# Influence of Carbon: Metal Ratio on Tribological Behavior of Mo-W-C Coating
## 3 Results
### Friction Behavior during lubricated Sliding
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Coating Properties**} & **Mo-W-C Coatings** & **C2** & **C4** & **C6** \\ \cline{2-5}  & **C/(Mo+W) Ratio** & **5:1** & **2.8:1** & **2.2:1** \\ \hline \multirow{7}{*}{Microstructural properties} & Coating thickness (\(\mu\)m) & \(\sim\)1.89 & \(\sim\)2.24 & \(\sim\)2.79 \\ \cline{2-5}  & Critical load L\({}_{\text{c3}}\) (N) & 34.6 & 80.8 & 85 \\ \cline{2-5}  & Average nano-hardness (HV) & 1335.8 & 1677.5 & 1702.4 \\ \cline{2-5}  & Average elastic modulus (GPa) & 194.5 & 236.2 & 268.5 \\ \cline{2-5}  & \(H/E\) ratio & 0.067 & 0.07 & 0.062 \\ \cline{2-5}  & D peak position (cm\({}^{-1}\)) & 1119.6 (D1), 1393.05 (D2) & 1387.04 & 1406.7 \\ \cline{2-5}  & G peak position (cm\({}^{-1}\)) & 1576.52 & 1574.32 & 1579.37 \\ \cline{2-5}  & \(I_{D}/I_{\text{C}}\) ratio & 2.51 & 1.96 & 1.85 \\ \hline \multirow{7}{*}{Tribological properties} & Mean \(\mu\) & \(\sim\)0.047 & \(\sim\)0.033 & \(\sim\)0.052 \\ \cline{2-5}  & D peak position (cm\({}^{-1}\)) & 1385.84 & 1390.85 & 1398.12 \\ \cline{2-5}  & G peak position (cm\({}^{-1}\)) & 1572.06 & 1572.61 & 1582.44 \\ \cline{2-5}  & \(I_{D}/I_{\text{C}}\) ratio & 2.69 & 2.72 & 2.46 \\ \cline{2-5}  & Wear coefficient Kc & & & \\ (m\({}^{3}\)N\({}^{-1}\)m\({}^{-1}\)) of coating & & & & \\ \cline{2-5}  & Wear coefficient Kc & & & \\ (m\({}^{3}\)N\({}^{-1}\)m\({}^{-1}\)) of counterpart & & & & \\ \hline \multirow{7}{*}{Tribological properties at ambient temperature} & Mean \(\mu\) (run-in period) & \(\sim\)0.074 & \(\sim\)0.095 & \(\sim\)0.087 \\ \cline{2-5}  & Mean \(\mu\) (steady-state period) & \(\sim\)0.036 & \(\sim\)0.065 & \(\sim\)0.061 \\ \cline{2-5}  & Mean \(\mu\) (overall) & \(\sim\)0.042 & \(\sim\)0.072 & \(\sim\)0.07 \\ \cline{2-5}  & MoS\({}_{2}\) peak position (cm\({}^{-1}\)) & 382.5 (position ’a’), 402 (position ’b’) & 379, 408 & \multirow{2}{*}{381 (position ’b’)} \\ \cline{2-5}  & MS\({}_{2}\) peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & of tribolayer on counterpart & 412 (position ’b’) & 323 (position ’a’), 406.5 (position ’b’) & 319 (position ’a’), 408 (position ’b’) \\ \cline{2-5}  & D peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & of tribolayer on counterpart & 1361.33 & 1349.53 (D1), 1479.81 (D2) & 1368.27 \\ \cline{2-5}  & G peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & of tribolayer on counterpart & 1591.06 & 1580.27 & 1582.03 \\ \cline{2-5}  & \(I_{D}/I_{\text{C}}\) ratio of tribolayer on counterpart & 2.14 & 1.41 & 1.3 \\ \cline{2-5}  & MoS\({}_{2}\) peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & of tribolayer within wear track & - & & \\ \cline{2-5}  & WS\({}_{2}\) peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & of tribolayer within wear track & - & & \\ \cline{2-5}  & D peak position (cm\({}^{-1}\)) & 1141.05 (D1), 1389.33 & 1372.35 \\ \cline{2-5}  & G peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & G peak position (cm\({}^{-1}\)) & & & \\ \cline{2-5}  & of coating within wear track & 1588.52 & 1575.87 & 1588.56 \\ \cline{2-5}  & \(I_{D}/I_{\text{C}}\) ratio of coating within wear track & 1.36 & 1.55 & 1.49 \\ \hline \multirow{2}{*}{Tribological properties at 200 \({}^{\circ}\)C} & Wear coefficient Kc & \(\sim\)0.92 \(\times\) 10\({}^{-15}\) & \(\sim\)1.11 \(\times\) 10\({}^{-15}\) & \(\sim\)1.02 \(\times\) 10\({}^{-15}\) \\ \cline{2-5}  & (m\({}^{3}\)N\({}^{-1}\)m\({}^{-1}\)) of coating & & & \\ \cline{2-5}  & Wear coefficient Kc & \(\sim\)10.8 \(\times\) 10\({}^{-13}\) & \(\sim\)3.44 \(\times\) 10\({}^{-13}\) & \(\sim\)6.17 \(\times\) 10\({}^{-13}\) \\ \cline{2-5}  & Wear coefficient Kc & \(\sim\)0.92 \(\times\) 10\({}^{-15}\) & \(\sim\)1.