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Microstructural evaluation and nanohardness of an AlCoCuCrFeNiTi high-entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 634-641页

作者： C.D.Gómez-Esparza R.Peréz-Bustamante J.M.Alvarado-Orozco J.Mu?oz-Salda?a R.Martínez-Sánchez J.M.Olivares-Ramírez A.Duarte-Moller Centro de Investigación en materiales Avanzados (CIMAV) Laboratorio Nacional de Nanotecnología CONACYT-Corporación Mexicana de Investigación en materiales S.A.de C.V.(COMIMSA) Centro de Ingeniería y desarrollo Industrial Querétaro Campus Centro de Investigación y de estudios Avanzados del IPN Unidad Querétaro Universidad Tecnológica de San Juan del Río Escuela de Ingeniería Civil Industrialy Mecánica Universidad De La Salle Bajío

An AlCoCuCrFeNiTi high-entropy alloy(HEA) was prepared by mechanical alloying and sintering to study the effect of Ti addition to the widely studied AlCoCuCrFeNi system. The structural and microstructural characteristics were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The formation of four micrometric phases was detected: a Cu-rich phase with a face-centered cubic(fcc) structure, a body-centered cubic(bcc) solid solution with Cu-rich plate-like precipitates(fcc), an ordered bcc phase, and a tetragonal structure. The XRD patterns corroborate the presence of a mixture of bcc-, fcc-, and tetragonal-structured phases. The Vickers hardness of the alloy under study was more than twice that of the AlCoCuCrFeNi alloy. Nanoindentation tests were performed to evaluate the mechanical response of the individual phases to elucidate the relationship between chemical composition, crystal structure, and mechanical performance of the multiphase microstructure of the AlCoCuCrFeNiTi HEA.

关键词： high-entropy alloys mechanical alloying microstructure nanoindentation

Low-Cost and Biodegradable Thermoelectric devices Based on van der Waals Semiconductors on Paper Substrates

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Energy & Environmental Materials 2024年第1期7卷 201-206页

作者： Gulsum Ersu Carmen Munuera Federico J.Mompean Daniel Vaquero Jorge Quereda João Elias F.S.Rodrigues Jose A.Alonso Eduardo Flores Jose R.Ares Isabel J.Ferrer Abdullah M.Al-Enizi Ayman Nafady Sruthi Kuriakose Joshua O.Island Andres Castellanos-Gomez Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMM-CSIC)Madrid E-28049Spain Nanotechnology Group USAL-NanolabUnivesidad de SalamancaSalamanca Junta de Castilla y León 37007Spain GISC Departamento de Física de MaterialesUniversidad Complutense de MadridMadrid E-28040Spain departamento de Física Aplicada Centro de Investigación y Estudios AvanzadosMérida 97310Mexico MIRE Group Departamento de Física de MaterialesUniversidad Autónoma de MadridMadrid E-28049Spain Instituto Nicolás Cabrera Universidad Autónoma de MadridMadrid E-28049Spain department of Chemistry College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia department of Physics and Astronomy University of Nevada Las VegasLas Vegas NV 89154USA

We present a method to fabricate handcrafted thermoelectric devices on standard office paper *** devices are based on thin films of WS_(2),Te,and BP(P-type semiconductors)and TiS_(3)and TiS_(2)(N-type semiconductors),deposited by simply rubbing powder of these materials against *** thermoelectric properties of these semiconducting films revealed maximum Seebeck coefficients of(+1.32±0.27)mV K^(-1)and(-0.82±0.15)mV K^(-1)for WS_(2)and TiS_(3),***,Peltier elements were fabricated by interconnecting the P-and N-type films with graphite electrodes.A thermopower value up to 6.11 mV K^(-1)was obtained when the Peltier element were constructed with three *** findings of this work show proof-of-concept devices to illustrate the potential application of semiconducting van der Waals materials in future thermoelectric power generation as well as temperature sensing for low-cost disposable electronic devices.

