Effect of Hydrogen Absorption on the Electrical Resistance of Melt-Spun Mg-Pd and Mg-Ni-Pd Amorphous Alloys

Abstract

The Mg 100Àx Pd x (x ¼ 10, 20 and 30), Mg 80 Ni 20Ày Pd y (y ¼ 5 and 10) and Mg 75 Ni 20 Pd 5 amorphous alloys were prepared by the singleroller melt-spinning technique. The electrical resistance was measured during electrochemical hydrogen charging in 6N KOH solution. The Mg 90 Pd 10 amorphous alloy shows larger increase in the electrical resistance by hydrogen absorption than any other alloys prepared in this study. Moreover, the electrical resistance of those alloys was also measured in hydrogen-dissolved water prepared by the bubbling method. As a result, it was found that the electrical resistance increases with increasing immersion time and that the increase amount of the electrical resistance is dependent on the alloy composition. The increase amount of the electrical resistance of the Mg 90 Pd 10 amorphous alloy is much larger than those of other alloys prepared in this work. The increase amount of the electrical resistance of the Mg 90 Pd 10 amorphous alloy after immersion in hydrogen-dissolved water for 300 s is dependent on the concentration of hydrogen in water, and it increases with increasing hydrogen concentration in water. From these results, it is confirmed that hydrogen absorption has a great influence on the electrical resistance of the Mgbased amorphous alloys and that the sensitivity to hydrogen can change largely depending on the alloy composition even in the similar alloy systems.

X-ray Diffraction Study for Mg₄Pd Crystalline and Amorphous Alloys Using Synchrotron Radiation

“…As shown in the Mg-Pd binary phase diagram in Fig. 1, 6) the existence of a single Mg 4 Pd phase has been confirmed by some researchers. [7][8][9] According to the phase diagram, each unknown phase mentioned above is predicted as Mg 4 Pd.…”

“…Therefore, we have proposed the possibility of these amorphous alloys being applied to base materials for a hydrogen sensor in water. [1][2][3][4] In these amorphous alloys, a Mg 9 Pd amorphous alloy shows the highest sensitivity to hydrogen dissolved in water. In order to clarify the factors related to the good sensitivity to hydrogen, it is necessary to compare the structural properties among several Mg-Pd amorphous alloys.…”

Electrical Resistance Change due to Hydrogenation of Pd and Pd–Ni Thin Films Immersed in Hydrogen-Dissolved Water

“…The concentration of hydrogen introduced in the water was 1.5 ppm at maximum after bubbling for 1.5 h as reported in our early work. 9,10) The electrical resistance of the specimens in HDW was measured by the four-probe method with the current generator (ADVANTEST R6144) and the digital multi-meter (ADVANTEST R6561). In the cyclic test, the specimens were immersed in 500 ml PW and in 500 ml HDW for 10 min alternatively.…”

“…In our previous works, we measured the electrical resistance of amorphous metallic alloys immersed in HDW and reported that the electrical resistance of the melt-spun Mg-Pd amorphous ribbon-shaped specimens increased with increasing concentration of DH in HDW. 9,10) For the development of a new DH sensor, we have tried to produce thin film specimens to promote hydrogenation and dehydrogenation more quickly than ribbon specimens.…”

Alloying Effect on the Hydrogen Sensing Property of Melt-Spun Mg<SUB>90</SUB>Pd<SUB>10</SUB> Amorphous Alloy

“…[1][2][3] These amorphous alloys show increases in the electrical resistance after electrochemical hydrogen charging. When the alloys are immersed in hydrogen-dissolved water, the Mg-based amorphous alloys show increases in the electrical resistance while the others do not show any change.…”