Subsequently, for obtaining a smooth surface finish the 800 mesh grinding paper was applied.
The samples were embedded in Tra-Bond F113 epoxy, sectioned, and dry polished with silicon carbide grinding paper to minimize loss of water-soluble particles.
These features are interpreted to result from the rolling process of the as-received steel surface and, respectively, the two-step grinding process in case of the surface finally ground with the 800 mesh SiC grinding paper.
The abrasive wear resistance of the coatings was evaluated using pin-on-disk tests, during which a disk was covered by a 400 SiC grinding paper.
After grinding the polymer block to size with Buehler-met metallographic grinding paper, the surface was further dry-polished with a Polishing Cloth Texmet 1000 non-woven pad Buehler-Met GmbHH, Germany).
The first step included the removal of the topmost material layer with a thickness of 10 to 15 μm – as determined gravimetrically - using the grinding paper with a grit size of 320 mesh.
Additionally, the Ge STCS was ground down to an average nominal thickness of 100 µm using SiC grinding paper with successive grain sizes 2000 and 4000 on a grinding machine LaboPol-21 (Struers).
In the frame of a preliminary survey, steel surfaces with distinct roughness were investigated by OSEE after dry grinding of the SAE 1008/1010 steel substrates with distinct SiC grit-based grinding papers.
For the pretreatment of steel surfaces three kinds of grinding papers were used, in all cases waterproof silicon carbide papers with grit sizes of 80, 320 and 800 mesh, from Hermes Schleifmittel GmbH & Co. KG or from Struers GmbH respectively.
The obtained OSEE intensities are shown in Figure 3. Figure 3 Results of non-destructive surface analysis using Optically Stimulated Electron Emission (A) and photographic documentation (B) for grinding surfaces of SAE 1008/1010 steel substrates using grinding papers with SiC grit sizes of 80, 320, and 800 mesh and then exposing them in air for 1 min or 3 min.
After both the rolling and nitriding processes, cross-section of the samples were wet ground using SiC grinding papers and then polished for achievement of a mirror-like surface and afterwards etched by "10 ml HCL + 10 ml HNO3 + 10 ml acetic acid + 2 drops glycerol" etchant.
