Alumina tubes have good thermal shock and good strength & chemical resistance. Alumina is compatible with platinum thermocouples for long term use in reducing or oxidizing atmospheres and should be used at temperature above 1200°C.

For Temperature Sensing

Alumina thermocouple protection tubes
Closed one end
Alumina insulators for thermocouples, thermistors
Single or Multi-bore tubing used to insulate wires


Composition 99.8% Al2O3
Bulk Density g/cm3 3.8
Flexural Strength MPa 345
Compressive Strength MPa 2650
Coeff of Thermal Exp (1000°C) 8x10-6
Thermal Conductivity (1200°C) W/m°K 8
Permeability Gas tight
Hardness GPa 14.0-15.0


  • Service temerature Up to 1870°C (3400°F) when properly supported
  • Fair resistance to thermal and mechanical shock
  • Superior resistance to reducing atmospheres
  • Induction melting, vacuum furnaces and glass manufacturing
  • Impervious to gases at high temperatures



  • Iron, barium, crown glass
  • non-ferrous metals
  • gas-tight protection for noble metal thermocouples in excess of 2400°F (1316°C)


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