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人工晶体学报 ›› 2024, Vol. 53 ›› Issue (7): 1186-1195.

• 研究论文 • 上一篇    下一篇

Al-50%Si合金电磁定向凝固提纯过程中初晶硅富集行为研究

刘家旭, 张银涛, 唐洪, 陈嘉慧, 陈广玉, 何占伟, 赵紫薇, 高忙忙   

  1. 宁夏大学材料与新能源学院,宁夏光伏材料重点实验室,银川 750021
  • 收稿日期:2024-03-03 出版日期:2024-07-15 发布日期:2024-07-23
  • 通信作者: 高忙忙,博士,研究员。E-mail:gaomm@nxu.edu.cn
  • 作者简介:刘家旭(1995—),男,山东省人,硕士研究生。E-mail:15006615491@163.com
  • 基金资助:
    国家自然科学基金(52164047);中国科学院“西部之光”人才培养计划(XAB2022YW10);宁夏自然科学基金(2021AAC03064)

Effect of Electromagnetic Directional Solidification and Purification on Primary Silicon Enrichment Behavior in Al-50%Si Alloy

LIU Jiaxu, ZHANG Yintao, TANG Hong, CHEN Jiahui, CHEN Guangyu, HE Zhanwei, ZHAO Ziwei, GAO Mangmang   

  1. Ningxia Key Laboratory of Photovoltaic Materials, School of Materials and New Energy, Ningxia University, Yinchuan 750021, China
  • Received:2024-03-03 Online:2024-07-15 Published:2024-07-23

摘要: 采用Al-Si合金提纯制备多晶硅过程中,初晶硅的富集可以有效减少后续酸洗过程中铝和酸的消耗,进而降低高纯初晶硅的分离成本。电磁定向凝固具有工艺简单、可控性强等优点,是目前提纯制备多晶硅最佳方法之一,但各工艺参数对初晶硅的富集影响规律还缺乏系统研究。为此,本文研究了初始凝固温度、坩埚初始位置和下移速率对Al-50%Si(质量分数)合金凝固过程中初晶硅富集行为的影响,并对富集区内初晶硅晶粒的形貌进行了表征。结果表明,初始凝固温度为950 ℃,坩埚初始位置为-5 mm及坩埚下移速率为2 mm/h时,初晶硅主要富集在铸锭的下部区域,最高富集率为79.1%,是最佳的工艺组合。同时,随着初晶硅富集程度的增加,初晶硅晶粒由盘片状向粗大的球状转变,这有利于降低初晶硅的夹杂,并提高其纯度。

关键词: Al-Si合金, 电磁定向凝固, 初晶硅, 硅富集, 温度梯度, 初晶硅形貌

Abstract: In the process of preparing polycrystalline silicon using Al-Si alloy purification, the enrichment of primary silicon can effectively reduce the consumption of aluminum and acid in the subsequent pickling process, thereby lowering the separation cost of high-purity primary silicon. Electromagnetic directional solidification is one of the best methods for preparing polycrystalline silicon currently due to its advantages such as simple process and strong controllability. However, there is a lack of systematic research on how various process parameters affect the enrichment of primary silicon. Therefore, this study investigates the effects of initial solidification temperature, crucible initial position, and descent rate on the behavior of primary silicon enrichment during the solidification process of Al-50%Si (mass fraction) alloy, and characterizes the morphology of primary silicon grains within the enrichment zone. The results show that when the initial solidification temperature is 950 ℃, the initial crucible position is -5 mm, and the crucible descent rate is 2 mm/h, primary silicon is mainly concentrated in the lower part of the ingot with a maximum enrichment rate of 79.1%, which is the optimal combination of processes. At the same time, as the degree of primary silicon enrichment increases, the primary silicon grains change from “disk-like” to coarse “spherical”, which helps reduce the inclusion of primary silicon and improve its purity.

Key words: Al-Si alloy, electromagnetic directional solidification, primary silicon, silicon enrichment, temperature gradient, primary silicon morphology

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