The electrochemical performance of melt-spun C14-Laves type TiZr-based alloy
Résumé
The main objective of the present work is to study the effect of rapid solidification on the electrochemical performance of Zr-based Laves type alloy with a nominal composition Ti12Zr21.5V10Cr7.5Mn8.1Co8Ni32.2Al0.4Sn0.3. The samples were prepared from the as-cast arc melted buttons by melt spinning at different copper wheel rotation speeds of 5, 16.5, 33, and 100 Hz, which are equivalent to linear speeds of 6.3, 21, 41, and 62.8 m s−1 respectively using a cooling wheel with a diameter of 20 cm. The phase composition and morphology of the ribbons were analyzed by X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructural changes of the ribbons induced by the variations in the wheel rotation speed were found to be closely related to the electrochemical performances. High discharge capacities exceeding 400 mAh∙g−1 were achieved for the melt spun samples during the measurements at low current densities. Furthermore, melt spun casting performed at the highest wheel rotation speed of 100 Hz resulted in the best rate performance of the alloy. As this alloy has the smallest crystallite size, this resulted in the shortest H atoms diffusion distances, and thus increased the efficient H diffusion rate and improved the electrochemical performance.
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