A method for generation of defined nitrating layers on iron and iron alloys in an oxygen-containing gasatmosphaere and arrangement for producing and maintaining the therefor required output gas mixtures

摘要

Defined nitriding layers are produced on Fe or Fe alloys in an O2-contg. gas atmos. of NH3 which is partly, e.g. 20-70%, dissociated, at 590 degrees C, by admixing NH3 nitriding medium in initial condition with O2, in amounts such that after total reaction of O2 with NH3 and/or H2, from partial dissociation of NH3, the partial press. ratio of steam formed to remaining H2 does not exceed a given partial press. ratio PH2O/PH2. This partial press. ratio PH2O/PH2 can assume values which still enable a neutral behaviour, at given nitriding temps., corresponding to limiting curve for oxidn. and reduction of Fe at 590 degrees C.