NIST Standard Reference Database 30
Last Update to Data Content: 2002
"Strength Characterization of Yttria/Alumina-Doped Sintered Silicon Nitride," R.K. Govila, International Journal of High Technology Ceramics, Vol. 3, pp. 179-197 (1987), published by Elsevier Applied Science.Language: English
"This study was undertaken to characterize the strength of an in-house (Ford Scientific Laboratory) developed yttria/alumina-doped sintered silicon nitride (Ford material-RM 20)... This material... is a sintered silicon nitride and contained 8 % yttria and 2 % alumina (mass fractions) as the major sintering additives."
"Flexural test specimens ( about 32 mm long by 6 mm wide by 3 mm thick) were machined from two billets, namely, A42 and A40. All faces were ground lengthwise using 320 grit diamond wheels; the edges were chamfered (lengthwise) to prevent notch effects. For flexural strength evaluation, specimens were tested in 1/4-point, 4-bending (inner span is one-half of outer span) in an Instron testing machine (model 1125) using specially designed self-aligning ceramic fixtures made from hot-pressed SiC. The outer and inner knife edges of the testing fixture were spaced 19 mm and 9.5 mm apart, respectively. The high temperature bend tests were conducted in air using a rapid temperature-response furnace attached to the testing machine head. In high temperature tests, specimens were held at the test temperature for 15 min to achieve equilibrium before testing was begun. No preload was applied on test specimens for either room temperature or high temperature tests. All specimens were tested at a machine crosshead speed of 0.5 mm/min."
| Amount of Element ( formula units ) |
Element ( no unit ) |
|---|---|
| 3 | Si |
| 4 | N |
| Mass Fraction ( % ) |
Sintering Aid ( no unit ) |
|---|---|
| 8 | Y2O3 |
| 2 | Al2O3 |
| Temperature ( °C ) |
Sample Number |
Flexural Strength ( MPa ) |
|---|---|---|
| 20 | A42 | 873 ± 79 |
| 400 | A42 | 872 ± 71 |
| 600 | A42 | 772 ± 22 |
| 800 | A42 | 700 ± 18 |
| 1000 | A42 | 637 ± 40 |
| 1200 | A42 | 563 ± 58 |
| 1300 | A42 | 316 ± 12 |
| 1400 | A42 | 327 ± 200 |
| 20 | A40 | 777 ± 59 |
| 400 | A40 | 792 |
| 500 | A40 | 771 ± 178 |
| 600 | A40 | 781 ± 96 |
| 800 | A40 | 726 ± 69 |
| 1000 | A40 | 679 ± 64 |
| 1200 | A40 | 530 ± 17 |
"(The) two billets, A42 and A40, ... were of identical composition but processed at different times."
| Temperature ( °C ) |
Sample Number |
Weibull Modulus ( no unit ) |
|---|---|---|
| 20 | A42 | 13 |
| 20 | A40 | 16 |
| Temperature ( °C ) |
Sample Number |
Weibull Strength ( MPa ) |
|---|---|---|
| 20 | A42 | 899 |
| 20 | A40 | 800 |