Structural and tribological properties of nitrogen doped amorphous carbon thin films synthesized by CFUBM sputtering method for protective coatings

A comparison study between atomic and ionic nitrogen doped carbon films prepared by ion beam assisted cathode arc deposition at various pulse frequencies

“…Neuville [30] has reviewed that the conclusions on the material structure (various characterization results) should always be in agreement to each other and especially coherent with the hardness measurement. The hardness itself depends on chemical bonds [2,14,17,21,26,29] and atomic density within the films, especially when other types of atoms (contaminants, dopants such as O, N, B and metals) are incorporated in the carbon based films [31]. This interpretation can also support the phenomena that the hardness of CN x films increases in the case of cross-linking of graphitic planes by sp 3 bonded carbons, which is widely accepted in the literature [2,32].…”

“…This behavior is mainly due to the enhancement of implantation and re-sputtering of high energetic N ions in the carbon plasma. High energetic N ions lead to the partial defects related to the distortion of crosslinked sp 2 clusters into the C-networks and the increase of N Csp 2 content by thermal spike during the films growth (P3 in Table 3) [14,19]. (3) It seems that the concentration of oxygen in the CN x (N 2 ) and CN x (N + ) films (C3) increases with increasing the nitrogen content.…”

“…Especially for the latter, N bonded to two sp 2 C at the edge of a graphitic sheet (pyridine-like), N bonded to three sp 2 C in the center of a graphite sheet (graphite-like), pyrrolic-like or other heterocyclic nitrogen configurations, their N1s binding energy can vary in a broad range from 398.3 eV to 401.7 eV [19][20][21]. Table 2 roughly lists the assignment of main bonding configuration referred by different authors [2,14,16,17,[20][21][22][23][24][25][26][27][28][29]. Apparently it is difficult to assign the N bonding configuration if only compare them, because the investigated CN x films are distinctly different in the microstructure and synthesis conditions, but these factors can determine the bonding state of nitrogen atoms within the carbon matrix.…”

“…The deconvolution of the peaks was executed by curve fitting using Gaussian-Lorentz function, which the Gaussian fraction retains with 20% for all films. The C1s region consists of two well-resolved binding energy configurations, C1 at 284.5 ± 0.2 eV and C2 at 285.7 ± 0.2 eV, which are assigned to bonds with carbon (C C and C C) and carbon coordinated nitrogen bonds (C N and C N), respectively [14][15][16][17][18]. The third configuration located at about 287.7 ± 0.2 eV (denoted by C3) is attributed to carbon coordinated oxygen bonds (C O or C O) in the surface layer.…”

Synthesis and characterization of Ti and N binary‐doped ɑ‐C films deposited by pulse cathode arc with ionic source assistant

“…All spectra can be fitted to 3 peaks using Gaussian-Lorentz function with 20% Gaussian fraction. The low energy peak (C1) located at approximately 284.6 ± 0.2 eV and the second peak (C2) at 285.5 to 286 eV are assigned to carbon bonds in a pure C environment (C-C and C═C) and the carbon coordinated nitrogen bonds (C-N, C═N, or C ≡ N), respectively 26,[33][34][35]. The high energy peak (C3) at 287.4 to 288.5 eV is attributed to carbon coordinated oxygen bonds (C-O or C═O).…”