Effect of Mg alloying and cooling rate on the microstructure of silicon

In response to the escalating global demand for solar photovoltaic (PV) energy, there is a critical need for more cost-effective and environmentally sustainable production methods for upgrading metallurgical-grade silicon (MG-Si). Among various metallurgical approaches, acid leaching is an economica...

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Main Authors: Mengyi Zhu, Jafar Safarian, Mochamad Ilham Al Fariesy Irvansyah, Marisa Di Sabatino
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-03-01
Series:Frontiers in Photonics
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fphot.2024.1334122/full
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author Mengyi Zhu
Jafar Safarian
Mochamad Ilham Al Fariesy Irvansyah
Marisa Di Sabatino
author_facet Mengyi Zhu
Jafar Safarian
Mochamad Ilham Al Fariesy Irvansyah
Marisa Di Sabatino
author_sort Mengyi Zhu
collection DOAJ
description In response to the escalating global demand for solar photovoltaic (PV) energy, there is a critical need for more cost-effective and environmentally sustainable production methods for upgrading metallurgical-grade silicon (MG-Si). Among various metallurgical approaches, acid leaching is an economical and effective method to upgrade MG-Si. However, the impact of cooling rates during solidification, a potentially significant factor for optimization of the leaching process, has been rarely investigated. In this work, the effects of magnesium alloying content and cooling rate on microstructural evolutions in MG-Si are studied. MG-Si was alloyed with two different magnesium contents (5.5 wt% and 9.0 wt%), using an induction furnace for the melting, alloying, and casting process. The cast alloys were subsequently remelted under five distinct cooling rates, specifically 3, 10, 25, 40, and 80°C/min. Microstructural analysis and grain size measurement were conducted using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and the ASTM E112 standards. It was observed that the Mg2Si phase was formed along the primary Si grains and with other intermetallic silicide-containing impurities embedded inside. Moreover, higher cooling rates resulted in finer primary Si grains with highly diverse crystallographic orientations, while slower rates induced coarser Si grains and a concentrated silicide phase along the grain boundaries. Importantly, the results also indicate that a higher magnesium alloying content (9.0 wt%) led to finer grain sizes. The present work establishes links between alloying content, cooling rate, and the resulting microstructure, offering valuable insights for optimizing the alloying–leaching process.
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spelling doaj.art-b3b01f21e7f14335a364d9310afb92802024-03-04T04:52:12ZengFrontiers Media S.A.Frontiers in Photonics2673-68532024-03-01510.3389/fphot.2024.13341221334122Effect of Mg alloying and cooling rate on the microstructure of siliconMengyi ZhuJafar SafarianMochamad Ilham Al Fariesy IrvansyahMarisa Di SabatinoIn response to the escalating global demand for solar photovoltaic (PV) energy, there is a critical need for more cost-effective and environmentally sustainable production methods for upgrading metallurgical-grade silicon (MG-Si). Among various metallurgical approaches, acid leaching is an economical and effective method to upgrade MG-Si. However, the impact of cooling rates during solidification, a potentially significant factor for optimization of the leaching process, has been rarely investigated. In this work, the effects of magnesium alloying content and cooling rate on microstructural evolutions in MG-Si are studied. MG-Si was alloyed with two different magnesium contents (5.5 wt% and 9.0 wt%), using an induction furnace for the melting, alloying, and casting process. The cast alloys were subsequently remelted under five distinct cooling rates, specifically 3, 10, 25, 40, and 80°C/min. Microstructural analysis and grain size measurement were conducted using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and the ASTM E112 standards. It was observed that the Mg2Si phase was formed along the primary Si grains and with other intermetallic silicide-containing impurities embedded inside. Moreover, higher cooling rates resulted in finer primary Si grains with highly diverse crystallographic orientations, while slower rates induced coarser Si grains and a concentrated silicide phase along the grain boundaries. Importantly, the results also indicate that a higher magnesium alloying content (9.0 wt%) led to finer grain sizes. The present work establishes links between alloying content, cooling rate, and the resulting microstructure, offering valuable insights for optimizing the alloying–leaching process.https://www.frontiersin.org/articles/10.3389/fphot.2024.1334122/fullsiliconmagnesiumcooling ratemicrostructuregrain size
spellingShingle Mengyi Zhu
Jafar Safarian
Mochamad Ilham Al Fariesy Irvansyah
Marisa Di Sabatino
Effect of Mg alloying and cooling rate on the microstructure of silicon
Frontiers in Photonics
silicon
magnesium
cooling rate
microstructure
grain size
title Effect of Mg alloying and cooling rate on the microstructure of silicon
title_full Effect of Mg alloying and cooling rate on the microstructure of silicon
title_fullStr Effect of Mg alloying and cooling rate on the microstructure of silicon
title_full_unstemmed Effect of Mg alloying and cooling rate on the microstructure of silicon
title_short Effect of Mg alloying and cooling rate on the microstructure of silicon
title_sort effect of mg alloying and cooling rate on the microstructure of silicon
topic silicon
magnesium
cooling rate
microstructure
grain size
url https://www.frontiersin.org/articles/10.3389/fphot.2024.1334122/full
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AT jafarsafarian effectofmgalloyingandcoolingrateonthemicrostructureofsilicon
AT mochamadilhamalfariesyirvansyah effectofmgalloyingandcoolingrateonthemicrostructureofsilicon
AT marisadisabatino effectofmgalloyingandcoolingrateonthemicrostructureofsilicon