Views: 7 Author: Site Editor Publish Time: 2017-11-14 Origin: Site
Pure tungsten and molybdenum products as sapphire growth furnace is an important material. Tungsten Molybdenum products for sapphire crystal furnace are mainly made of tungsten raw materials and molybdenum raw materials with purity over 99.95%, including tungsten crucible, tungsten plate, tungsten plate, tungsten wire, tungsten electrode screen, tungsten tube, tungsten barrier Hot screen, molybdenum crucible, molybdenum heat shield, molybdenum heating element, molybdenum hot field, molybdenum support frame and molybdenum electrode screen. In addition to tungsten and molybdenum products, tungsten rhenium wire is also a necessary product in a sapphire furnace.
Sapphire furnace tungsten products are gray gray to tin white hard metal, very pure tungsten can be sawed saw (pure tungsten is very brittle, not easy processing). Tungsten processing means forging, stretching and impact. Tungsten has the highest melting point of 3415 ° C in all metals, with the lowest vapor pressure and the highest tensile strength (1650 ° C). Corrosion resistance is very good, most of the inorganic acid erosion of small. The surface of the air forms a layer of protective oxide, but it is fully oxidized at high temperatures. Molybdenum products are also high temperature, high melting point refractory metal.
The sapphire growth furnace is designed to grow single-crystal sapphire by bubble-blowing. This method is achieved by heating the raw material (alumina) in the tungsten crucible to a temperature of 2050 ° C or above and then gradually lowering the melting temperature and crystallizing it into special particles. The growth furnace is constructed in a closed mold with a special insulated housing, lid and heater. Therefore, sapphire crystal furnace with tungsten and molybdenum products also appeared.
An important carrier of a crystal growth furnace is a tungsten-molybdenum crucible. Iridium crucible using the general iridium crucible itself is a heating element, but the use of tungsten, molybdenum crucible less used to do the crucible itself. Ikal-200 crystal growth furnace, the use of tungsten crucible, molybdenum crucible, molybdenum heat shield, tungsten Heating body, at high temperatures will volatilize molybdenum and tungsten atoms. Of course, the use of tungsten, molybdenum crucible itself is not a heating element is not, are relatively speaking, the choice of process and temperature field settings are very crucial factor. Different crystal growth methods, the use of the crucible will be different, such as the bubble generation method (KY) commonly used tungsten crucible, heat exchange method (HEM) commonly used molybdenum crucible, because the final heat exchange method to take a single crystal, and molybdenum crucible The cheapest price. According to the crucible manufacturing process, it can be divided into pressing and sintering crucibles and spinning crucibles. The pressing and sintering crucibles have lower quality, lower purity and lower density, relatively short service life and relatively low price. The spinning crucibles have higher quality, Higher, longer service life, high price. The domestic crystal growth furnace is usually pressed sintering crucible.
The chemical composition of the sapphire crystal is alumina (α-Al2O3), which is a combination of three oxygen atoms and two aluminum atoms covalently bonded to each other. The crystal structure of the sapphire crystal is a hexagonal lattice structure. In terms of color, pure alumina crystals are rendered clear and colorless due to the different color element ion penetration in the growth of sapphire, so sapphire show a different color. In nature, when sapphire is grown, the crystal contains titanium ions (Ti3 +) and iron ions (Fe3 +), causing the crystals to turn blue into sapphire. When the crystal contains chromium ions (Cr3 +), the crystals appear red ruby (Ruby). And when the crystal contains nickel ions (Ni3 +), the crystals will appear yellow to become a yellow stone. The crystal growth furnace used to grow sapphire is the key to the quality of the sapphire.
Tungsten molybdenum products are key carriers for sapphire crystal growth. The use of tungsten and molybdenum as a material, can well protect the purity of sapphire, tungsten and molybdenum because refractory metal is refractory, not easy to react with the sapphire.