Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles

We investigated the morphological patterns, crystalline structures and their thermal stability in solidified Au–Ge nanoparticles ranging in size from 10 to 500 nm. Liquid Au–Ge alloy nanoparticles with hypoeutectic composition were rapidly cooled from a temperature of 500 °C in a TEM and characteriz...

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Main Authors: Olha Khshanovska, Vladyslav Ovsynskyi, Aleksandr Kryshtal
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/12/924
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author Olha Khshanovska
Vladyslav Ovsynskyi
Aleksandr Kryshtal
author_facet Olha Khshanovska
Vladyslav Ovsynskyi
Aleksandr Kryshtal
author_sort Olha Khshanovska
collection DOAJ
description We investigated the morphological patterns, crystalline structures and their thermal stability in solidified Au–Ge nanoparticles ranging in size from 10 to 500 nm. Liquid Au–Ge alloy nanoparticles with hypoeutectic composition were rapidly cooled from a temperature of 500 °C in a TEM and characterized using advanced TEM techniques. We demonstrated that Au–Ge nanoparticles 10–80 nm in size predominantly solidified into a Janus-like morphology with nearly pure single-crystalline hcp Au and diamond cubic Ge domains. These particles remained stable up to the eutectic temperature, indicating that Ge doping and particle size play key roles in stabilizing the hcp Au phase. In turn, larger nanoparticles exhibited a metastable core–shell morphology with polycrystalline Ge shell and hcp Au-Ge alloy core under solidification. It was shown that the mentioned morphology and crystalline structure evolved into the equilibrium Janus morphology with fcc Au and diamond Ge domains at temperatures above ≈160 °C.
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spelling doaj-art-a1daa91c75c0437fb3cf5dbe7d2f9e282025-08-20T03:16:21ZengMDPI AGNanomaterials2079-49912025-06-01151292410.3390/nano15120924Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge NanoparticlesOlha Khshanovska0Vladyslav Ovsynskyi1Aleksandr Kryshtal2Faculty of Metals Engineering and Industrial Computer Science, AGH University of Krakow, 30-059 Krakow, PolandFaculty of Metals Engineering and Industrial Computer Science, AGH University of Krakow, 30-059 Krakow, PolandFaculty of Metals Engineering and Industrial Computer Science, AGH University of Krakow, 30-059 Krakow, PolandWe investigated the morphological patterns, crystalline structures and their thermal stability in solidified Au–Ge nanoparticles ranging in size from 10 to 500 nm. Liquid Au–Ge alloy nanoparticles with hypoeutectic composition were rapidly cooled from a temperature of 500 °C in a TEM and characterized using advanced TEM techniques. We demonstrated that Au–Ge nanoparticles 10–80 nm in size predominantly solidified into a Janus-like morphology with nearly pure single-crystalline hcp Au and diamond cubic Ge domains. These particles remained stable up to the eutectic temperature, indicating that Ge doping and particle size play key roles in stabilizing the hcp Au phase. In turn, larger nanoparticles exhibited a metastable core–shell morphology with polycrystalline Ge shell and hcp Au-Ge alloy core under solidification. It was shown that the mentioned morphology and crystalline structure evolved into the equilibrium Janus morphology with fcc Au and diamond Ge domains at temperatures above ≈160 °C.https://www.mdpi.com/2079-4991/15/12/924hcp AusolidificationTEMalloy nanoparticlesmixing patterns
spellingShingle Olha Khshanovska
Vladyslav Ovsynskyi
Aleksandr Kryshtal
Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles
Nanomaterials
hcp Au
solidification
TEM
alloy nanoparticles
mixing patterns
title Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles
title_full Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles
title_fullStr Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles
title_full_unstemmed Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles
title_short Effect of Size on Phase Mixing Patterns in Rapidly Solidified Au–Ge Nanoparticles
title_sort effect of size on phase mixing patterns in rapidly solidified au ge nanoparticles
topic hcp Au
solidification
TEM
alloy nanoparticles
mixing patterns
url https://www.mdpi.com/2079-4991/15/12/924
work_keys_str_mv AT olhakhshanovska effectofsizeonphasemixingpatternsinrapidlysolidifiedaugenanoparticles
AT vladyslavovsynskyi effectofsizeonphasemixingpatternsinrapidlysolidifiedaugenanoparticles
AT aleksandrkryshtal effectofsizeonphasemixingpatternsinrapidlysolidifiedaugenanoparticles