Alumina disc, OD82mm*T6mm, Item# AL-D-82-6

Description

Alumina disc, OD82mm*T6mm, Item# AL-D-82-6
Alumina (Al2O3) has a wide application due to its versatility and low material cost. Alumina possesses a high melting point, strong hardness, and good chemical stability, making it a good material to withstand high temperature and chemical corrosion.
The recommended maximum service temperature for alumina crucibles is 1750 Celsius Degree.  Alumina crucible is sensitive to thermal shock.  So it is important to keep slow temperature change rate and even heating during the process.  Some general usage guidelines are as below:
Alumina products are fragile. Please handle them carefully and avoid collision during unpacking, transportation, handling and cleaning.
Check whether any micro-cracks exist before using alumina products. Products with micro-cracks should not be used.
Alumina products should be completely dry before usage. If they get wet, let the crucible or tube dry naturally before using them. If dry crucibles by placing in a dryer or oven, make sure that the dry process goes slowly.
Do not load too many materials in alumina crucibles, which can increase the possibility of uneven heating.
Alumina crucibles are sensitive to thermal shock. Try to warm up the furnace chamber slowly. A heating rate of 150°C/hour is recommended for the first 1-1.5 hours so that the crucibles can be evenly heated to reduce the impact of thermal shock. It usually takes about 3 hours to increase to high temperature.  A 3°C/minute temperature change rate is recommended.
Lower the temperature as gradually as possible. The cooling down rate is often half of the heating rate. If possible, arrange for consecutive heating of furnace to maintain a hot crucible. If taking the crucibles out of furnace into room temperature to pour the melted material, try to control the process as short as possible.
Avoid contact of heated alumina products with a cold surface. Use insulation materials as support of alumina crucibles.
Alumina crucibles should not be heated by torch or furnaces that cannot control temperature change rate. The uneven heating can cause crack.