Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
In-Situ Observation for Formations of Gold Micrometer-Sized Particles in Liquid Phase Using Atmospheric Scanning Electron Microscopy (ASEM)
Yasunari MatsunoEri OkonogiAkihiro YoshimuraMari SatoChikara Sato
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2018 Volume 59 Issue 1 Pages 146-149


In this report, we present a novel method to produce micrometer-sized gold particles by dissolving and recovering gold from a dimethyl sulfoxide/hydrochloric acid (DMSO/HCl) solution containing copper (II) chloride (CuCl2) and sodium chloride (NaCl). It was reported that spherical or confeito-like particles can be formed depending on the concentrations of dissolved gold and Cl ions in the solution. In this paper, in-situ observation of gold particle formation in the solution phase was conducted using atmospheric scanning electron microscopy (ASEM). An electron-permeable window made of a pressure-resistant silicon nitride (Si3N4) film (100 nm-thick), was set at the bottom of the open ASEM sample dish, which facilitated the projection of electron beams from underneath the sample. This structure of ASEM enabled us to observe dynamic phenomena in liquid or gas phase under atmospheric pressure in real time. It was found during the in-situ observation that all of the particles formed were confeito-like in shape, which was different from the expected particle morphology.


This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 81 (2017) 192–195.

Fig. 7 ASEM images of gold particle formation in the liquid after 46 minutes at a magnification of ×30,000, Experiment 2. Fullsize Image
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© 2017 The Japan Institute of Metals and Materials
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