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用真空电弧熔炼制备AB2型Sc0.8Zr0.1Y0.1Mn2-xNix(x=0~2.0)储氢合金,利用X射线衍射(XRD)和扫描电镜/能谱分析(SEM/EDS)研究了吸氢前后Ni元素替代Mn对Sc Mn2基合金微观结构的影响,用Sievert装置和热重-差热分析仪(TG/DSC)测试了合金的压力-组成-温度(P-C-T)曲线和吸放氢动力学。研究结果表明,合金铸态组织主要由Laves主相和少量Sc Ni及富Y的第二相组成,其中稀土Sc和Y元素易与Ni形成相应的金属间化合物相。随Ni含量x的增加,合金基体的Laves相组织结构由C14型向C15型转变,x=0时,合金组织基本为C14型Laves相单相组织,x=2.0时,合金组织则完全转变为C15型Laves相单相组织。Ni元素替代Mn对合金的气态吸放氢动力学行为和吸氢P-CT曲线影响较大。随Ni含量的增加,合金吸氢动力学与活化性能逐渐变慢,但其放氢温度明显降低,氢化物生成焓减小(-35.05~-18.72k J·mol-1),储氢平台压升高,储氢容量降低;室温时合金最大储氢量达2.18%(质量分数),储氢后其晶格膨胀率ΔV/V为10.63%~27.32%,吸氢前后合金主相仍保持C14型或C15型相结构,并未发生新的氢致相变,亦无氢致非晶化现象。
AB2-type hydrogen storage alloys Sc0.8Zr0.1Y0.1Mn2-xNix (x = 0 ~ 2.0) were prepared by vacuum arc melting. The hydrogen absorption properties of hydrogen storage alloys were studied by X-ray diffraction and scanning electron microscopy (SEM / EDS) The effect of Ni substitution on Mn microstructure of Sc Mn2-based alloys was investigated. The pressure-composition-temperature (PCT) curves and hydrogen absorption and desorption kinetics of the alloys were tested by Sievert apparatus and TG / DSC. . The results show that the as-cast alloy mainly consists of Laves main phase, a small amount of Sc Ni and a Y-rich second phase, in which rare earth elements Sc and Y easily form the intermetallic phase with Ni. With the increase of Ni content, the Laves phase structure of the alloy matrix changes from C14 to C15. When x = 0, the alloy structure is basically C14 Laves phase single phase structure. When x = 2.0, the alloy structure completely changes to C15-type Laves phase single-phase tissue. The effect of Ni substitution on Mn on the kinetics of hydrogen storage and desorption of hydrogen and hydrogen absorption P-CT curves is greatly affected. With the increase of Ni content, the hydrogen absorption kinetics and activation properties of the alloy gradually slow down, but the hydrogen desorption temperature was significantly reduced, the hydride formation enthalpy decreased (-35.05 ~ -18.72k J · mol-1), hydrogen storage platform pressure The maximum hydrogen storage capacity of the alloy reaches 2.18% (mass fraction) at room temperature, the lattice expansion rate ΔV / V is 10.63% -27.32% after hydrogen storage, and the main phase of the alloy remains C14 Type or C15 type phase structure, did not occur new hydrogen induced phase change, nor hydrogen induced amorphization.