Nitrogen uptake by nickel in NH3–H2 atmospheres

Abstract

The incorporation of N into Ni[N] solid solution by gaseous nitriding in NH3-H2 containing atmospheres, corresponding to a nitriding potential rN,0 at the tube furnace inlet, was studied at 450°C. For the encountered low N contents cN (<1 at.-%), validity of Henry’s law is expected, i.e. proportionality of cN with the nitriding potential rN,0 of the gas inserted into the furnace. However, NH3 decomposition in the furnace, even at the temperature considered, which is usually neglected, leads to deviation from this proportionality, i.e. an effective rN<rN,0 operates. A scheme for obtaining the cN(rN) data from the experimental cN(rN,0) data is described.