Energy Dispersive X-ray (EDX) measurements technique and analysis of the experimental results

Organization of hydrogen energy technologies training No. ESF/2004/2.5.0-K01-045 Main organization - Lithuanian Energy Institute Partner - Vytautas Magnus University

I was attending in training program on EDX measurements technique and analysis of the experimental results in the Metallurgic Physics Laboratory, in Poitiers University, France. 2005.09.18 - 2005.10.09

Outline of the presentation: EDX technique EDX analytical methods Analysis of the experimental results Conclusion

EDX technique (1) Energy dispersive x-ray spectroscopy (EDX or EDS) is a chemical microanalysis technique used together with a scanning electron microscope (SEM). The EDS technique detects x-rays emitted from the sample during bombardment by an electron beam to characterize the elemental composition of the analyzed volume.

Origin of Characteristic Line Spectra in an Atom EDX technique (2) When the surface sample is bombarded by the SEM's electron beam, inner shell electrons of sample atoms can be ejected. If this happens, electrons from higher energy levels go to the inner shells causing the emission of high energy photons in the X-ray range. Origin of Characteristic Line Spectra in an Atom

EDX technique (3)

EDX analytical methods Qualitative analysis - the sample x-ray energy values are compared with known characteristic x-ray energy values to identify the elements in the sample. Quantitative analysis – shows the amount of each identified element in the sample. Elemental Mapping Line Profile analysis

EDX spectrum for Alloy 600

Typical applications of EDX Corrosion evaluation Rapid material alloy identification Small component material analysis Coating composition analysis

Experimental results The aim of this work was to calculate chemical composition using EDX technique of deposited and hydrogenated Mg-Ni and Mg-Al thin films.

Experimental technique: fabrication of nanocrystalline MgNi and MgAl thin films materials using magnetron sputtering; hydrogenation of these thin films in high hydrogen pressure and temperature; EDX measurements of these films.

Parameters of deposition and hydrogenation Substrates: quartz and stainless steel (Alloy 600) Hydrogenation: Pressure – 8 bar Temperature – RT - 250 °C Hydrogenation duration – 1- 6 hours Thin film deposition: Co-deposition of MgNi (MgAl) films Substrate temperature – 100-300°C Film thickness – 1 - 3μm

Experimental results (EDX) Mg-Ni film :t=5min., IMg = 0.7 A, INi = 0.3 A Top on the film Ni layer : t = 5sek., INi = 0.3 A Mg film :t=5min., IMg = 1 A   Edge of the film (%) Middle of the film Next edge of the film O 22 24 22.7 Mg 78 76 77.3   Edge of the film (%) Middle of the film Next edge of the film O - Mg 65.7 67.5 69.5 Ni 34.3 32.5 30.5 Alloy 600 substrate Alloy 600 substrate

Experimental results (EDX) Mg-Al film :t=5min., IMg = 0.7 A, IAl = 0.5 A Top on the film Ni layer : t = 5sek., INi = 0.3 A Mg-Al film :t=5min., IMg = 0.7 A, IAl = 0.5 A Top on the film Ni layer : t = 5sek., INi = 0.3 A   Edge of the film (%) Middle of the film Next edge of the film O 70.1 66.4 70.5 Mg 19.6 22 19.3 Al 10 11.4 Ni 0.3 0.2   Edge of the film (%) Middle of the film Next edge of the film O 9 12 18.5 Mg 74.9 73.1 66.5 Al 15.2 14.1 13.5 Ni 0.9 0.8 1.5 Quartz substrate Alloy 600 substrate

Experimental results (EDX) Mg-Al film :t=3min., IMg = 0.7 A, IAl = 1 A Top on the film Ni layer : t = 5sek., INi = 0.3 A Hydrogenation: PH2 = 8 bar, T = 150 0C, t = 5 h Mg-Ni film :t = 5min., IMg = 0.7 A, INi = 0.3 A Top on the film Ni layer : t = 5sek., INi = 0.3 A Hydrogenation: PH2 = 8 bar, T = 250 0C, t = 1 h   Edge of the film (%) Middle of the film Next edge of the film O - Mg 52.4 51.8 52.7 Al 46.7 47 45.7 Ni 0.9 1.2 1.6   Edge of the film (%) Middle of the film Next edge of the film O 54.5 56 56.3 Mg 37.2 37.1 36.6 Ni 18.3 6.9 7.1 Alloy 600 substrate Alloy 600 substrate

Experimental results (EDX)   Edge of the film (%) Middle of the film Next edge of the film O 48.3 46.9 49.3 Mg 36.2 37.2 35.5 Al 15.2 15.7 15 Ni 0.3 0.2 Mg-Al film :t = 5 min., IMg = 0.7 A, IAl = 0.5 A Top on the film Ni layer : t = 5sek., INi = 0.3 A Hydrogenation: PH2 = 8 bar, T = 60 0C, t = 5 h Quartz substrate

Conclusions EDX is an elemental identification technique that uses X-rays emitted from samples to identify elemental species. During the analysis of my experimental work I used quantitative method, which helps to measure the amount of each element in the sample. EDX measurements proved that the elements (Mg, Ni, Al) in our as deposited Mg-Ni and Mg-Al thin films are distributed homogenously. The difference in amount of each element is only few percent. EDX measurements show that we have oxygen in our samples, but also Ni could be as barrier for the formation of oxides.