The work concerns study of hydrogen distribution on surface of selected metals with the use of glow discharge mass spectrometry (GDMS). Hydrogen was intentionally introduced in the form of titanium hydride (TiH₂) to copper, nickel and titanium samples. The metal samples were doped with TiH₂ in two ways.

One set of samples concerns the application of a suspension of titanium hydride in various solvents to the surfaces of these metals.

The second set of samples includes metal samples to which inclusions were introduced in the form of a mixture of compressed TiH2 with copper powder. In this case, several mixtures with different concentrations of TiH₂ in copper were used.

The prepared sets of samples were analysed using GDMS model SMWJ-01 apparatus equipped with a glow discharge source of an internal diameter of 4 mm, powered by a DC voltage of 1.2 kV. This apparatus uses a quadrupole mass spectrometer SRS-300. Additional equipment is the xyz high-vacuum translation stage which allows in situ movement of the analyzed sample with respect to the GD source [1].

As a result of the analysis, we obtain 7 x 7 mm surface maps using the pixel-by-pixel rastering method (14 px x 14 px). During the mapping procedure, ion currents are recorded, including: H⁺, H₂⁺, H₃⁺, Ar⁺, ArH⁺, ⁴⁸Ti⁺, ⁵⁸Ni⁺ and ⁶³Cu⁺.

We present discussion of the obtained results. In some cases we observe so called “hydrogen effect” caused by the emission of hydrogen gas into the working gas in the glow discharge cell [2, 3]. In such cases, the quantitative assessment of the surface hydrogen distribution is difficult.

Discussion of the results, including the “hydrogen effect”, also concerns the mapping of selected samples by another analytical technique of secondary ion mass spectrometry (SIMS). Hiden Analytical SIMS Workstation was used, and the studied surfaces were bombarded with a beam of 5 keV primary O₂⁺ ions.

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[1] Konarski, P., Miśnik, M., & Zawada, A. (2016). Two-dimensional elemental mapping using glow discharge mass spectrometry. Journal of Analytical Atomic Spectrometry, 31(11), 2192-2197
[2] Bengtson, A., & Hänström, S. (1999). The influence of hydrogen on emission intensities in GD-OES consequences for quantitative depth profile analysis. In Proceedings of the 5th International Conference on Progress in Analytical Chemistry in the Steel and Metals (pp. 47-54).
[3] Hoffmann, V., Uhlemann, M., Richter, S., & Pfeifer, J. (2021). Calibration capacity of hot-pressed hydrogen standards for glow discharge optical emission and mass spectrometry. Spectrochimica Acta Part B: Atomic Spectroscopy, 176, 106039.