Thermal Insulation

Growing crystals at high-temperature in a hot crucible requires low thermal conductivity materials for thermal insulation. It is important for being energy efficient and maintaining a consistently high temperature in the melting zone and protecting chamber components and assemblies against high temperatures.

By now, leuco sapphire manufacturers are able to grow large (up to 60 – 100 kg and larger) crystals at low cost. These results are achievable with our thermal insulation screens. For example, when growing large leuco sapphire boules with the Kyropoulos method it is necessary to be able to maintain a stable growth environment for seven or more days. Thermal insulation screens made of high refractory cubic zirconia concrete developed by RHT ensure the stability of super-high temperatures as well as significant energy saving. Cubic zirconia lining completely eliminates the need for molybdenum or wolfram screens.

Insulation