The electrochemical performance of melt-spun C14-Laves type Ti Zr-based alloy

Abstract

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 Ti 12 Zr 21.5 V 10 Cr 7.5 Mn 8.1 Co 8 Ni 32.2 Al 0.4 Sn 0.3. 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 capac ities exceeding 400 mAh•g 1 were achieved for the melt spun samples during the measure ments 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.

Studies of the effect of melt spinning on the electrochemical properties of the AB2 Laves phase alloys

“…Further details concerning the chemical compositions of the studied samples can be found elsewhere [9,10]. The alloys were prepared by a rapid solidification technique with an Edmund Buehler melt spinner (Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB, France)) with the wheel rotation speeds of 630, 2100, and 4100 cm/s.…”

“…The electrochemical characterization was carried out with a three-electrode-based CT 2001 Land Battery Tester,. The test details can be found elsewhere [9][10][11][12][13].…”

“…Figure 1. shows the phase compositions of the ascast and melt-spun samples with the C14-and C15-type alloys as obtained from the Rietveld refinements [9,10]. For the C14-type alloys, the higher speed of the melt spinner resulted in a larger abundance of the C14 phase which is probably caused by the tendency of the C14 Laves phase to preferably form at higher rotation wheel speeds and higher solidification rates [12].…”

“…Table 1. The relationship between the grain size of the melt-spun alloys and the speed of the spinning wheel [9,10].…”

“…In this study, a comparative overview of the melt spinning effects on C14-and C15-type alloys is presented [9,10]. The comparison included the analysis of the samples phase compositions, microstructural properties and their electrochemical performances The present study provides a broad overview of the studied melt spun inter-metallics based on which a general relationship between the applied synthesis technique and the properties of the investigated materials, is established.…”