*2.2. Coating Characterization*

Scanning electron microscope (SEM) MAIA3 (TESCAN, Brno, Czech Republic) was used for surface morphology and cross-sectional examinations. EDS system by (Oxford instruments, Abingdon, UK) with an X-MaxN detector was applied for elemental analysis detection. The phase analysis of the coating was detected using the X'Pert Pro diffractometer (PANalytical B.V., Almelo, the Netherlands) with Cu<sup>α</sup> radiation (λ = 1.542Å) at the grazing incidence mode (grazing angle of 3◦) with a 2θ range from 20 to 70◦ (step size of 0.03◦) at 40 kV and 40 mA.

Coating elemental analysis was also examined by particle induced X-ray emission (PIXE) method by 1.7 MV Pelletron accelerator equipped with SuperSilicon Drift Detector, X-123 SDD (Amptek Inc., Bedford, MA, USA) positioned at 45◦ to the beam (I~4.3 nA with a nominal diameter of 1.5 mm). 2.017 MeV 4He<sup>+</sup> <sup>±</sup> 1 KeV beam was used to collect spectra. The samples were coated by carbon in order to prevent charge effect during irradiation. GUPIX software (University of Guelph, ON, Canada) was used for the PIXE data analysis.

Light scattering measurements were performed using XploRA ONE™ Raman confocal microscope (HORIBA Scientific, Piscataway, NJ, USA) using 532 nm laser excitation line and a constant power of 20 mW.
