The Phase Diagram and Superabundant Vacancy Formation in Co—H Alloys

Abstract

Equilibria E 4000The Phase Diagram and Superabundant Vacancy Formation in Co-H Alloys -[XRD study at up to 1300°C and hydrogen pressures up to 7.4 GPa]. -(FUKAI*, Y.; YOKOTA, S.; YANAGAWA, J.; J. Alloys Compd. 407 (2006) 1-2, 16-24; Dep. Phys., Chuo Univ., Bunkyo, Tokyo 112, Japan; Eng.) -Schramke 11-011

The structure and phase diagram of M–H systems at high chemical potentials—High pressure and electrochemical synthesis

“…The supercritical anomaly similar to Figs. 12 and 13 was also observed in the Co-H system, and a hypothetical critical point was roughly located at p c = 5.5-6 GPa and T c ≤ 300 • C, which is actually in the hcp region [23]. …”

“…9 for the Fe-H system [22], Fig. 10 for the Co-H system [23] and Fig. 11 for the Ni-H system [24,25].…”

Enhanced moments of Eu in single crystals of the metallic helical antiferromagnetEuCo2−yAs2

“…For some crystal growths, the Co powder was additionally heated under a flow of H 2 gas under a pressure of 12 bar at a temperature of 324 • C for 12 h to remove possible surface oxidation. At this H 2 pressure and temperature, negligible H is absorbed by the Co [49]. Single crystals were grown in both Sn flux and CoAs flux using both H 2 -treated and as-received Co powder.…”

Defects in Metals

“…The high concentration of vacancies has immediate impact on substitutional diffusion (Hayashi et al, 1998;Iida et al, 2005) and is therefore of practical importance. There is ample evidence that interstitial hydrogen atoms attract vacancies to form clusters, with a binding energy of 0.3 to 0.4 eV, and considerably reduce the effective formation energy of vacancies (Harada et al, 2005;Hiroi et al, 2005;Fukai et al, 2006). The entire picture is supported by ab initio calculations (Tateyama and Ohno, 2003;Nazarov et al, 2010).…”