Table 2: Carbon content, density, and average grain size of the samples.
| Sample | Carbon content (wt%) | Relative density (%) | Average grain size (μm) | |
| Before sintering | After sintering | |||
| 440C | 1.20 | 0.94 | 97.8 | 90.3 |
| Nb440C | 0.95 | 0.91 | 98.5 | 48.3 |
| Nb440 + 0.15%C | 1.10 | 1.02 | 97.5 | 52.1 |
| Nb440 + 0.3%C | 1.25 | 1.15 | 97.5 | 59.1 |
| Nb440C + 0.45%C | 1.40 | 1.33 | 97.5 | 65.3 |