PROCESS FOR PRODUCING A PROTECTIVE COATING ON METAL WALLS SUBJECT TO ATTACK BY HOT GASES, ESPECIALLY FLUE GASES

摘要

A process for producing a protective coating on walls subject to attack by hot gases in a predetermined temperature range, which are made of metal and a predetermined basic material, in combustion plants, heat exchangers or similar installations, in which a powder of metallic, carbide, oxycarbide or silicide materials or mixtures thereof are applied to the metal walls using the plasma jet process. The invention proposes that: a) the surface of the wall is roughened; b) the basic material of the wall is activated; and c) immediately afterwards the powder is applied at room temperature and in atmospheric conditions by the plasma jet process; being d) the composition of the powder selected beforehand so that the stress as a function of the temperature in the unstressed state (at room temperature) found with the aid of coefficients of heat expansion of the basic material and test-pieces for the transition region between the basic material and the applied coating produced from various powders gives tensile stresses of between 50 and 800 N/mm2 and preferably between 500 and 800 N/mm2, which is reduced to 0 or exhibits slight compression stresses in the predetermined temperature range.