XPS spectra of CC620 at 250 m/min are presented in Figure 11. An adequate amount of alumina(Al2O3) tribo-film with sapphire crystal structure was found (HR Al2s spectrum, binding energyof 117 eV). This tribo-film acts as a thermal barrier at elevated cutting temperatures prevents heat penetration to the tool surface and subsurface that can cause the tool damage; moreover, this tribo-film formation reduces the adhesive wear effect [20]. ZrO2 tribo-film was detected in Figure 11 (HR Zr3d spectrum, binding energy of 183.3 eV). Its formation decreases the coefficient of friction at the tool-chip interface [37]. The detection of these tribo-films supported the results obtained from the wear curve at 250 m/min in Figure 3, chip compression ratio presented in Figure 9, and the chip underside micrographs illustrated in Figure 11. When the cutting speed reaches 700 m/min, ZrO2 tribo-film becomes ineffective due to the expected increase of the cutting temperature to more than 900 ◦C.This was shown by the wear curve in Figure 5.