Advantages And Disadvantages Of Tungsten Crucible For Sapphire Growth

Apr 26, 2020

Tungsten and molybdenum products for sapphire long crystal furnace are mainly produced from tungsten raw materials with a purity higher than 99.95% and molybdenum raw materials, including tungsten crucible, tungsten plate, tungsten sheet, tungsten wire, tungsten electrode screen, tungsten tube, tungsten heat shield, molybdenum crucible, molybdenum heat shield, molybdenum heat heater, molybdenum heat field, molybdenum support frame and molybdenum electrode screen. Tungsten crucible is widely used in sapphire crystal growth due to its highest melting point of all metals.

The carrier of sapphire crystal growth furnace using tungsten crucible is seldom using tungsten crucible itself as heating body, and tungsten atoms will be volatilized at high temperature. It is also possible to use tungsten crucible itself as heating body, but the choice of process and the setting of working environment temperature are very critical factors. Due to the different preparation techniques of tungsten crucible, the pressing sintered tungsten crucible is generally used in the sapphire crystal growing furnace in China.

The advantage of tungsten crucible for sapphire single crystal growth lies in that the phenomenon of sticking to the pot often occurs in the de-crystallization stage of sapphire single crystal growth, but tungsten crucible is a refractory metal with high temperature resistance, which is not easy to react with sapphire, and can well protect the purity of sapphire. The sapphire single crystal made by the bubble method needs a good temperature field device, and the spinning tungsten crucible is of high quality, relatively high purity and density, but the price is also high.

The disadvantage of tungsten crucible for sapphire single crystal growth is that the tungsten crucible cannot be placed on the cold metal surface immediately after heating, otherwise it will break. Most tungsten crucible thickness is relatively thin, not conducive to long-term use, in the number of repeated use of poor performance, which will increase the cost of sapphire crystal growth.

Therefore, when choosing tungsten crucible for sapphire single crystal growth, the suitable type of tungsten crucible should be selected according to the preparation technology of single crystal and the conditions of single crystal growth furnace.