapour deposition of its one or more constituent elements, the external phase, resulting from chemical vapour deposition of at least one silicon compound and the layer(s) deposited between the superalloy surface, and the external layer resulting from chemical vapour deposition of at least one of a metal or metalloid.