Alloying of austenitic steel surface with zirconium using nitrogen compression plasma flow

In this study, the effect of a nitrogen compression plasma flow on the microstructural and mechanical properties, as well as on the elemental and phase compositions of a Zr/chromium-nickel 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. The samples were characterized by scanning electron microscopy, Auger electron spectroscopy, X-ray diffraction, and energy dispersive X-ray analyses, and subjected to a Vickers microhardness test. The findings showed the formation of a surface modified layer alloyed by Zr with the thickness of up to ∼12 μm. The modified layer contains α- and γ-iron-based solid solutions, the Fe23Zr6 intermetallic compound, and ZrN and Cr2N nitrides due to nitrogen diffusion. The microhardness of the modified layer increased by a factor of ∼2.