STUDIED CHANGES IN THE WORK FUNCTION IN ANNEALING STAINLESS STEEL IRRADIATED BY ARGON IONS

Authors & Affiliations

Ruhljada N.Ja., Visheratin R.K.
Obninsk Institute for Nuclear Power Engineering, Obninsk, Russia

Abstract

Investigation of the interaction of radiation with matter is the basis of predicting the behavior of material in the radiation field and its performance. Austenitic steels are widely used in nuclear and thermonuclear technology, in structures and components that work in the radiation field. Therefore, the study of phenomena occurring during irradiation of these steels is of considerable interest. Steel samples (12X18H10T - GOST grade, 321 - AISI) irradiated in the accelerator with argon ions were studied. Irradiation parameters were as follows: 400°C - sample temperature, 25 kV - accelerating voltage, 50 µA - beam current, 63 min - exposure time, vacuum of 2·10-5 torr. Thermionic emission microscope, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction analysis were used. Work function of the irradiated steel - 4.43 eV and the non-irradiated steel - 3.67 eV were measured using thermionic emission microscope. Work function decreases in the annealing process down to a value of 3.82 eV after 40 minutes of annealing. XPS spectrum of the irradiated specimen annealed at 1400 K for 20 minutes showed a large amount of manganese. The thickness of manganese-rich layer was only 30 Å. The high concentration of manganese on the surface of the sample after heating can be explained by the diffusion of manganese from the heated backside surface to the front side surface of the sample and its segregation. We assume that in the process of heating the sample manganese accumulates on the surface and therefore determines the work function of the sample. According to the literature the work function of manganese is 3.83 eV. This corresponds to a work function obtained after 40 minutes of annealing in thermionic emission microscope. Presumably irradiation with argon ions and heating of the sample leads to the enrichment of the surface layer of steel with manganese. It corresponds with XPS results and the measured work function of samples.

Keywords
thermionic emission microscope, X-ray photoelectron spectroscopy, work function, stainless steel

Article Text (PDF, in Russian)

References

UDC 621.039.531

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants", issue 2, 2014