Growing Furnaces Thermal Protection Screens

Our company offers thermal protection ceramic screens made of cubic zurconia concrete for large leuco sapphire boule growing furnaces using the Kyropoulus, Czochralski, HDM and other hot crucible processes.

Insulation screens

The advantages compared to traditional screens made of molybdenum and wolfram are:
  • electrical energy saving – up to 50% (because of low thermal
  • conductivity – λ= 1-2 W/m3);
  • durability – term of service is up to 3 years and longer (molybdenum screen needs to be changed every half year);
  • high heat resistance;
  • stability of geometric dimensions (no shrinkage);
  • working temperature of up to 2500 oС;
  • the option of increasing the useful volume of furnace working space;
  • no interaction with wolfram and molybdenum parts of furnaces;
  • no evaporation of unwanted impurities;
  • easy to install and remove.
Due to all these properties, the demand for cubic zirconia screens manufactured by RHT is rapidly growing. According to references, employing our heat protection technology not only allows for temperature stabilization with larger mono-crystals, but also lowers the cost of manufacturing per kilo of leuco sapphire by 20 to 25%.

The screen is made of stabilized cubic zirconia grains with 80-82% of zirconium dioxide content and 18-20% of yttrium oxide dopant. Barium mono-aluminate (BaAl2O4) is used as a highly refractory cement.

To ensure thermal resistance, the article is assembled from separate segments and manufactured by special order to fit the particular size of the growing furnace crucible.

Insulation screens
Insulation screens