Dataset - Multi-scale characterization of AlCoCrFeNi and AlCoCrFeNiB0.1 high entropy alloys

This data-set includes the XRD raw data presented in the article "Multi-scale characterization of AlCoCrFeNi and AlCoCrFeNiB0.1 high entropy alloys" submitted to Materials Characterization in August 20th

Review and outlook on high-entropy alloys for hydrogen storage

Recently, a new class of alloys, namely, high-entropy alloys (HEAs), started to be investigated for hydrogen storage as they can form metal hydrides. Considering that the properties of metal hydrides are greatly influenced by the type of phase formed, and chemical composition, HEAs (with their vastness of compositions) present a high potential for developing promising materials for this application. A crucial aspect in assessing the potential of these alloys is the effective compositional design and synthesis. Here, we evaluate the methods used for obtaining HEAs for hydrogen storage and, based on the most advanced discussions of phase formation and stability in HEAs, we expose some strategies for a better assessment of the vast compositional field. Moreover, we present and discuss the first attempts to model the hydrogenation properties of HEAs using thermodynamics and data science. The development of these kinds of predictive tools is paramount for exploring HEAs' potential for hydrogen storage. To date, the most promising HEA compositions can be classified into three classes: body-centered cubic HEAs, lightweight HEAs, and intermetallic HEAs

Controlled Mechanochemical Synthesis And Hydrogen Desorption Mechanisms Of Nanostructured Mg2coh5

