Sievert’s constant

The hydrogen-in-lead data were converted to deuterium-in-lead data by assuming that the ratio of Sievert s constants for hydrogen and deuterium is constant (independent of the Pb-Li composition) and by using the Argonne data for hydrogen and deuterium in pure lithium. The adjustment was relatively small, with a 9% increase at 767 C and a 20% increase at 477°C. 

For unsaturated solutions the amount of hydrogen in solution is governed by the pressure. Over this region the Sievert s constant, K, is slightly affected by temperature and is given by the equation 32... 

Apparatus. The hydrogen-absorption system, a modified Sievert s apparatus, consisted of three self-contained units. The first unit provided a source of, and storage facilities for, pure hydrogen, which was obtained by the thermal decomposition of uranium hydride. The second unit provided precise metering of hydrogen at a known temperature, for delivery to the reaction system. The third unit was a constant-volume section in which the reaction of hydrogen with the zirconium-uranium alloy occurred at a controlled temperature ( 3° C.). The equilibrium pressures of hydrogen were measured in this section also. 

Fig. 4.7 (a) Calibration data shown as responses to injections of Hoover a large range of concentrations showing a limit of detection of approximately 100 ppm. (b) Linear calibration plot showing the expected square root dependence as described by Sievert s law and a regression constant of 0.992 (Reprinted with permission from Patton et al. (2010). Copyright 2010 Elsevier)... 

The hydrogen flux through the membrane is proportional to the diffusion coefficient Dh of hydrogen in palladium and Sievert s solubility constant Ks of the hydrogen/palladium system ... 

Consider that a bath of liquid Fe is equilibrated with a hydrogen atmosphere at an elevated temperature and dissolves 2 X 10 wt% H. The liquid is rapidly cooled to 1,540 °C, at which temperature the Sievert s-law constant is 2.3 x 10 wt% H/atm, and hydrogen bubbles are nucleated. Calculate the minimum bubble size which is stable at a depth of 1 m below the bath surface. 

From the above it is clear that the value of K is substantially constant, and therefore the solubility of oxygen in silver at 1075°C obeys Sievert s law. 

DSC tests show a substantial reduction of the hydrogen desorption onset (red circles) (T J and peak (T ) temperatures due to the catalytic effects of n-Ni as compared to the hydrogen desorption from pure MgH also milled for 15 min. (Fig. 2.57). It is interesting to note that there is no measurable difference between spherical (Fig. 2.57a) and fdamentary (Fig. 2.57b) n-Ni, although there seems to be some effect of SSA. We also conducted desorption tests in a Sieverts apparatus for each SSA and obtained kinetic curves (Fig. 2.58), from which the rate constant, k, in the JMAK equation was calculated. The enhancement of desorption rate by n-Ni is clearly seen. At the temperature of 275°C, which is close to the equilibrium at atmospheric pressure (0.1 MPa), all samples desorb from 4 to 5.5 wt.% within 2,000 s. 

The solubility of the isotopes in palladium has been made the subject of an experimental study by Sieverts and his co-workers (2i), and shows that in an equilibrium system there are considerable solubility differences. Sieverts and Danz s (2i) results are shown in Fig. 40. The higher temperature results, where Nernst s distribution law, 8 = k p, may be expected to hold (>S denotes the solubility and i is a constant), lead to the following solubility ratios at one atmosphere pressure ... 

---