Method for growing crystal by reducing atmosphere Kyropoulos method

Abstract

The invention relates to a method for growing crystal by reducing atmosphere Kyropoulos method; the method is characterized in that on the basis of growing crystal by induction heating pulling method, a tungsten, or molybdenum, or tungsten molybdenum alloy crucible is used; graphite felt which is arranged outside the crucible is used as a heat insulator; the reducing atmosphere is formed at high temperature; a hard graphite felt heat cover or a zirconia brick heat cover combined with a tungsten molybdenum after heater are placed above the crucible to preserve heat for fused mass in the crucible and the crystal grows; an observation window is arranged at the upper cover of the heat cover and the upper side of a furnace wall to ensure uniformity and symmetry of temperature field and temperature gradient distribution; the observation window arranged at the upper cover of the heat cover and the upper side of the furnace wall are used to observe the fused mass and the conventional pulling method is used to carry out parallel shouldering on inoculating crystal; then power is reduced at a certain speed, meanwhile, the crystal can be slightly pulled or not pulled, that is the Kyropoulos method; after crystallization is over, power is continued to be reduced to lower the temperature of the crystal. With the method of the invention adopted, large-size and high-quality crystal can be grown at low cost.

Description

technical field [0001] The invention relates to a crystal growth method, in particular to a method for growing crystals by a reducing atmosphere kerosene method, which can obtain large-sized and high-quality crystals. Background technique [0002] Growing large-size, high-quality crystals at a lower cost is the relentless goal pursued by scientists and technicians engaged in crystal growth. There are many methods of crystal growth, but the most commonly used and most important is to grow crystals from the melt, which mainly includes the pulling method, the temperature gradient method and the Kyropoulos method. [0003] Among them, the pulling method is the most commonly used method for growing high-quality single crystals from the melt. This method can grow important gemstones such as sapphire, ruby, yttrium aluminum garnet, gadolinium gallium garnet and spinel. crystals. However, the growth of compound crystals by the pulling method usually requires expensive platinum, ir...

AI Technical Summary

Problems solved by technology

Invention 200710073268.8 (application number) is based on the patent ZL200310112171.5 and relates to "a lithium aluminate crystal growth method". In addition to the defects of the patent ZL200310112171.5, the invention has an observation window on the side wall of the heat preservation cover. The observation window will lead to asymmetry of the temperature field and temperature gradient distribution, causing strong gas convection between the inner cavity of the insulation cover above the melt and the outside of the cover. A large number of experimental results have proved that the above observation window is the cause of lithium aluminate crystal growth. The fundamental reason for the volatilization of serious components, so it is difficult to obtain high-quality lithium aluminate crystals using this kind of heat preservation cover

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