Magnesium complex hydrides are attractive for hydrogen storage applications, mainly due to their high volumetric capacities and to their relatively low cost. In this work, nanocrystalline Mg2CoH5 was synthesized with very high yields (97%) by reactive milling cobalt and magnesium under relatively mild processing conditions (30 bar of H2 pressure and 12 h of milling). The behavior of the milled Mg2CoH5 during heating was studied by a combination of several techniques including DSC, QMS, TGA and in-situ synchrotron XRD. It is shown for the first time that two different mechanisms of hydrogen desorption take place. At low temperatures (up to 325°C), some hydrogen is released by a diffusional mechanism with no change in the crystalline structure of the high temperature γ-Mg2CoH5 phase. At higher temperatures, above 325°C, the γ-Mg2CoH5 phase becomes unstable and the complex hydride decomposes into Mg, Co and H2. This is the first work to report the diffusional hydrogen desorption mechanism for the Mg2CoH5 or any other complex hydride. Furthermore, a complete description of the allotropic β-Mg2CoH5 to γ-Mg2CoH5 phase transition is provided.40315041515Satyapal, S., Petrovic, J., Read, C., Thomas, G., Ordaz, G., The US Department of Energy 's National Hydrogen Storage Project: Progress towards meeting hydrogen-powered vehicle requirements (2007) Catal Today, 120, pp. 246-256Huot, J., Ravnsbaek, D.B., Zhang, J., Cuevas, F., Latroche, M., Jensen, T.R., Mechanochemical synthesis of hydrogen storage materials (2013) Prog Mater Sci, 58, pp. 30-75Yvon, K., Complex transition-metal hydrides (1998) Chimia, 52, pp. 613-619Zolliker, P., Yvon, K., Fischer, P., Schefer, J., Dimagnesium cobalt(I) pentahydride, Mg2CoH5, containing square-pyramidal CoH5 4- anions (1985) Inorg Chem, 24, pp. 4177-4180Huot, J., Hayakawa, H., Akiba, E., Preparation of the hydrides Mg2FeH6 and Mg2CoH5 by mechanical alloying followed by sintering (1997) J Alloy Compd, 248, pp. 164-167Selvam, P., Yvon, K., Synthesis of Mg2FeH6, Mg2CoH5 and Mg2NiH4 by High-pressure sintering of the elements (1991) Int J Hydrogen Energ, 16, pp. 615-617Chen, J., Takeshita, H.T., Chartouni, D., Kuriyama, N., Sakai, T., Synthesis and characterization of nanocrystalline Mg2CoH5 obtained by mechanical alloying (2001) J Mater Sci, 36, pp. 5829-5834Zhang, J.X., Cuevas, F., Zaidi, W., Bonnet, J.P., Aymard, L., Bobet, J.L., Highlighting of a single reaction path during reactive Ball milling of Mg and TM by quantitative H2 Gas sorption analysis to form ternary complex hydrides (TM = Fe, Co, Ni) (2011) J Phys Chem C, 115, pp. 4971-4979Asselli, A.A.C., Botta, W.J., Huot, J., Formation reaction of Mg2FeH6: Effect of hydrogen Absorption/desorption kinetics (2013) Mater Res-Ibero-Am J, 16, pp. 1373-1378Asselli, A.A.C., Jorge, A.M., Ishikawa, T.T., Botta, W.J., Mg2FeH6-based nanocomposites with high capacity of hydrogen storage processed by reactive milling (2012) Mater Res-Ibero-Am J, 15, pp. 229-235Asselli, A.A.C., Leiva, D.R., Jorge, A.M., Ishikawa, T.T., Botta, W.J., Synthesis and hydrogen sorption properties of Mg2FeH6-MgH2 nanocomposite prepared by reactive milling (2012) J Alloy Compd, 536, pp. S250-S254Leiva, D.R., Villela, A.C.D., Paiva-Santos, C.D., Fruchart, D., Miraglia, S., Ishikawa, T.T., High-yield direct synthesis of Mg2FeH6 from the elements by reactive milling (2011) Solid State Phenomen, 170, pp. 259-262Leiva, D.R., Zepon, G., Asselli, A.A.C., Fruchart, D., Miraglia, S., Ishikawa, T.T., Mechanochemistry and H-sorption properties of Mg2FeH6-based nanocomposites (2012) Int J Mater Res, 103, pp. 1147-1154Bab, M.A., Mendoza-Zelis, L., A model for the kinetics of mechanically assisted gas-solid reactions (2004) Scr Mater, 50, pp. 99-104Bab, M.A., Mendoza-Zelis, L., Damonte, L.C., Nanocrystalline HfN produced by mechanical milling: Kinetic aspects (2001) Acta Mater, 49, pp. 4205-4213Figueroa, S.J.A., Gibson, D., Mairs, T., Pasternak, S., Newton, M.A., Di Michiel, M., Innovative insights in a plug flow microreactor for operando X-ray studies (2013) J Appl Crystallogr, 46, pp. 1523-1527Varin, R.A., Czujko, T., Chiu, C., Wronski, Z., Particle size effects on the desorption properties of nanostructured magnesium dihydride (MgH2) synthesized by controlled reactive mechanical milling (CRMM) (2006) J Alloy Compd, 424, pp. 356-364Liang, G., Huot, J., Boily, S., Van Neste, A., Schulz, R., Catalytic effect of transition metals on hydrogen sorption in nanocrystalline ball milled MgH2-Tm (Tm = Ti, V, Mn, Fe and Ni) systems (1999) J Alloy Compd, 292, pp. 247-252Gennari, F.C., Castro, F.J., Formation, composition and stability of Mg-Co compounds (2005) J Alloy Compd, 396, pp. 182-192Norek, M., Nielsen, T.K., Polanski, M., Kunce, I., Plocinski, T., Jaroszewicz, L.R., Synthesis and decomposition mechanisms of ternary Mg2CoH5 studied using in situ synchrotron X-ray diffraction (2011) Int J Hydrogen Energ, 36, pp. 10760-10770Fernandez, I.G., Meyer, G.O., Gennari, F.C., Hydriding/dehydriding behavior of Mg2CoH5 produced by reactive mechanical milling (2008) J Alloy Compd, 464, pp. 111-117Fernandez, I.G., Meyer, G.O., Gennari, F.C., Reversible hydrogen storage in Mg2CoH5 prepared by a combined milling-sintering procedure (2007) J Alloy Compd, 446, pp. 106-109Veron, M.G., Condo, A.M., Gennari, F.C., Effective synthesis of Mg2CoH5 by reactive mechanical milling and its hydrogen sorption behavior after cycling (2013) Int J Hydrogen Energ, 38, pp. 973-981Zaluski, L., Zaluska, A., Strom Olsen, J.O., Nanocrystalline metal hydrides (1997) J Alloy Compd, 253, pp. 70-7

