Patent ID: 6024893
Filing Date: 2000-02-15
Classification: C23C,F27D

Abstract:
A method of controlling the nitriding potential of a nitriding furnace, comprising the steps of:providing a source of ammonia supply gas containing ammonia and oxygen;delivering a portion of the ammonia supply gas to a dissociator;delivering another portion of the ammonia supply gas to the nitriding furnace;dissociating the ammonia supply gas within the dissociator to create a dissociated ammonia carrier gas;dividing said dissociated ammonia carrier gas into a first portion and a second portion;delivering said first portion of said dissociated ammonia carrier gas to said nitriding furnace;delivering said second portion of said dissociated ammonia carrier gas to an oxygen probe as a reference gas for said oxygen probe;sensing the oxygen partial pressure differential within the oxygen probe predisposed in said furnace atmosphere;producing a signal correlation of said oxygen partial pressure differential relative to the nitriding potential; andcontrolling the ratio of ammonia supply gas to dissociated ammonia carrier gas at the inlet of the nitriding furnace in response to said signal correlation.