掺Pd改性纳米晶Mg2Ni吸放氢氘特性研究

采用机械合金化法制备了Mg2Ni-1．0％Pd（质量分数，下同）合金粉末，用XRD及AFM等分析表征了球磨20h后粉末的相结构和微观形貌，测定了Mg2Ni-1．0％Pd合金吸放氢氘的P-C-T曲线和动力学曲线。结果表明，机械合金化制备的Mg2Ni-1．0％Pd合金粉末粒度在10nm～50nm之间；同熔炼法制备的Mg2Ni合金相比，纳米Mg2Ni-1．0%Pd合金吸氢时的焓变值减小，放氢时焓变值增大，可逆贮氢容量为1．06（H／M,原子比，下同）；与吸放氢相比，在相同温度下合金吸放氘的坪台压升高，焓变值减小，具有显著的同位素效应。纳米Mg2Ni-1．0％Pd合金的吸氢速率和吸氘速率与温度的关系在573K附近发生变化。

Characteristics of the Pd-modified Nanocrystalline Mg2Ni Alloy Absorbing-Desorbing Hydrogen and Deuterium

The Mg2Ni-1.0%Pd(mass fraction)alloy power was prepared by mechanical alloying.XRD and AFM analysis were used to identify the phase and microstructure of the powder milled for 20 h.The P-C-T curves and kinetics curves of Mg2Ni-1.0%Pd-H2/D2 system were measured.The results show that the particle size of Mg2Ni-1.0%Pd alloy powder prepared by mechanical alloying was between 10 nm~50 nm.Compared with the Mg2Ni alloy prepared by melting,the enthalpy of nanocrystalline Mg2Ni-1.0%Pd alloy decreased upon hydrogen absorption and increased upon hydrogen desorption.The alloy had a reversible storage capacity as high as 1.06(H/M,atom ratio).Compared with absorbing-desorbing H2,the plateaus pressure under the same temperature increased and the enthalpy decreased on the P-C-T curves of the alloy absorbing-desorbing D2.The isotope effects in nanocrystalline Mg2Ni-1.0%Pd-H2 and D2 interaction were noticeable.The rate curves of absorbing H2 and D2 were measured at different temperatures,and the relationship of the rate and temperature changed around 573 K.