ABSTRACT

In this study, the effect of a nitrogen compression plasma flow on the microstructural, mechanical, and tribological properties, as well as the elemental and phase compositions of a Zr/austenitic steel system, has been investigated. The Zr/steel system was exposed to a single pulse of the compression plasma flow or to a series of pulses of different energies. The plasma pulse duration and discharge current were 100 µs and 80 kA, respectively. The samples were characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analyses, and subjected to Vickers microhardness and friction tests. The findings showed the formation of a surface modified layer alloyed by Zr depending on the absorbed energy value was about 12−20 µm. An increase in both the number of pulses and absorbed energy density provides a more uniform zirconium distribution in the modified layer. The surface microhardness and wear resistance of the treated samples increased by factors of 1.6 and 5.4, respectively. The modified layer contains α- and γ-iron-based solid solutions, the Fe₂₃Zr₆ intermetallic compound, and ZrN and Cr₂N nitrides due to nitrogen diffusion.