A multi-slice sliding cell technique for diffusion measurements in liquid metals

Abstract

The long capillary and shear-cell techniques are traditionally used for diffusion measurements in liquid metals. Inspired by the idea of the shear-cell method, we have built a multi-slice sliding cell device for inter-diffusion measurements in liquid metals. The device is designed based on a linear sliding movement rather than a rotational shearing as used in the traditional shear-cell method. Compared with the normal shear-cell method, the present device is a more compact setup thus easier to handle. Also, it is expected to be easier to monitor with X-rays or neutrons if used in in situ experiments. A series of benchmark time-dependent diffusion experiments in Al-Cu melts carried out with the present technique reveal that accurate diffusion constants can be achieved only after a sufficient time. For short annealing times, the initial shearing process causing convective flow dominates the measurement and leads to an increase of the measured diffusion coefficient by a factor three. The diffusion data obtained for Al-Cu liquids are consistent with the most accurate data measured by the in situ X-ray radiography method under well controlled conditions of no temperature gradient or other perturbation. High accuracy and easy handling as well as superior adaptability make the present technique suitable for diffusion studies in liquid metals.

High-resolution laser spectroscopy of the linear SiC2Si molecule and its astrophysical implications

“…The experiment setup is described in Zhang et al (2017) and Zhao et al (2011). In brief, small silicon-carbon clusters are produced by discharging a SiH 4 :C 2 H 2 :Ar (∼5:2:1000) gas mixture using a slit discharge nozzle that is constructed following the design by Motylewski & Linnartz (1999).…”

In-situ X-ray monitoring of solidification and related processes of metal alloys

“…Later on, it was shown that disturbing effects, arising from bubble formation or incomplete contacts between the samples and/or container walls, may still persist and can lead to large deviations in the diffusion coefficients from their real value 49 . Hence, further improvements were devised by not only using long-capillaries with X-ray radioscopy but to develop suitable X-ray transparent linear shear/sliding cell furnaces 50 – 52 . It was recently demonstrated that in-situ monitoring the diffusion process by X-ray radioscopy enables us to determine chemical and Soret-diffusion coefficients in binary metallic alloys directly 53 .…”

Self-Diffusion in Liquid Copper, Silver, and Gold

“…An experimental study of diffusion properties in metal melts is a hard task. Progress in this field is connected with the arising of new techniques in the last two decades [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In particular, modern precise measurements provided a finding that small additions in dilute germanium weakly affect its diffusion coefficients in spite of the very big difference between their atomic mass [20].…”