NIST Standard Reference Database 30
Last Update to Data Content: 2002
"Thermal Expansion of Reference Materials: Tungsten and α-Al2O3," G.K. White and R.B. Roberts, High Temperatures - High Pressures, Vol. 15, pp. 321-328 (1983), published by Pion Limited.Language: English
"The CODATA Task Group on Thermophysical Properties is preparting a set of recommended values for the thermal expansion... This paper deals with the expansion of... α-alumina from 10 K to 2000 K. Mean values are tabulated and new measurements are reported for alumina from 10 K to 300 K. ... There is no evidence that α is affected by trace impurities except at liquid helium temperature where magnetic ions may produce Schottky-type anomalies." The authors combined data from nine different studies to produce a set of recommended values.
"Alpha-alumina (corundum, sapphire) has axial symmetry and hence two principal coefficients of expansion, αc (parallel to the c-axis) and αab (perpendicular to the c-axis). At arbitrary angle ϑ, αϑ = αab (sin ϑ)2 + αc (cos ϑ)2 . The volume coefficient, β, is given by β = 2 αab + αc. The average linear coefficient, αav, is β/3 and equals αϑ when ϑ is about 55°. ... We have used this fact to adjust report α values from ϑ = 60°, 59°, ... to the 'average' at ϑ = 55°."
| Crystal Direction | Temperature ( K ) | Thermal Expansion ( 10-6 K-1 ) |
|---|---|---|
| c-axis | 20 | 0.006 |
| c-axis | 30 | 0.022 |
| c-axis | 40 | 0.054 |
| c-axis | 50 | 0.120 |
| c-axis | 60 | 0.22 |
| c-axis | 70 | 0.35 |
| c-axis | 80 | 0.52 |
| c-axis | 90 | 0.73 |
| c-axis | 100 | 0.98 |
| c-axis | 120 | 1.52 |
| c-axis | 140 | 2.14 |
| c-axis | 160 | 2.72 |
| c-axis | 180 | 3.30 |
| c-axis | 200 | 3.84 |
| c-axis | 250 | 5.01 |
| c-axis | 293 | 5.80 |
| c-axis | 300 | 5.90 |
| c-axis | 350 | 6.50 |
| c-axis | 400 | 7.08 |
| c-axis | 450 | 7.57 |
| c-axis | 500 | 7.94 |
| c-axis | 550 | 8.30 |
| c-axis | 600 | 8.55 |
| c-axis | 650 | 8.79 |
| c-axis | 700 | 8.97 |
| c-axis | 800 | 9.29 |
| c-axis | 900 | 9.54 |
| c-axis | 1000 | 9.70 |
| ab-plane | 20 | 0.003 |
| ab-plane | 30 | 0.013 |
| ab-plane | 40 | 0.039 |
| ab-plane | 50 | 0.08 |
| ab-plane | 60 | 0.16 |
| ab-plane | 70 | 0.26 |
| ab-plane | 80 | 0.40 |
| ab-plane | 90 | 0.57 |
| ab-plane | 100 | 0.73 |
| ab-plane | 120 | 1.15 |
| ab-plane | 140 | 1.64 |
| ab-plane | 160 | 2.15 |
| ab-plane | 180 | 2.70 |
| ab-plane | 200 | 3.21 |
| ab-plane | 250 | 4.27 |
| ab-plane | 293 | 5.06 |
| ab-plane | 300 | 5.15 |
| ab-plane | 350 | 5.77 |
| ab-plane | 400 | 6.36 |
| ab-plane | 450 | 6.81 |
| ab-plane | 500 | 7.19 |
| ab-plane | 550 | 7.50 |
| ab-plane | 600 | 7.72 |
| ab-plane | 650 | 7.93 |
| ab-plane | 700 | 8.10 |
| ab-plane | 800 | 8.36 |
| ab-plane | 900 | 8.65 |
| ab-plane | 1000 | 8.83 |
| mean | 20 | 0.004 |
| mean | 30 | 0.016 |
| mean | 40 | 0.044 |
| mean | 50 | 0.095 |
| mean | 60 | 0.18 |
| mean | 70 | 0.29 |
| mean | 80 | 0.44 |
| mean | 90 | 0.61 |
| mean | 100 | 0.81 |
| mean | 120 | 1.28 |
| mean | 140 | 1.80 |
| mean | 160 | 2.34 |
| mean | 180 | 2.90 |
| mean | 200 | 3.42 |
| mean | 250 | 4.52 |
| mean | 293 | 5.30 |
| mean | 300 | 5.40 |
| mean | 350 | 6.08 |
| mean | 400 | 6.64 |
| mean | 450 | 7.10 |
| mean | 500 | 7.46 |
| mean | 550 | 7.75 |
| mean | 600 | 7.99 |
| mean | 650 | 8.18 |
| mean | 700 | 8.35 |
| mean | 800 | 8.62 |
| mean | 900 | 8.86 |
| mean | 1000 | 9.09 |
| mean | 1100 | 9.34 |
| mean | 1200 | 9.59 |
| mean | 1300 | 9.85 |
| mean | 1400 | 10.09 |
| mean | 1500 | 10.31 |
| mean | 1600 | 10.51 |
| mean | 1700 | 10.67 |
| mean | 1800 | 10.84 |
| mean | 1900 | 11.05 |
| mean | 2000 | 11.37 |
Cumulative expansion from 293 K. α(T) = [1/L(293)] [L(T) - L(293)]/[T - 293]