Abstract
Mg2(Fe0.5Co0.5) elemental powder mixtures were processed by reactive ball milling in aH2 (orD2) atmosphere at about 50 bar. The changes of pressure were monitored during millingand hydrogen absorption was detected within the first 10 h of milling. X-ray andneutron powder diffraction analysis, followed by Rietveld refinement, suggests analmost complete conversion of the starting metals into the quaternary hydrideMg2(FeH6)0.5(CoH5)0.5. The latter has acubic K2PtCl6-type structure(space group Fm3m) witha cell parameter a≈6.42 Å. Fe and Co atoms are disorderly distributed in the 4a position. Hydrogen desorption uponheating was investigated by both in situ x-ray diffraction and temperature programmeddesorption analysis. Hydrogen is released in a one-step desorption reaction at temperaturesbetween 500 and 600 K, with Mg and a FeCo solid solution as desorption products. Finally,Mg2(FeH6)0.5(CoH5)0.5 was also synthesized by ball milling equi-molar mixtures ofMg2FeH6 andMg2CoH5 in Ar.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
