Table 1. Sample size of the subgroups in terms of the holding time and sintering temperature .
| Group TZI (n) | 30 min. | 60 min. | 120 min. | 240 min. | Total |
| 1400ºC | 10 | 10 | 10 | 10 | 40 |
| 1450ºC | 10 | 10 | 10 | 10 | 40 |
| 1500ºC | 10 | 10 | 10 | 10 | 40 |
| 1600ºC | 10 | 10 | 10 | 10 | 40 |
| Control Group | 10 | ||||
| Total | 170 | ||||
| Group UP (n) | 30 min. | 60 min. | 120 min. | 240 min. | Total |
| 1400ºC | 10 | 10 | 10 | 10 | 40 |
| 1450ºC | 10 | 10 | 10 | 10 | 40 |
| 1500ºC | 10 | 10 | 10 | 10 | 40 |
| 1600ºC | 10 | 10 | 10 | 10 | 40 |
| Control Group | 10 | ||||
| Total | 170 | ||||