| Nitrogen flow rate (sccm) | Chemical compositions (at.%) | |||
| C | N | Cr | O | |
| 0 | 95.4 | 0 | 3.3 | 1.3 |
| 20 | 90.0 | 6.1 | 2.2 | 1.7 |
| 40 | 84.5 | 10.2 | 3.4 | 1.9 |
| 60 | 84.0 | 10.0 | 3.6 | 2.4 |