Process for generating an oxidic protective layer on a high-temperature material moulding

摘要

An oxidic protective layer on mouldings made of low-aluminium high-temperature material, which layer protects the base material against the attack of permeating hydrogen, is produced by the initial generation, especially by a brief immersion treatment in an Al bath and the removal of excess aluminium, of a thin aluminium-containing alloy layer in the metallically bright surface, which is then (a) heated in hydrogen for at least 10 hours at at least 900 DEG C and after cooling (b) is treated at < 700 DEG C for at least 5 to 10 hours in a mixture of steam-containing inert gas with a few vpm of oxygen and finally (c) is heated for at least a day at 900-950 DEG C in a mixture of steam-containing inert gas with hydrogen, having an H2:H2O ratio of approximately 1:1. i