Leo 1550 fe sem

The morphology characterization of the samples were performed by scanning electron microscopy (SEM) using a ZEISS LEO 1550 FE-SEM at an accelerating voltage of 7 kV. For the HRTEM analysis, the samples were scratched onto lacey carbon grids and observed using a JEOL 2010F at the Canadian Centre for Electron Microscopy (Hamilton, Ontario, Canada). The surface chemical composition analysis was performed by X-ray photoelectron spectroscopy (XPS) analysis using a multi-technique ultra-high vacuum imaging XPS microprobe spectrometer (Thermo VG Scientific ESCALab 250) with a monochromatic Al-Ka 1486.6 eV X-ray source. Raman analysis was performed with a 50x objective, and the spectra were acquired with a laser wavelength of 633 nm at a power of 0.1 mW. For the electrochemical oxidation, a Gamry Potentiostat (Series 300) was employed. The electrical measurements of the carbon-based devices were performed with a Keithley 2602 A source meter at ambient conditions.

After the mechanical data were obtained, the roughness of the fracture areas (R_a) of all AD, BDS, VV, WDD, C1, and C2 specimens was measured using a contact profilometer (Taylor Hobson Form TalySurf Serie 2 FTS S2, Leicester, UK). Since WNc and WNu both used the same resin, the fracture surface measurements were performed only on the WNc group, but the results may be considered to apply to both WN groups. The roughness parameter R_a stands for “roughness average”. It is the most common parameter for describing a surface’s roughness and is defined as the arithmetic mean of the absolute values of the roughness profile ordinates. The measurements were performed perpendicular to the surface. The profilometer filter settings were chosen according to the respective ISO norm [21 ]. Three standardised measurements of 4.0 mm were performed. The cut-off wavelength was set at λ = 0.8 mm, meaning that roughness peaks larger than 0.8 mm did not contribute to the result.
To gain a better understanding of the specific fracture surface configurations, scanning electron microscope (SEM) images were produced using a LEO-1550 FE-SEM (Carl Zeiss GmbH, Vienna, Austria) at magnifications of 100-fold and 450-fold.