Reversible room temperature hydrogen storage in high-entropy alloy TiZrCrMnFeNi

Despite potential of hydride-forming alloys for hydrogen storage, there have been few alloys which can reversibly store hydrogen without heating or activation treatment. In this study, a high-entropy alloy is designed for room temperature hydrogen storage based on three criteria: total valence electron concentration (VEC) of 6.4, single-phase thermodynamic stability (examined by CALPHAD calculations) and AB2H3 hydride formation (A: hydride-forming elements, B: elements without affinity to hydrogen, H: hydrogen). The designated alloy, TiZrCrMnFeNi containing 95 wt% C14 Laves phase, absorbs and desorbs 1.7 wt% of hydrogen (hydrogen-to-metal ratio: 1) at room temperature with a fast kinetics and without activation treatment178387390FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2018/15968-4This work is supported in part by Grants-in-Aid for Scientific Research from the MEXT, Japan (Nos. 16H04539 and 19H05176), in part by a grant from the Brazilian Research Funding Agency FAPESP (Regular Project No. 2018/15968-4), and in part by a grant the Serrapilheira Institute (No. Serra-1709-17362)

Mg-containing multi-principal element alloys for hydrogen storage: A study of the MgTiNbCr_0.5Mn_0.5Ni_0.5 and Mg_0.68TiNbNi_0.55 compositions

Recently, there has been growing interest in multi-principal element alloys for hydrogen storage. However, most of the papers published so far report compositions based only on transition metal elements, which limit the gravimetric storage capacities due to their densities. Since Mg is a low-density element promising for hydrogen storage, the study of Mg-containing multi-principal element compositions is opportune. In the present work, we report for the first time the structural characterization and hydrogen storage properties of the A2B type MgTiNbCr0.5Mn0.5Ni0.5 alloy and its derivative Mg0.68TiNbNi0.55 alloy. These Mg-containing multi-principal element alloys form major BCC phase (W-type, Im3̅ m) and major FCC hydride (MH2 with CaF2-type structure) when synthesized by mechanical alloying (MA) and reactive milling (RM), respectively. Hydrogen is desorbed from both RM samples in two steps, with some overlap, from different hydrides formed during synthesis. The microstructure of the Mg0.68TiNbNi0.55 composition is more homogeneous (less secondary phases), but both alloys present a total gravimetric capacity of around 1.6 wt% H2

Controlled mechanochemical synthesis and hydrogen desorption mechanisms of nanostructured Mg2CoH5

Magnesium complex hydrides are attractive for hydrogen storage applications, mainly due to their high volumetric capacities and to their relatively low cost. In this work, nanocrystalline Mg2CoH5 was synthesized with very high yields (97%) by reactive milling cobalt and magnesium under relatively mild processing conditions (30 bar of H2 pressure and 12 h of milling). The behavior of the milled Mg2CoH5 during heating was studied by a combination of several techniques including DSC, QMS, TGA and in-situ synchrotron XRD. It is shown for the first time that two different mechanisms of hydrogen desorption take place. At low temperatures (up to 325°C), some hydrogen is released by a diffusional mechanism with no change in the crystalline structure of the high temperature γ-Mg2CoH5 phase. At higher temperatures, above 325°C, the γ-Mg2CoH5 phase becomes unstable and the complex hydride decomposes into Mg, Co and H2. This is the first work to report the diffusional hydrogen desorption mechanism for the Mg2CoH5 or any other complex hydride. Furthermore, a complete description of the allotropic β-Mg2CoH5 to γ-Mg2CoH5 phase transition is provided.Fil: Zepon, G.. Universidade Federal do São Carlos; BrasilFil: Leiva, D. R.. Universidade Federal do São Carlos; BrasilFil: Kaufman, M. J.. Colorado School of Mines; Estados UnidosFil: Figueroa, Santiago Jose Alejandro. Centro Nacional de Pesquisa em Energia e Materiais Rua Giuseppe Máximo Scolfaro; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Floriano, R.. Universidade Estadual de Campinas; BrasilFil: Lamas, Diego Germán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Asselli, A. A. C.. Universidade Federal do São Carlos; BrasilFil: Botta, W. J.. Universidade Federal do São Carlos; Brasi