Polycrystalline Tubes and Rods

Translucent Tubes and Rods Offer Sapphire-Like Properties at a Lower Cost

CoorsTek polycrystalline tubes and rods are crafted from 99.9% aluminaSintered at very high temperatures (~1850°C) under reducing conditions, CoorsTek high-purity translucent alumina offers properties nearly identical to sapphire at a considerably lower cost.

Benefits of translucent alumina include:

  • Translucent and non-porous, meeting specifications of 100% sapphire tubes and rods at a fraction of the cost
  • Temperature resistance up to 1800 °C
  • Chemically inert, corrosion, and scratch resistant
  • High-volume production and thorough testing systems ensure the highest quality at the best value
  • High purity (99.9% Al2O3)
  • Outstanding dielectric loss (tan delta)

Translucent tubes and rods made with technical ceramics.

All polycrystalline tubes and rods are sized to customer specifications and are available in the following dimensions:

  • ∅1.0 to ∅18.5mm
  • Up to 990 mm length for dense products
  • Up to 1200 mm length for porous and non-porous tubes
Polycrystalline Alumina Tube

polycrystalline alumina protection tubes

Utilizing core extrusion and ceramic injection molding technologies developed over decades, CoorsTek manufactures high-quality alumina protection tubes. Using a special drying process after extrusion enables us to produce tubes and rods with the highest accuracy in radial dimensions. By combining high purity alumina with an innovative sintering method it is possible to create highly dense, pore free products with sapphire like properties at a fraction of the cost.



Polycrystalline sapphire-like caps are applicable in aggressive environments and/or at high temperatures where standard ceramics or metal tubes do not meet material sustainability requirements. Application areas include:

  • Chemistry labs
  • Glass
  • Oil refineries
  • Other laboratories


CoorsTek polycrystalline sapphire-like caps are competitive with other sapphire tubes and are a reliable substitution for ceramic tubes that are not resistant against chemical diffusion, offering much higher durability for thermocouple protection. Even small diameter tubes are strong and highly temperature resistant. 

Sets can consist of an outer one-sided sealed protective tube and one or more inner capillaries used for electrical insulation of branches of the thermocouple.