NIST Standard Reference Database 30
Last Update to Data Content: 2002
"Microhardness of a Fine-Grain-Size Al2O3," S.D. Skrovanek and R.C. Bradt, Journal of the American Ceramic Society, Vol. 62 [3], pp. 215-216 (1979), published by American Ceramic Society.Language: English
"Commercial α-Al2O3 with 0.5% MgO, hot pressed at 1600 °C, was used. ... Specimens (about 1 cm cubes) were annealed at 1200 °C to 1800 °C, yielding a range of grain sizes which were measured by the linear intercept technique on fracture surfaces observed in an SEM."
"Microhardness was measured on diamond-polished surfaces, using a 400 g load on a Knoop indenter with a commercial microhardness tester. The load was applied automatically over a 15 s interval and allowed to remain on the sample for an additional 30 s. The 50 µm indentation traversed several grains and grain boundaries. Indentations were repeated until 20 distinct, symmetrical, uncracked indentations were achieved. Averages were calculated..."
| Annealing Temperature ( °C ) | Grain Size ( µm ) | Hardness ( GPa ) |
|---|---|---|
| --- | 1.9 | 19.7 |
| 1200 | 2.3 | 19.6 |
| 1200 | 2.1 | 19.5 |
| 1200 | 2.0 | 19.4 |
| 1300 | 2.3 | 19.4 |
| 1300 | 2.0 | 19.5 |
| 1300 | 1.9 | 19.5 |
| 1400 | 2.3 | 19.5 |
| 1400 | 2.1 | 19.4 |
| 1400 | 2.0 | 18.9 |
| 1500 | 2.3 | 19.4 |
| 1500 | 2.1 | 19.4 |
| 1600 | 5.6 | 18.1 |
| 1600 | 4.9 | 18.4 |
| 1600 | 4.5 | 18.6 |
| 1600 | 4.3 | 19.0 |
| 1600 | 4.0 | 19.1 |
| 1700 | 7.3 | 17.6 |
| 1700 | 6.5 | 17.9 |
| 1700 | 5.4 | 18.6 |
| 1750 | 6.1 | 17.5 |
| 1750 | 5.1 | 17.7 |
| 1800 | 8.4 | 16.2 |
| 1800 | 5.5 | 16.5 |
Data were digitized from Fig. 2 of the reference.