Growth process of magnesium silicate crystal with doped quadrivalent chromium

Abstract

The growing method of magnesium metasilicate crystal adopts radio-frquency induction heating pulling process and utilizes medium-frequency induction heating pulling furnace whose furnace body is equipped with nitrogen gas inlet valve, oxygen gas inlet valve and gas outlet valve, and includes the following steps: coating external surface of iridium crucible with a protective layer prepared with mixed powder of iridium powder and zirconium oxide powder: charging nitrogen gas into furnace body and retaining flowing state in the processes of heating, seeding down, necking-down and shouldering; before the isometric growth is started, opening oxygen gas inlet valve, mixing oxygen gas and nitrogen gas according to a certain ratio and feeding the mixed gas into furnace body, and retaining flowingstate, after the isometric growth is completed, closing oxygen inlet valve, after end work is completed, cooling to room temp. under the vacuum condition.

Description

Technical field: [0001] The invention relates to a growth method of tetravalent chromium-doped magnesium silicate crystals, in particular to a method for growing tetravalent chromium-doped magnesium silicate crystals to protect an iridium crucible, and has good application prospects in the field of crystal growth. Background technique: [0002] Magnesium silicate doped with tetravalent chromium (Cr 4+ : Mg 2 SiO 4 ) crystals must be grown under an oxidizing atmosphere, but under an oxidizing atmosphere, the iridium crucible is severely oxidized and the loss is large, which increases the cost of crystal growth. In 1993, Japanese scientist Y. : Mg 2 SiO 4 Laser crystal, obtained a single crystal with a size of Φ35×100mm (see prior art [1] Y.Yamaguchi, "The behavior of chromium ions in forsterite" published in the International Journal of Crystal Growth, No. 128, 1993 pp. 996-1000). In 1992, Chinese scientist Yan Shenghui and others provided a "method for protecting iridi...

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Problems solved by technology

[0002] Magnesium silicate doped with tetravalent chromium (Cr 4+ : Mg 2 SiO 4 ) crystals must be grown in an oxidizing atmosphere, but in an oxidizing atmosphere, the iridium crucible is severely oxidized and the loss is large, which increases the cost of crystal growth. In 1993, Japanese scientist Y.Yamaguchi et al. reported that high-quality Cr : Mg 2 SiO 4 Laser crystals, obtained a single crystal with a size of Φ35×100mm (see prior art [1] Y.Yamaguchi, "The behavior of chromium ions in forsterite" published in the International Journal of Crystal Growth, No. 128, 1993 pp. 996-1000)

In 1992, Chinese scientist Yan Shenghui and others provided a "method for protecting iridium crucibles from growing tetravalent chromium-doped high-temperature oxide crystals", application number 92108460.9, publication number CN1080334A, which used plasma spraying technology to spray a zirconia protective layer on the outer wall of iridium crucibles. The method of chemicalizing materials under a neutral atmosphere and maintaining the growth of crystals under an oxygen atmosphere greatly reduces the iridium volatilization loss, and the single growth loss is about 6 grams, but this method has obvious disadvantages: (1) the zirconia coating is easy During growth, especially when the temperature rises and falls, the crucible will be separated from the crucible when the temperature changes greatly, which will cause serious loss of the iridium crucible; (2) the oxygen-containing time in the atmosphere during the crystal growth stage is too long, and the loss of the iridium crucible is still large; (3) at the beginning The oxygen content in the stage is sufficient, and with the consumption of oxygen content, the Cr in the crystal 4+ The ion concentration is getting lower and lower, making the concentration extremely uneven, which not only affects the availability of the crystal, but also due to Cr 4+ The inhomogeneity of ion concentration seriously affects the laser performance of the crystal

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