Ion nitrided AISI H13 tool steel Part I – Microstructural aspects.

In the present paper, five different operating conditions of a plasma nitriding process on annealed AISI H13 were investigated. A systematic variation of processing parameters such as gas mixture, time of processing and current density has been carried out in order to study their effect on microstructure. X-ray diffraction, microhardness testing and scanning electron microscopy techniques coupled with semiquantitative energy dispersive X-ray analysis were used to characterise the nitrided samples. The results revealed that the current density during plasma processing has a considerable influence on both the compound layer formation and depth of the diffusion zone. Also, it has been shown that the geometrical configuration of the workload may affect the uniformity of the diffusion zone, giving rise to the presence of heterogeneous nitrogen distribution zones along it. [ABSTRACT FROM AUTHOR]