A hem crystal growth method under the protection of inert gas

Abstract

The invention discloses a method for growing an HEM crystal under the protection of an inert gas. The method comprises the following steps:(1) putting the crystal in a crystal growing furnace; (2) sealing the inside of the crystal growing furnace and carrying out a vacuum treatment until the vacuum degree in the furnace reaches 5 to 10 millitorr; (3) slowly filling a HE (helium)-AR(argon) inert mixing gas with the volume ratio of HE to AR of being 1: (1.5 to 3) into the crystal growing furnace and removing impurities; and (4) heating the crystal growing furnace by using a heater and enabling the HEM crystal to grow, wherein the temperature in the furnace is always not lower than 2000 DEGC; and the HE-AR inert mixing gas is continuously filled during the crystal growing process until the crystal growth is finished. The method has the beneficial effect of realizing the HEM crystal growth by utilizing the HE-AR inert mixing gas, so that the crystal growing effect is good; and the problem of helium supply in the international requirement is avoided. In addition, the production cost is saved; and the procurement risk is reduced.

Description

technical field [0001] The invention relates to a HEM crystal growth method under the protection of an inert gas, belonging to the technical field of crystal production. Background technique [0002] There are several ways to grow sapphire crystals: pulling method, Kyropoulos method, HEM, inverted film method, etc. Among them, the HEM method has gradually become the main method for large-scale sapphire growth in recent years. Helium is filled in the sapphire crystal growth furnace as a protective gas and to take away the impurity gas removed from the crystal growth and thermal field. It is a consumable, and because helium is a natural resource in the universe, it is also non-renewable. Scarce strategic resources have important uses in satellite spacecraft launch, missile weapon industry, airship and other aerostats, low-temperature superconductivity research, semiconductor production, nuclear magnetic resonance imaging, special metal smelting, and gas leak detection. [00...

AI Technical Summary

Problems solved by technology

[0003] However, the distribution of helium reserves in the world is very uneven. North America, North Africa, Russia and other places have relatively rich helium resources, while my country's helium resources are seriously scarce, and only a small amount of helium is stored in Sichuan.

For a long time, my country's helium (including liquid helium) used in industrial production and scientific experiments has basically relied on foreign imports, so the price of domestic helium is relatively high, and the supply cycle of large quantities is very long

At the same time, with the development of my country's national defense industry technology, the demand for helium is increasing. Once a helium embargo occurs in an extraordinary period, the production cost and the risk of reducing procurement will be greater, which will definitely affect my country's national defense security on a large scale. and economic development