Electrochemical and electronic properties of nanocrystalline TiNi1−xMx (M=Mg, Mn, Zr; x=0, 0.125, 0.25) ternary alloys

Szajek, A.; Makowiecka, M.; Jankowska, E.; Jurczyk, M.

doi:10.1016/j.jallcom.2005.05.011

Cited by 19 publications

(15 citation statements)

References 20 publications

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“…The application of titanium alloys as electrode materials for Ni-MH batteries has recently attracted substantial interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Various alloying elements have been used to improve the electrochemical capacity and cycle life of TiNi-and TiFe-based ternary and quaternary alloys.…”

Section: Introductionmentioning

confidence: 99%

Influence of alloying and microstructure on the electrochemical hydriding of TiNi-based ternary alloys

2007

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Nanostructured ternary TiNi-type alloys, namely Ti 0.8 M 0.2 Ni (M = Zr, V), TiNi 0.8 N 0.2 (N = Cu, Mn) and TiNi 1-x Mn x (x = 0.2, 0.4, 0.6, 1.0), were synthesized by mechanical alloying. Depending on the intensity and time of milling alloys with different microstructure were obtained. The as-milled TiNi 1-x Mn x alloys contain substantial amount of amorphous phase, which crystallizes during annealing. Annealing of the as-milled fine nanocrystalline materials at 500°C results only in slight coarsening of the microstructure, which remains still nanocrystalline. Fully crystalline material (with crystal size larger than 50 nm), consisting of mainly cubic TiNi was obtained by annealing the ball-milled alloys at T C 700°C. Electrochemical hydrogen charge/discharge cycling of the as-milled as well as of annealed alloys were carried out at galvanostatic conditions. It was found that among the nanocrystalline Ti 0.8 M 0.2 Ni 0.8 N 0.2 (M = Zr, V; N = Cu, Mn) alloys TiNi 0.8 Mn 0.2 revealed the highest discharge capacity of 56 mAh g -1 in the as-milled state and 75 mAh g -1 after short-time annealing at 500°C. Annealing at higher temperature does not increase the capacity further. The as-milled TiNi 1-x Mn x alloys with x B 0.4 reveal noticeably higher discharge capacity and better cycle life than the Mn-richer alloys. Based on potentiostatic experiments the diffusion coefficients of hydrogen into TiNi alloys in two different microstructural states (fine and coarser nanocrystalline) as well as in as-milled amorphous/nanocrystalline and nanocrystalline TiNi 0.8 Mn 0.2 were determined. The hydrogen diffusion coefficients of the TiNi alloys are comparable (1.9-2.7 9 10 -12 cm 2 s -1 ). The diffusion coefficient in the as-milled amorphous/nanocrystalline TiNi 0.8 Mn 0.2 was found to be 3-4 times higher than that of the as-milled nanocrystalline alloy.

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Section: Introductionmentioning

confidence: 99%

Influence of alloying and microstructure on the electrochemical hydriding of TiNi-based ternary alloys

2007

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“…Therefore, the broadening of the experimental valence band could be explained by the specific nanostructure of the thin film samples [18][19][20][21]. Such a modification of the valence bands of nanocrystalline materials based on Ni-Ti alloys could significantly improve the discharge capacity [26]. shows the experimental UPS valence band spectrum of nanocrystalline NiTi alloy thin film.…”

Section: Resultsmentioning

confidence: 96%

XPS and UPS Valence Band Studies of Nanocrystalline Ni-Ti Alloy Thin Films

et al. 2018

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In this contribution we study valence bands of in-situ prepared nanocrystalline NiTi and Ni3Ti alloy thin films using X-ray and ultraviolet photoelectron spectroscopy. Additionally, theoretical valence band of NiTi alloy was calculated by ab-initio methods. The structure and morphology of the samples were studied by X-ray diffraction and atomic force microscopy, respectively. Furthermore, hydrogen absorption and desorption kinetics at a pressure of about 1000 mbar were studied in Pd covered nanocrystalline NiTi alloy thin film using four-point resistivity measurements. Results showed that modifications of the valence bands of the Ni-Ti thin films due nanocrystalline structure can influence on the room temperature hydrogen absorption and desorption kinetics.

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“…Furthermore, the position of the XPS valence band maximum measured for the nanocrystalline NiTi thin lm (bold solid line in Fig. 3) is shifted towards higher binding energy compared to ab initio DOS calculations [22]. Note that the theoretical calculations were performed for the perfect crystal structure.…”

Section: Methodsmentioning

confidence: 88%

“…Therefore, the shift and broadening of the experimental valence band could be explained by the specic nanocrystalline microstructure of the thin lm sample. Such a modication of the valence band of the nanocrystalline alloy compared to that measured for the polycrystalline sample could signicantly improve the discharge capacity [22].…”

Section: Methodsmentioning

confidence: 94%

Electronic Properties of In Situ Prepared Nanocrystalline Fe-Ni-Ti Alloy Thin Films

et al. 2015

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In this contribution we study experimentally the electronic properties of nanocrystalline FeNiTi alloy thin lms using X-ray photoelectron spectroscopy. The structure of the samples has been studied by X-ray diraction. Their bulk chemical compositions were measured using X-ray uorescence method. The surface chemical composition and the cleanness of all samples were checked in situ, immediately after deposition, transferring the samples to an UHV analysis chamber equipped with X-ray photoelectron spectroscopy. X-ray diraction studies revealed the formation of nanocrystalline FeNiTi alloy thin lms at a substrate temperature of about 293 K. In situ X-ray photoelectron spectroscopy studies showed that the valence bands of nanocrystalline samples are broader compared to those measured for the polycrystalline bulk alloys. Such modications of the valence bands of the nanocrystalline alloy thin lms could inuence on their hydrogenation properties.

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Electrochemical and electronic properties of nanocrystalline TiNi1−xMx (M=Mg, Mn, Zr; x=0, 0.125, 0.25) ternary alloys

Cited by 19 publications

References 20 publications

Influence of alloying and microstructure on the electrochemical hydriding of TiNi-based ternary alloys

Influence of alloying and microstructure on the electrochemical hydriding of TiNi-based ternary alloys

XPS and UPS Valence Band Studies of Nanocrystalline Ni-Ti Alloy Thin Films

Electronic Properties of In Situ Prepared Nanocrystalline Fe-Ni-Ti Alloy Thin Films

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