SS Scientific offer two types of filament coating, Thoria or Yttria.
Filaments can be coated as part of our filament manufacturing process or as a service for coating filaments that our customers supply.
Iridium typically requires an emission coating to perform as well as Tungsten.
The most common coating is Thorium Oxide (Thoria) or Yttrium Oxide (Yttria) as a non radioactive coating.
Thoria coated Iridium filaments provide a longer life and less sensitivity to oxygen exposure.
Yttria is a good replacement for Thoria and eliminates the environmental problems associated with Thoria.
Yttria coated filaments require less power than filaments without coating and the filament operates at a lower temperature to achieve the same emission.