DEVELOPMENT OF HYDROGEN-ABSORBING RARE-EARTH NI-ALLOYS FOR A -20-DEGREES-C REFRIGERATION SYSTEM

The equilibrium and reaction rate performance of pseudo-binary La1-xYxNi5-yMny (x = 0-0.4; y = 0-0.2) alloys were investigated with regard to their use in a -20-degrees-C refrigeration system with a 130-150-degrees-C thermally driven heat source, such as solar heat. The substitution of Mn for Ni in LaNi5 improved the reaction rate, while substitution of Y for La raised the equilibrium hydrogen pressure to approximately 1 MPa at room temperature, which is ideal for a refrigeration system. As a consequence, a - 20-degrees-C refrigeration heat cycle With La0.6Y0.4Ni4.8Mn0.2 was designed successfully.