关键词： paper-based electronics Seebeck effect semiconductors thermoelectrics van der Waals materials

Imaging resolution of biocatalytic activity using nanoscale scanning electrochemical microscopy

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Nano Research 2018年第8期11卷 4232-4244页

作者： Jase M .Abad Alvaro Y. Tesio EmUiano Martinez-Perinan Felix Pariente Encamacion Lorenzo departamento de Qufmica Analftica y Andlisis Instrumental Universidad Aut6noma de Madrid Cantoblanco 28049 Madrid Spain Centro de Investigaci6n y desarrollo en materiales Avanzados y Almacenamiento de Energfa de Jujuy-CIDMEJu (CONICET-UniversidadNacional de Jujuy) Centro de Desarrollo Tecnol6gico General Savio Av. Martijena s/n 4612-Palpald Jujuy Argentina Instituto Madrileno de estudios Avanzados en Nanociencia (IMdeA-Nanociencia) Campus UAM Cantoblanco 28049 Madrid Spain

Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the greatest challenge has been the scaling down to the nanoscale for fabrication and the use of nanometer-sized tips. Here, Pt nanoelectrodes with nanometer electroactive area were fabricated and employed for imaging a distribution of gold nanoparticles （AuNPs） and bioelectrocatalytic activity of a redox-active enzyme immobilized on gold surfaces.

关键词： scanning electrochemicalmicroscopy gold nanoparticle redox enzyme nanoelectrode lactate oxidase

Pyrenetetraone-based covalent organic framework as an effective electrocatalyst for oxygen reduction reaction

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Nano Research 2022年第5期15卷 3907-3912页

作者： Paloma Garcia-Arroyo Emiliano Martinez-Perinan Jorge J.Cabrera-Trujillo Elena Salagre Enrique G.Michel Jose I.Martinez Encarnacion Lorenzo Jose L.Segura departamento de Quimica Organica I Facultad de CC.QuimicasUniversidad Complutense de Madrid28040 MadridSpain departamento de Quimica Analitica y Analisis Instrumental Facultad de CienciasUniversidad Autónoma de Madrid28049 MadridSpain departamento de Fisica de la Materia Condensada Universidad Autónoma de Madrid28049 MadridSpain Condensed Matter Physics Center(IFIMAC) Universidad Autónoma de Madrid28049 MadridSpain departamento de Nanoestructuras SuperficiesRecubrimientos y Astrofisica MolecularInstituto de Ciencia de Materiales de Madrid(ICMMCSIC)28049 MadridSpain Instituto Madrileno de estudios Avanzados en Nanociencia(IMdeA-Nanociencia) 28049 MadridSpain Institute for Advanced Research in Chemical Sciences(IAdChem) Universidad Autonoma de Madrid28049 MadridSpain

A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cathode materials with multiple redox sites as an efficient electrocatalyst for the oxygen reduction reaction(ORR).In contrast with most of the previously reported COFs as electrocatalysts for the ORR,the electrocatalytic application of this material towards ORR has been investigated without adding any metal or conductive supporting material and avoiding any additional carbonization ***,the electrochemical properties of the COF material have been compared with two analogue amorphous frameworks with similar chemical composition,which points out the important role of the enhanced crystallinity and porosity of the COF network in its superior performance as an electrocatalyst towards ORR.

关键词： electrocatalysis oxygen reduction reaction metal free pyrenetetraone covalent organic framework

Effects of Silicon Nanoparticles on the Transient Liquid Phase Bonding of 304 Stainless Steel

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Journal of Materials Science & Technology 2014年第3期30卷 259-262页

作者： H.M.Hdz-García A.I.Martinez R.Mu?oz-Arroyo J.L.Acevedo-Dávila F.García-Vázquez F.A.Reyes-Valdes Corporación Mexicana de Investigación en materiales S.A.de C.V. Ciencia y Tecnología No.790 Fracc.Saltillo 400 Saltillo Coah.CP.25290 Mexico Centro de Investigación y de estudios Avanzados del IPN Carr.Mty-Saltillo km.13 Ramos Arizpe Coah.CP.25900 Mexico

Transient liquid phase （TLP） bonding of 304 stainless steel with nickel based filler metal, BNi-9, was performed to study the influence of silicon nanoparticles （NPs） on the mechanical and structural properties of the bonding area. It was found that silicon NPs act as a melting point depressant in the brazing process; the formation of silicon TLP induces the dissolution of elements of the metal filler and promotes a uniform distribution in the bonding area. Silicon NPs induce the development of smaller eutectic structures in the melting zone; it has been related to microhardness measurements, which are lower when the silicon NPs are used in the brazing process.

