Effects of Nitriding Subsequent Titanaliting of Steels

Résumé

The paper presents the results of nitriding in partially dissociated ammonia of the pure technical iron, respectively 34CrAlMo5 steel after titanaliting in powdery solid medium, with direct reference on the growth kinetics of the layers, the phase composition and the morphology of the resulting layers. Thermodynamics was anticipated and experimentally demonstrated that the layers of titanium aluminide formed on the surfaces of the two metallic materials considered do not constitute barriers to nitrogen diffusion during the nitriding process, but actively participate in the formation of simple or complex nitrides of the two elements, titanium and aluminum. On the other hand, in the presence of these layers, the flux of nitrogen atoms is slightly diminished with repercussions on the dimensions of the structural components of the layer. The conclusion of the experimental research was that the role of titanaliting prior to nitriding is to increase the proportion of the hardening phases in the surface layers of thermochemically processed metal products after nitriding.