TiFe基储氢合金的BaZrO3坩埚熔炼制备及其储氢性能

利用自制25 kg 级BaZrO3坩埚，通过ZG-0．05型真空感应熔炼制备 TiFe 基储氢合金。熔炼条件为：0．6 MPa氩气保护气氛，精炼时间5～10 min，精炼温度1450℃左右。采用ICP原子发射光谱分析仪分析所熔合金的化学成分，利用金相显微镜、扫描电子显微镜、XRD 衍射仪研究了合金的金相组织、表面形貌、微区元素分布、物相结构，用气体反应控制器测定了合金的PCT曲线。研究表明：由BaZrO3坩埚熔炼的TiFe基储氢合金氧质量分数与石墨坩埚熔炼的合金氧质量分数均小于0．1％，而石墨坩埚熔炼的合金碳质量分数为0．417％。BaZrO3坩埚熔炼后的合金完全由等轴晶构成，而石墨坩埚熔炼后的合金则由等轴晶组织和在晶粒内或沿晶界分布的球形TiC颗粒组成。BaZrO3坩埚所熔炼的合金不仅最大吸氢量比石墨坩埚熔炼的合金的最大吸氢量大，而且吸放氢平台压力也低。

Preparation of TiFe based alloys melted by BaZrO3 crucible and its hydrogen storage properties

TiFe-based hydrogen storage alloy was prepared by using a self-made 25 kg BaZrO3 crucible with ZG-0.05 type vacuum induction melting system.The melting conditions are argon atmosphere of 0.6 MPa, refining time of 5~10 min and temperature of 1 450 ℃.The chemical composition of the as-cast sample was examined by means of inductive coupled plasma emission spectrometer (ICP )first,and then its microstructure,surface topography,element distribution in micro-domains and phase were examined by optical microscopy (OM),scanning electron microscopy (SEM),X-ray diffraction (XRD)and energy dispersive spectrometer (EDS),and finally its PCT curves were measured by gas reaction controller.The results show that,the oxygen contents of alloys prepared by the BaZrO3 crucible and the graphite crucible are are less than 0 .1%(ω),meanwhile the carbon content of alloys obtained by the electro graphite crucible is 0.417%(ω),which exceeds the tolerance of commercial alloys (1 000 ppm).The microstructure of the alloy melted by the BaZrO3 crucible is equiaxed crystal,but the alloy melted by the graphite crucible is composed of the equiaxed crystal and the spherical TiC particles distributed along grain boundaries or within the grain.The maximum amount of hydrogen absorption of the alloy melted by the BaZrO3 crucible is larger than that of the alloy melted by the graphite crucible,and the hydrogen desorption and absorption plateau pressure of the alloy meted by the BaZrO3 crucible is also lower.