关键词： Brazing Nanoparticles Silicon Stainless steel

Biocompatibility and electrochemical evaluation of ZrO_(2) thin films deposited by reactive magnetron sputtering on MgZnCa alloy

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Journal of Magnesium and Alloys 2021年第6期9卷 2019-2038页

作者： Benjamín Millán-Ramos Daniela Morquecho-Marín Phaedra Silva-Bermudez David Ramírez-Ortega Osmary depablos-Rivera Julieta García-López Mariana Fernández-Lizárraga JoséVictoria-Hernández Dietmar Letzig Argelia Almaguer-Flores Sandra E.Rodil Instituto de Investigaciones en materiales Universidad Nacional Autónoma de MéxicoCDMX 04510Mexico Posgrado en Ciencia e Ingeniería de materiales Universidad Nacional Autónoma de MéxicoCDMX 04510Mexico Unidad de Ingeniería de Tejidos Terapia Celular y Medicina RegenerativaInstituto Nacional de Rehabilitación Luis Guillermo IbarraCDMX 14389Mexico Posgrado en Ciencias Médicas Odontológicas y de la SaludUniversidad Nacional Autónoma de MéxicoCDMX 04510Mexico Instituto de Ciencias Aplicadas y Tecnologia Universidad Nacional Autónoma de MéxicoCDMX 04510Mexico Posgrado de Doctorado en Ciencias en Biomedicina y Biotecnología Molecular Escuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalCDMX 11340Mexico Institute of Material and Process design Helmholtz-Zentrum GeesthachtMax-Planck-Strasse 1Geesthacht 21502Germany Magnesium Innovation Centre MagIC Helmholtz-Zentrum GeesthachtMax-Planck-Strasse 1Geesthacht 21502Germany Laboratorio de Biointerfases Facultad de OdontologíaDivisión de Estudios de Posgrado e InvestigaciónUniversidad Nacional Autónoma de MéxicoCDMX 04510Mexico

Biodegradable magnesium alloys are promising candidates for temporary fracture fixation devices in orthopedics;nevertheless,its fast degradation rate at the initial stage after implantation remains as one of the main challenges to be ***_(2)-based coatings to reduce the degradation rate of the Mg-implants are an attractive solution since they show high biocompatibility and *** this work,the degradation,cytotoxicity,and antibacterial performance of ZrO_(2)thin films deposited by magnetron sputtering on a Mg-Zn-Ca alloy was ***-term degradation of ZrO_(2)-coated and uncoated samples was assessed considering electrochemical techniques and H_(2)evolution(gas chromatography).Additionally,long term degradation was assessed by mass-loss *** results showed that a 380 nm ZrO_(2)coating reduces the degradation rate and H_(2)evolution of the alloy during the initial 3 days after immersion but allows the degradation of the bare alloy for the *** ZrO_(2)coating does not compromise the biocompatibility of the alloy and permits better cell adhesion and proliferation of mesenchymal stem cells directly on its surface,in comparison to the bare ***,the ZrO_(2)coating prevents the adhesion and biofilm formation of ***.

关键词： Zirconium dioxide Magnetron sputtering Short-term degradation H_(2)evolution

Surface Properties of Fe_4N Compounds Layer on AISI 4340 Steel Modified by Pulsed Plasma Nitriding

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Journal of Materials Science & Technology 2013年第3期29卷 287-290页

作者： J.C.Díaz-Guillén G.Vargas-Gutiérrez E.E.Granda-Gutiérrez J.S.Zamarripa-Pia S.I.Pérez-Aguilar J.Candelas-Ramírez L.lvarez-Contreras Centro de Investigacin en materiales Avanzados S.C.Miguel de Cervantes 120Complejo Industrial ChihuahuaC.P.31109 ChihuahuaChihuahuaMexico Corporacin Mexicana de Investigacin en materiales S.A.de C.V.Ciencia y Tecnología No 790Fracc.Saltillo 400C.P.25290 SaltilloCoahuilaMexico Centro de Investigacin y estudios Avanzados del IPN Unidad SaltilloCarretera Saltillo Monterrey km 13Apdo.Postal 663C.P.25000 SaltilloCoahuilaMexico

In this work, the effect of nitriding current density on hardness, crystalline phase composition, layer thickness and corrosion rate of AlSl 4340 steel has been studied. X-ray diffraction analysis shows that thin layers formed during nitriding process are constituted of 7-Fe4N for samples processed between 1 and 2.5 mA/cm2. Thickness of nitrided layer increases proportionally to current density （0 μm for 0.5 mA/cm2 to 15 pm for 2.5 mA/cm2）. Plasma nitriding increased the surface hardness from 300 HV50g for untreated sample, to around 800HV5og for nitrided samples at 1 mA/cm2. While the untreated samples exhibited a corrosion rate of 0.153 mm per year, the corrosion performance was improved up to 0.03 mm per year at current densities above 1 mA/cm2, which is about one fifth of the corrosion rate of the untreated sample.

