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Spinel

Spinel

We offer precision spinel spheres starting 0.20 mm. Due to its monocubic structure, spinel has almost no refringence. It supports high temperature and has a good shock resistance. Spinel is a very interesting material for optical applications.  

Physical properties crystalline structure Cubic monocrystal
  composition MgO · 3.5 Al2O3
  purity 99,99 %
  density 3.61
  dislocation density 109 – 108 /m2
     
Thermal properties melting point 2300-2330 K
  softening point 2070 K
  specific heat 7.9 · 102 j/kg ·K at 300 K
  thermal expansion 5.9 · 10-6 /K
     
Mechanical properties hardness Mohs 8
    Knoop 1175-1380
  young’s modulus 4.4 · 1011 Pa at 300 K
  modulus of rupture 4.0 · 108  Pa at 300 K
  compressive strenght 2.1 · 109  Pa at 300 K
  tensile strength 1.9 · 108  Pa at 300 K
  poisson’s constant 0.30
     
Chemical properties acids and alkalis attack 0 at ambiant temperature
  porosity 0
     
Electrical properties dielectric constant  8-9
     
Optical properties refractive index Nd at 0.5893 µm 1.727
  chromatic dispersion (nf – nc) 0.012
  Transmission, disc thickness 1 mm :  
  - infrared 85% 1µm