Light weight hydrogen storage alloys represented by Mg-RE-based metal hydrides have shown broad application prospects in hydrogen energy storage and new energy applications due to their light weight abundant resources and potential high thermal conductivity. The Mg90Ni5(La,Ce)5 alloy ingots were prepared via induction suspension melting. After mechanical crushing and sieving, powders with particle sizes ranging from approximately 50 μm to 600 μm were obtained. Subsequently, the powders were compacted into pelletized samples to investigate the effect of particle size on the thermal conductivity of the samples was evaluated using the TC3100 hot wire method calorimeter and the LFA467 laser flash method apparatus. The microstructures of the powders and alloy specimens were characterized by scanning electron microscopy. Results indicated that in the powder state, the thermal conductivity of the alloy powder with a peak particle size of 173 μm was significantly higher than that of the 56 μm powder. Under the tablet-pressing condition, the thermal conductivity of the 173 μm alloy pellet is 18.88 W/(m·K), whereas that of the 56 μm alloy pellet is 9.11 W/(m·K). At 298 K, the thermal conductivity of the 173 μm alloy powder is 0.18 W/(m·K), whereas that of the 56 μm alloy powder is 0.14 W/(m·K). Regardless of whether the samples were in powder or compact form, the thermal conductivity increased with rising temperature at a given particle size. Upon consolidation into pellets, the thermal conductivity of the Mg90Ni5(La,Ce)5 alloy powder is significantly enhanced. When the temperature reaches 373 K, the thermal conductivity of the 173 μm alloy powder is only 0.20 W/(m·K). However, after consolidation into pellets, its thermal conductivity increases to 20.26 W/(m·K).
WU et al. (Mon,) studied this question.