关键词： Plasma nitriding Current density Hardness Corrosion

Electric,magnetic and microstructural features of the La_(2)CoFeO_(6) lanthanide ferrocobaltite obtained by the modified Pechini route

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Journal of Advanced Dielectrics 2021年第3期11卷 16-25页

作者： J.A.Jaramillo Palacio K.A.Munoz Pulido J.Arbey Rodríguez D.A.Landínez Téllez J.Roa-Rojas grupo de Física de Nuevos materiales Departamento de Física Universidad Nacional de ColombiaBogotáDCColombia Laboratório de Magnetismo e Materiais Magnéticos departamento de Física Universidade Federal de Santa Maria Rio Grande do Sul Brazil grupo de estudios de materiales Departamento de Física Universidad Nacional de ColombiaBogotáDCColombia

In the search for new materials with applicable magnetic properties in spintronic devices,the aim of this work is to report the synthesis of the lanthanide ferrocobaltite La_(2)CoFeO_(6) using the modified Pechini route;the experimental study of structural,morphological and magnetic properties,and the analysis of the electronic structure and bands are obtained in the framework of the density Functional *** refinement of experimental X-ray diffraction patterns revealed the crystallization of this oxide material in a perovskite-like monoclinic structure,space group P2_(1)/n(#14).Scanning electron microscopy and atomic force microscopy images revealed that the surface morphology is essentially polycrystalline,with mean grain sizes between 177 and 188 *** dispersive X-ray spectroscopy suggests that the material obtained contains La,Fe,Co and O in the stoichiometric proportions expected by up to 98%.The magnetic susceptibility curves as a function of temperature indicated that the material is ordered ferromagnetically,showing strong irreversibility effects due to the disorder of the Fe and Co cations in the three crystallographic directions of the structure and to the strong distortions in the FeO_(6) and CoO_(6) *** hysteresis curves confirmed the ferromagnetic character of the material for all temperatures evaluated,up to room temperature.I-V response curves revealed a semiconductor-like behavior with a figure of merit exponent 1.53 of the varistor *** ferromagnetic semiconductor behavior suggests the potential applicability of the material in spintronic technological devices.

关键词： Double perovskite Pechini method crystalline structure ferromagnetic response semiconductor behavior

Non-linear modeling of kinetic and equilibrium data for the adsorption of hexavalent chromium by carbon nanomaterials:Dimension and functionalization

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Chinese Journal of Chemical Engineering 2019年第4期27卷 912-919页

作者： Miguel de la Luz-Asunción Eduardo E.Pérez-Ramírez Ana L.Martínez-Hernández Victor M.Castano Víctor Sánchez-Mendieta Carlos Velasco-Santos Facultad de Quimica Universidad Autonoma del Estado de Mexico Km. 12 de la carretera Toluca-Atlacomulco C.P. 50200 San Cayetano Toluca Estado de Mexico Mexico Tecnologico Nacional de Mexico-Instituto Tecnologico de Queretaro Division de Estudios de Posgrado e Investigacion Av. Tecnologico s/n esq. GraL Mariano Escobedo Col. Centro Historico C.P. 76000 Santiago de Queretaro Queretaro Mexico Centro de Fisica Aplicada y Tecnologia Avanzada Universidad Nacional Autonoma de Mexico Boulevard Juriquilla 3001 Queretaro 76230 Mexico

The adsorption capacities for the removal of hexavalent chromium from aqueous solutions by six carbon nanomaterials have been evaluated. Single-walled and multi-walled carbon nanotubes as received and after oxidation treatment, graphene oxide and reduced graphene oxide are the materials with different dimension and functionalization compared in this research. Carbon nanotubes have been modified using hydrogen peroxide as oxidizing agent under microwave radiation. The oxidation treatment on carbon nanotubes has a positive effect increasing the adsorbent–adsorbate interaction. Rate-controlling mechanisms and equilibrium data are analyzed using non-linear models. Non-linear method is proposed as the most suitable method for determining the kinetic and equilibrium parameters. The values of adsorption energy(E) obtained from the Dubinin–Radushkevich isotherm,have been found around 0.371 and 0.870 k J·mol-1, indicating physical adsorption. Therefore, the pseudo-second order model represents better the kinetic experimental data. The results show that the Langmuir isotherm provides a slightly better fit to the experimental data compared with the Freundlich isotherm, indicating homogeneous distribution of active sites on carbon nanomaterials and monolayer adsorption. The separation factors RLare found in the range of 0–1, suggesting that the adsorption process is suitable for all adsorbents. The mechanisms for hexavalent chromium removal have been proposed as electrostatic interactions and hydrogen bonding.

关键词： Carbon nanotubes Graphene Adsorption Hexavalent chromium Kinetic