Surmet is a leading supplier of optical products made from Spinel, a high performance, transparent and polycrystalline ceramic material

Surmet’s Magnesium Aluminate Spinel, or simply Spinel, is a durable polycrystalline ceramic with optical transparency from the near ultraviolet through the mid-wave infrared (MWIR) spectrum. Surmet produces Spinel blanks and finished optics using its own proprietary processes. The result is an exceptionally strong optical ceramic ideal for high-performance, precision optical components.


Surmet’s Spinel Optical Ceramic

  • Optically transparent from near-ultraviolet through mid-wave infrared frequencies
  • Available in a wide variety of shapes, sizes and thicknesses
  • Fabricated using proven ceramic processing techniques
  • Ideal material for precision optical components

Comparison of Transmission

Spinel transmits out further into the MWIR than Sapphire, which in turn transmits further than ALON® Optical Ceramic.


Spinel Optical Ceramic Properties

Grain Size (typical):
Bimodal, 25 μm average and 150 μm average
Cubic, Spinel
Lattice Constant:
8.082 A
3.58 g/cc
Melting Point:
Young's Modulus:
276 GPa
Shear Modulus:
18.9x106 psi
Poisson's Ratio:
1650 Kg/mm2 (Knoop Indent, 200g)
Fracture Toughness:
1.5 MPa-m1/2
Flexure Strength:
170 MPa
Specific Heat:
0.8191 J/g -°C
Transmission Limits:
0.25 to 6.5 microns
Thermal Conductivity:
25 W/m-C @ 25°C