Damage mechanism of inner heat shield of sapphire single crystal furnace

The relationships of the evaporation rate, the saturated vapor pressure, and the working temperature of Mo in vacuum environment were investigated, and the damage mechanism of Mo inner heat shield in sapphire single crystal furnace was discussed. In the results, the core operating temperature of the...

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Main Author: LIAO Bin-bin
Format: Article
Language:zho
Published: Editorial Office of Powder Metallurgy Technology 2021-06-01
Series:Fenmo yejin jishu
Subjects:
Online Access:https://pmt.ustb.edu.cn/article/doi/10.19591/j.cnki.cn11-1974/tf.2021030017
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author LIAO Bin-bin
author_facet LIAO Bin-bin
author_sort LIAO Bin-bin
collection DOAJ
description The relationships of the evaporation rate, the saturated vapor pressure, and the working temperature of Mo in vacuum environment were investigated, and the damage mechanism of Mo inner heat shield in sapphire single crystal furnace was discussed. In the results, the core operating temperature of the sapphire single crystal furnace is above 2100 ℃, the high temperature period of each cycle is more than 120 h, and the inner heat shield evaporates in the high vacuum environment. It can be seen from the microstructure that the surface of Mo sheet is loose and porous, and the sheet thickness gradually becomes thin and peels off, losing the heat insulation effect. The formula of the thickness change due to the metal evaporation is deduced from the evaporation rate, the saturated vapor pressure, and the working time at high temperatures. The thickness change trend on the inner heat shield of sapphire single crystal furnace calculated by the formula coincides with the actual service life. Since the melting point of W metal is higher than that of Mo metal, it will hardly evaporate and become thinner under the most severe working conditions in the sapphire crystal furnace according to the calculation results by the formula. Therefore, W is an ideal substitute of the inner heat shield.
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institution Kabale University
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language zho
publishDate 2021-06-01
publisher Editorial Office of Powder Metallurgy Technology
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spelling doaj-art-9ed5ee17a7a54c77a776950d0b90d6b32024-12-12T03:29:57ZzhoEditorial Office of Powder Metallurgy TechnologyFenmo yejin jishu1001-37842021-06-0139322923310.19591/j.cnki.cn11-1974/tf.2021030017Damage mechanism of inner heat shield of sapphire single crystal furnaceLIAO Bin-binThe relationships of the evaporation rate, the saturated vapor pressure, and the working temperature of Mo in vacuum environment were investigated, and the damage mechanism of Mo inner heat shield in sapphire single crystal furnace was discussed. In the results, the core operating temperature of the sapphire single crystal furnace is above 2100 ℃, the high temperature period of each cycle is more than 120 h, and the inner heat shield evaporates in the high vacuum environment. It can be seen from the microstructure that the surface of Mo sheet is loose and porous, and the sheet thickness gradually becomes thin and peels off, losing the heat insulation effect. The formula of the thickness change due to the metal evaporation is deduced from the evaporation rate, the saturated vapor pressure, and the working time at high temperatures. The thickness change trend on the inner heat shield of sapphire single crystal furnace calculated by the formula coincides with the actual service life. Since the melting point of W metal is higher than that of Mo metal, it will hardly evaporate and become thinner under the most severe working conditions in the sapphire crystal furnace according to the calculation results by the formula. Therefore, W is an ideal substitute of the inner heat shield.https://pmt.ustb.edu.cn/article/doi/10.19591/j.cnki.cn11-1974/tf.2021030017sapphireheat shieldmolybdenumvacuumevaporate
spellingShingle LIAO Bin-bin
Damage mechanism of inner heat shield of sapphire single crystal furnace
Fenmo yejin jishu
sapphire
heat shield
molybdenum
vacuum
evaporate
title Damage mechanism of inner heat shield of sapphire single crystal furnace
title_full Damage mechanism of inner heat shield of sapphire single crystal furnace
title_fullStr Damage mechanism of inner heat shield of sapphire single crystal furnace
title_full_unstemmed Damage mechanism of inner heat shield of sapphire single crystal furnace
title_short Damage mechanism of inner heat shield of sapphire single crystal furnace
title_sort damage mechanism of inner heat shield of sapphire single crystal furnace
topic sapphire
heat shield
molybdenum
vacuum
evaporate
url https://pmt.ustb.edu.cn/article/doi/10.19591/j.cnki.cn11-1974/tf.2021030017
work_keys_str_mv AT liaobinbin damagemechanismofinnerheatshieldofsapphiresinglecrystalfurnace