Surface Structural–Phase Modification of Structural Steels during Gas Nitriding

ABSTRACT: The formation of a composite nitride layer in an ammonia atmosphere with the addition of carbon– and oxygen–containing gases during gas nitriding is considered. The conditions for the formation of cementite during nitriding of steel and the influence of carbon in the matrix on the release of cementite are given. After oxidation of the nitride layer, modified nitride compositions with stable gradient structural–phase states were obtained.