A Method For Extracting Sapphire Ingots From Tungsten Crucible

Oct 25, 2019

Tungsten crucible is the core component of sapphire single crystal growth furnace, which is widely used in the growth crystal industry of sapphire. The waist of the tungsten crucible will be deformed when it works at high temperature for a long time, because the sapphire crystal ingots in the tungsten crucible are in a "pear-shaped" state, small at the top and large at the bottom. When the waist of the crucible is deformed to a certain extent, the sapphire ingots can easily get stuck in the deformed part of the tungsten crucible and cannot be safely removed. In addition, the tungsten crucible and crystal sapphire ingot are very high hardness and has bigger brittleness material, very prone to brittle crack when squeezed, therefore, are stuck in the extraction of tungsten crucible sapphire ingot by hydrogen peroxide preheating, hydrogen peroxide solution immerse inside crucible, take tungsten crucible was stuck inside ingot, tungsten crucible subsequent processing these four steps.

Firstly, preheat hydrogen peroxide, pour industrial pure hydrogen peroxide or analytical pure hydrogen peroxide into the beaker, and place it on the electric furnace for heating, heating to 50-70℃. The tungsten crucible is then continuously filled with heated hydrogen peroxide, soaking the ingots in hydrogen peroxide where they are stuck. After standing for 6-8 hours, if the hydrogen peroxide is yellowish green in color and no bubbles appear on the surface of the liquid, the solution can be poured out and then repeated into the tungsten crucible with hydrogen peroxide for 3-4 times. After the pouring, the stuck ingot in the crucible was bound with copper braided belt, and the stuck ingot was removed with the help of moving the stack car and lifting chain. Take out the card crystal ingots to use the method of processing on the inner wall of the tungsten crucible processing, in order to improve the deformation of the tungsten crucible position, in case the ingots were stuck again.

In addition to the above methods, the most commonly used extraction method is mechanical grinding. The deformed part of the tungsten crucible is manually ground with an alloy or ceramic cutter to enlarge the inner diameter of the waist of the tungsten crucible and finally to remove the stuck crystal ingots. However, because this method is manual control, it needs more time and energy. If the tungsten crucible is struck to remove the stuck crystal ingots, it will cause a lot of waste.