Effect of substitution on hysteresis in some high-pressure AB2 and AB5 metal hydrides

摘要: Abstract Ti 0.95 Zr 0.05 Cr 1.2 Mn 0.8− x V –H 2 ( =0, or 0.1), y Co 0.1 0.2) and Ce 0.8 La 0.2 Ni 5− z 0.5, 1.0 1.5) systems were studied experimentally in order to (a) find suitable alloys for high-pressure applications, (b) gain insight into the reasons hysteresis its reduction due certain partial substitutions. A special volumetric pressure–composition isotherm (PCI) measurement technique at high pressures (up 400 bar this case), pressure differential scanning calorimetry (PDSC), X-ray diffractometry (XRD) of both starting SO - (or air-) poisoned hydrides applied. Practically hysteresis-free alloy–hydrogen with good PCI plateau properties found, e.g. 0.75 . Furthermore, it was shown that an intermediate hydride phase 3.5 1.5 system exists, which explains remarkably reduced compared less non-substituted systems. Finally, experimental correlation between discrete unit cell volume expansion coexisting phases displayed. It suggests is a major reason hysteresis, but more data needs be collected.