The vapor pressure of MgF 2 is high, and the raw material is volatile in the open system grown by czechoski method. Therefore, the growth process of MgF 2 crystal needs to be carried out under positive pressure. First, the crystal growth furnace is vacuumized to vacuum, and then filled with high purity argon to slightly positive pressure. After the gas is uniform, the argon gas is extracted to remove impurities in the furnace, such as water and oxygen. The process is repeated until the vacuum state in the crystal furnace is reached and the temperature is raised to the melting point of the magnesium fluoride sintered material. Application analysis of MgF 2 crystal materials a certain amount of deoxidizer is added in the growth process of MgF 2 crystal to prevent oxygen or hydroxyl from entering the crystal. The processed crystal material is filled into graphite. Among the known materials up to now, magnesium fluoride crystal is one of the materials with good light transmission performance in the vacuum ultraviolet band. Magnesium fluoride crystals range from VUV to red. The single crystal atoms are arranged in a uniform and long-distance order, showing the preferred orientation. Because there are no grain boundaries, adjacent particles (or fluorides). From the domestic and international market and production process, the competitive market is the dry aluminum fluoride production process and its products.
Among the known materials up to now, magnesium fluoride crystal is one of the materials with good light transmission performance in the vacuum ultraviolet band. Magnesium fluoride crystal has good permeability from VUV to IR, and is a common window material for IR and UV detectors. With the rapid development of high-power laser technology, high-precision imaging technology, infrared guidance technology and semiconductor lithography technology, the market demand for magnesium fluoride is increasing rapidly, especially in the foreseeable time. The state of being in short supply.
Compared with the polycrystalline magnesium fluoride, the single crystal has higher transmittance in the ultraviolet region. In addition, the physical properties of single crystal materials are better than that of polycrystalline materials, which have the advantages of high mechanical strength, thermal shock resistance and not easy to crack along the grain boundary.
Magnesium fluoride is easily oxidized or hydrolyzed at high temperature to produce magnesium oxide impurities. Magnesium oxide has high melting point and is not easy to volatilize. MgO remaining in the growth system will reduce crystal filtration and lead to defects such as scattering particles inside the crystal. Therefore, oxygen and water vapor must be avoided in the whole process of crystal growth. It is necessary to add a certain mass percentage of deoxidizer to magnesium fluoride raw material, which can not only effectively remove the water in raw material and crystallization furnace, but also further fluorinate the raw material to avoid hydrolysis or oxidation. Magnesium fluoride crystal material.
The vapor pressure of MgF 2 is high, and the raw material is volatile in the open system grown by czechoski method. Therefore, the growth process of MgF 2 crystal needs to be carried out under positive pressure. First, the crystal growth furnace is vacuumized to vacuum, and then filled with high purity argon to slightly positive pressure. After the gas is uniform, the argon gas is extracted to remove impurities in the furnace, such as water and oxygen. The process is repeated until the vacuum state in the crystal furnace is reached and the temperature is raised to the melting point of the magnesium fluoride sintered material.