The carbon contamination of alloys prepared by the electro graphite crucible is impossible to avoid due to an inherit reaction between the melt and the carbon. In this study, the TiFe-based alloy is prepared by VIM process using CaO crucible as well as the electro graphite crucible. The samples are examined by means of Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive Spectrometer (EDS), and the PCT curves are also measured. It is resulted that, the oxygen content of alloys melted by CaO crucible is almost equal to the one by the graphite crucible without the carbon contamination, meanwhile the carbon content of alloys obtained by the electro graphite crucible is 1860ppm,which exceeds the tolerance of the commercial alloy (1000ppm); The microstructure of the alloy melted by CaO crucible is dendrite, but the one by the graphite crucible is composed of the equiaxed crystal with the lamellar structure and the spherical TiC particles distributed along grain boundaries or within the grain; the interfacial reaction of the electro graphite crucible with TiFe alloy melt is serious and the layer between the melt and the electro graphite crucible is formed up to 200�m in thickness, the carbon in TiFe-based alloys forms TiC. The hydrogen desorption plateau pressure of alloys melted by CaO crucible is (0.11~0.4)�105 Pa, and that by the graphite crucible is (0.6~1)�105 Pa, this may imply that the CaO crucible may be the promissing candidate for melting the high performance TiFe based hydrogen storage alloys.

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

247th National Meeting (2014)

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