HYDROGEN INTERACTION WITH RNI(3) TYPE INTERMETALLIC COMPOUNDS AT HIGHGASEOUS PRESSURE

Pressure-composition isotherms for CeNi3-H-2, CeNi2.2Mn0.8-H-2 and ErN i3-H-2 systems were measured at pressures up to 2000 atm and at temper atures from -78 degrees C to 23 degrees C, New hydride phases RNi(3)H( 5.5-5.6) were synthesized and characterized by X-ray diffraction. Ther modynamic parameters of formation-decomposition reactions at low tempe rature for intermediate ErNi3H4 phase were calculated as Delta H = 23. 8 kJ mol(-1) and Delta S - 103 J K-1 mol(-1). The phenomenon of irreve rsible hydrogen absorption at high pressure was found for all studied systems. Thermal desorption peculiarities for CeNi3Hx and ErNi3Hx hydr ides were determined. Copyright (C) 1996 International Association for Hydrogen Energy