*2.2. X-ray Fluorescence and X-ray Diffraction Characterisation*

Elemental analysis of the fabricated substrates was performed three times and averaged using a BRUKER TITAN S1 X-ray fluorescent (XRF) handheld analyser (Coventry, UK) to ensure that the bulk components in the manufactured substrates match the composition standards. This was done by placing the substrate on a working station then adjusting the lens of the XRF device vertically on the substrate before starting the measurements, which required 10 s to complete for each single measurement. Moreover, X-ray diffraction (XRD) analysis was performed using a 9 kW Rigaku SmartLab, Tokyo, Japan, XRD device that utilizes a CuKα X-ray source at a diffraction angle of 2θ and an incidence beam angle of 0.02◦. This was done in order to identify the Bragg's peaks of each element contained within the substrates and to define the phase of the stainless steel alloy used. The diffraction scanning angle ranged from 20◦ to 80◦, with a scanning rate of 2 ◦/min.
