Calibration of X-ray Diffraction Measurements for Depth-selective Structural Analysis of Two-layer Samples

Authors S.N. Danilchenko1 , O.V. Kochenko1, A.N. Kalinkevich1 , A.O. Stepanenko2 , Ye.I. Zinchenko1, P.S. Danylchenko3, I.Yu. Protsenko2

1Institute of Applied Physics, NASU, 58, Petropavlivska St., 40000 Sumy, Ukraine

2Sumy State University, 2, Rymsky-Korsakov St., 40007 Sumy, Ukraine

3Institute of Physics, Faculty of Science, P.J. Šafárik University, 9, Park Angelinum, 04154 Košice, Slovak Republic

Issue Volume 13, Year 2021, Number 2
Dates Received 24 February 2021; revised manuscript received 15 April 2021; published online 20 April 2021
Citation S.N. Danilchenko, O.V. Kochenko, A.N. Kalinkevich, et al., J. Nano- Electron. Phys. 13 No 2, 02037 (2021)
PACS Number(s) 61.05.cp, 61.72.Dd
Keywords X-ray diffraction (19) , Radiation absorption, X-ray penetration depth, Steel (3) , Coating (35) , Copper (8) , Glancing-incidence geometry, Polychromatic radiation.

In the metal structures that are subjected to significant mechanical and radiation loads during their operation, structural alterations occur, which are unevenly distributed over the depth of the material. Materials with a modified surface, including thin coatings and multilayers, are equally challenging objects for structural studies. The development of methods for depth-selective layer-by-layer X-ray diffraction diagnostics is a nontrivial task aimed at controlling the effective depth of the collection of structural information. The most developed approaches to date include: (a) asymmetric (glancing-angle) geometry and (b) the use of primary radiation with different penetrating power. In both cases, calibration procedures with coatings or two-layer systems of known thickness are required to determine the thickness of an effectively reflective layer. In this work, we have studied the possibilities of X-ray diffraction examinations of steel and iron samples with a thin (micron) copper coating. The thickness of the copper coating was estimated from the intensity decrease of the iron substrate’s diffraction lines. With the use of asymmetric (glancing-incidence) measurements, the conditions for the disappearance of lines from the substrate were established, which made it possible to estimate with acceptable accuracy the thickness of the steel layer participating in the formation of the diffraction pattern. The method of the depth-differentiated estimation of the structural characteristics of the "interface" and conditionally "bulk" regions of the α-Fe substrate by using polychromatic cobalt radiation is tested. The limitations of this approach and the possibility of its application to a wider range of steels are discussed. The considered aspects of X-ray diffraction studies of model systems of the "steel-coating" or "steel-modified surface" type are important in the study of surface radiation-stimulated structural alterations in steels of power engineering.

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