Microstructure Related Hydrogen Storage Capacity of Cast Mischmetal-Nickel Alloys Substituted with Aluminium, Manganese and Tin

Abstract

The morphology and compositions of the phases present in the microstructure of cast hydrogen storage MmNi_5-xAl_x (x= 0.4 and 0.8) MmNi_4.6 Sno₄ Mn, alloys (Mm = Indian Mischmetal) have been studied. Al, Mn and Sn substitutions for Ni in MmNis produce two-phase microstructures. The hydrogen storage capacity of these alloys is related with the volume fraction of the matrix phase. Higher the matrix volume fraction, higher the hydrogen storage capacity. The hydride forming elements that constitute Mm are present in greater proportion in the major constituent matrix phase of the two-phase structure. Only trace amounts of these elements are found in the precipitate phase in the Al- and Mn substituted alloys. However, for the Sn-substituted composition, the proportion of these elements is nearly same in matrix and precipitate phase.

Keywords:

• Hydrogen storage
• Substituted alloys
• Mischmetal
• Intermetallic compound