Spinel MgAl2O3
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Transmission Range
0.3 to 5 μm
Refractive Index
1.71 at 0.6 μm
Reflection Loss
13% at 0.6 μm (2 surfaces)
Absorption Coefficient
0.02 cm-1 @ 0.6μm
Reststrahlen Peak
n/a
dn/dT
12 x 10-6 K-1
dn/dμ = 0
n/a
Density
4.58 g/cc
Melting Point
2135°C
Thermal Conductivity
14.6 W m-1 K-1 (varies with porosity)
Thermal Expansion
6.5 x 10-6 K-1
Hardness
Knoop 1140 with 1000g indenter (8 Moh)
Specific Heat Capacity
1086 J Kg-1 K-1
Dielectric Constant
8
Youngs Modulus (E)
195 GPa
Shear Modulus (G)
157 GPa
Bulk Modulus (K)
200 GPa
Elastic Coefficients
C11 = 298 C12 = 154 C44 = 157 (2)
Apparent Elastic Limit
170 MPa (24,600psi)
Poisson Ratio
0.26
Solubility
Insoluble in water
Molecular Weight
142.27
Class/Structure
Cubic Fd3m (#227) Irregular cleavage on (111)
| µm | No |
|---|---|
| 0.36 | 1.7461 |
| 0.4 | 1.7638 |
| 0.5 | 1.7229 |
| 0.6 | 1.7156 |
| 0.7 | 1.7111 |
| 1.042 | 1.702 |
| 1.25 | 1.698 |
| µm | No |
|---|---|
| 1.471 | 1.695 |
| 2.00 | 1.686 |
| 2.50 | 1.677 |
| 3.125 | 1.662 |
| 3.704 | 1.645 |
| 4.00 | 1.635 |
| 5.00 | 1.594 |
| µm | No |
|---|---|
| 5.556 | 1,565 |
| 6.25 | 1.522 |
| 6.667 | 1.491 |
| 6.897 | 1.473 |
Spinel is a naturally occurring material often used as a gemstone. Optical spinel is a fused compacted ceramic material formed from spinel powder. It is polycrystalline with a grain size in the range of 25μm to 150μm
1. https://www.mindat.org/min-3729.html
2.Schrieber. Elastic Modulii of Single Crystal Spinel. J App. Phys 38, 2508 (1967)