2017 年 81 巻 4 号 p. 192-195
We have presented a novel method for the production of gold micrometer-sized particles by dissolving and recovering gold with DMSO/HCl containing CuCl2 and NaCl. It was reported that spherical or confeito-like particles could be formed depending on the concentrations of dissolved gold and Cl- ion in the liquid. In this paper, in-situ observation for the formations of gold particles in the liquid phase was conducted using atmospheric scanning electron microscopy (ASEM). An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. This structure of ASEM enable us to observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. It was found that all of the particles formed during in-situ observation were confeito-like in shape, which was different from what had been expected.
