Diffusion coefficients for sodium and potassium chlorides in water at elevated temperatures

1971 ◽  
Vol 16 (4) ◽  
pp. 427-429 ◽  
Author(s):  
Christopher J. D. Fell ◽  
H. Peter. Hutchison
Keyword(s):  
Diffusion Coefficients ◽  
Elevated Temperatures ◽  
Sodium And Potassium

Measurement of the diffusion coefficients of reactive species in dilute gases

1982 ◽  
Vol 380 (1779) ◽  
pp. 241-258 ◽  
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Reactive Species ◽  
Resonance Fluorescence ◽  
Hydrogen Atoms ◽  
Chromatographic Effect ◽  
Diffusion Of Hydrogen

A technique has been developed for measuring the diffusion coefficients of atoms and other reactive species in gases below atmospheric pressure. The technique consists of measuring the rate of dispersion of a pulse of reactive species in a stream of gas flowing rapidly ( ca . 10 m s -1 ) down a quartz tube. The reactive species are observed and the profile of the pulses measured by using resonance fluorescence. The technique has been used at room temperature, but in principle measurements could be made at elevated temperatures. Measurements have been made of the rates of diffusion of hydrogen atoms in argon and nitrogen, and values for the diffusion coefficients of 1.61 ± 0.04 and 1.35 ± 0.03 cm 2 s -1 respectively, at 1 atmosphere ( ca . 10 5 Pa) and 294 K, have been obtained. Incidentally to the primary purpose of the experiment, it was observed that the hydrogen atoms spend a small fraction of their time of passage along the tube reversibly adsorbed on its walls. From the measurements, both the partition coefficient, giving the ratio of hydrogen atoms on the walls to those in the gas phase, and the rates of adsorption and desorp­tion can be obtained. This appears to be the first observation of a chromatographic effect for a highly reactive species.

Diffusion of Ti, V and Nb in Ni3Al at Elevated Temperatures

2010 ◽  
Vol 297-301 ◽  
pp. 384-389 ◽  
Author(s):  
Haruhiko Fukaya ◽  
Md. Moniruzzaman ◽  
Yoshinori Murata ◽  
Masahiko Morinaga ◽  
Toshiyuki Koyama ◽  
...  
Keyword(s):  
Experimental Data ◽  
Diffusion Coefficients ◽  
Binary Systems ◽  
Elevated Temperatures ◽  
Diffusion Mechanism ◽  
Impurity Diffusion ◽  
Diffusion Couples ◽  
Different Temperatures ◽  
Series Of Experiments ◽  
Interdiffusion Coefficients

Interdiffusion coefficients of Al replacing elements in Ni-Al-X (X=Ti, V and Nb) were estimated by a series of experiments using diffusion couples of Al rich pseudo-binary systems at three different temperatures of 1423, 1473 and 1523K. In order to obtain interdiffusion coefficients of the pseudo-binary systems, the experimental data was analyzed by the Sauer and Freise method, and also impurity diffusion coefficients of Ti, V and Nb in Ni3Al were estimated by applying the Darken-Manning equation. The magnitude of interdiffusion coefficient decreased in order of V, Ti and Nb at all three temperatures. Impurity diffusion coefficients were described by the expressions: , , . The activation enthalpies obtained from the experimental data confirmed the retardation of Ti, V and Nb diffusion in Ni3Al by the anti-site diffusion mechanism. These results are consistent with our previous work on diffusion of Re and Ru in Ni3Al .

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