Structural and Magnetic Properties of Amorphous Tb-Dy-Fe-Co Thin Films

This paper reports the effect of film thickness (50, 200, 400 and 800 nm) on the structural and magnetic properties of amorphous Tb-Dy-Fe-Co alloy thin films. All the films are found to exhibit perpendicular magnetic anisotropy (PMA) irrespective of the film thickness. The PMA is found to decrease with increase in film thickness due to the decrease in the magnetic texture and anisotropy energy. While the coercivity deduced from the out-of-plane magnetization curve increases with increasing film thickness, the in-plane coercivity exhibits weak thickness dependence. The irreversibility point in the thermo-magnetic curves obtained from field-cooled and zero-field-cooled measurements along the out-of-plane direction is found to shift towards higher temperature compared to the measurements in in-plane directions, indicating the presence of strong PMA.

NH3 adsorption on PtM (Fe, Co, Ni) surfaces: Cooperating effects of charge transfer, magnetic ordering and lattice strain

Adsorption of a molecule or group with an atom which is less electronegative than oxygen (0) and directly interacting with the surface is very relevant to development of PtM (M = 3d-transition metal) catalysts with high activity. Here, we present theoretical analysis of the adsorption of NH3 molecule (N being less electronegative than 0) on (111) surfaces of PtM (Fe, Co, Ni) alloys using the first principles density functional approach. We find that, while NH3-Pt interaction is stronger than that of NH3 with the elemental M-surfaces, it is weaker than the strength of interaction of NH3 with M-site on the surface of PtM alloy. (C) 2016 Published by Elsevier B.V.

Na2M2(SO4)(3) (M = Fe, Mn, Co and Ni): towards high-voltage sodium battery applications

Sodium-ion-based batteries have evolved as excellent alternatives to their lithium-ion-based counterparts due to the abundance, uniform geographical distribution and low price of Na resources. In the pursuit of sodium chemistry, recently the alluaudite framework Na2M2(SO4)(3) has been unveiled as a high-voltage sodium insertion system. In this context, the framework of density functional theory has been applied to systematically investigate the crystal structure evolution, density of states and charge transfer with sodium ions insertion, and the corresponding average redox potential, for Na2M2(SO4)(3) (M = Fe, Mn, Co and Ni). It is shown that full removal of sodium atoms from the Fe-based device is not a favorable process due to the 8% volume shrinkage. The imaginary frequencies obtained in the phonon dispersion also reflect this instability and the possible phase transition. This high volume change has not been observed in the cases of the Co- and Ni-based compounds. This is because the redox reaction assumes a different mechanism for each of the compounds investigated. For the polyanion with Fe, the removal of sodium ions induces a charge reorganization at the Fe centers. For the Mn case, the redox process induces a charge reorganization of the Mn centers with a small participation of the oxygen atoms. The Co and Ni compounds present a distinct trend with the redox reaction occurring with a strong participation of the oxygen sublattice, resulting in a very small volume change upon desodiation. Moreover, the average deintercalation potential for each of the compounds has been computed. The implications of our findings have been discussed both from the scientific perspective and in terms of technological aspects.

Anomalous Thermal Stability of Nd-Fe-Co-Al Bulk Metallic Glass

The thermal stability of Nd60Fe20Co10Al10 bulk metallic glass (BMG) has been studied by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), isochronal dilatation and compression tests. The results show that the glass transition of the BMG takes place quite gradually between about 460 and 650 K at a heating rate of 0.17 K/s. Several transformation processes are observed during continuous heating with the first crystallization process beginning at about 460 K, while massive crystallization takes place near the solidus temperature of the alloy. The positive heat of mixing between the two major constituents, Nd and Fe, and, consequently, a highly inhomogeneous composition of the attained amorphous phase are responsible for the anomalous thermal stability in this system. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

Nonequilibrium microstructures and their evolution in a Fe-Cr-W-Ni-C laser clad coating

The laser-solidified microstructural and compositional characterization and phase evolution during tempering at 963 K were investigated using an analytical transmission electron microscope with energy dispersive X-ray analysis. The cladded alloy, a powder mixture of Fe, Cr, W, Ni, and C with a weight ratio of 10:5:1:1:1, was processed with a 3 kW continuous wave CO2 laser. The processing parameters were 16 mm/s beam scanning speed, 3 mm beam diameter. 2 kW laser power, and 0.3 g/s feed rate. The coating was metallurgically bonded to the substrate, with a maximum thickness of 730 mu m, a microhardness of about 860 Hv and a volumetric dilution ratio of about 6%. Microanalyses revealed that the cladded coating possessed the hypoeutectic microstructure comprising the primary dendritic gamma-austenite and interdendritic eutectic consisted of gamma-austenite and M7C3 carbide. The gamma-austenite was a non-equilibrium phase with extended solid solution of alloying elements and a great deal of defect structures, i.e. a high density of dislocations, twins, and stacking faults existed in gamma phase. During high temperature aging, in situ carbide transformation occurred of M7C3 to M23C6 and M6C. The precipitation of M23C6, MC and M2C carbides from austenite was also observed.

铁基抗高温磨损激光熔覆涂层强韧设计和研究II:Fe-Cr-C-W-Ni激光熔覆层的微观组织及性能

本文以对热工模具进行失效分析的基础上，利用激光熔覆技术，在５ＣｒＭｎＭｏ基础上设计并制备强韧兼备的抗高温磨损涂层。

Modeling Nonlinear Peeling of Ductile Thin Films-Critical Assessment of Analytical Bending Models Using FE Simulations

Three analytical double-parameter criteria based on a bending model and a two-dimensional finite element analysis model are presented for the modeling of ductile thin film undergoing a nonlinear peeling process. The bending model is based on different governing parameters: (1) the interfacial fracture toughness and the separation strength, (2) the interfacial fracture toughness and the crack tip slope angle, and (3) the interfacial fracture toughness and the critical Mises effective strain of the delaminated thin film at the crack tip. Thin film nonlinear peeling under steady-state condition is solved with the different governing parameters. In addition, the peeling test problem is simulated by using the elastic-plastic finite element analysis model. A critical assessment of the three analytical bending models is made by comparison of the bending model solutions with the finite element analysis model solutions. Furthermore, through analyses and comparisons for solutions based on both the bending model and the finite element analysis model, some connections between the bending model and the finite element analysis model are developed. Moreover, in the present research, the effect of different selections for cohesive zone shape on the ductile film peeling solutions is discussed.

Temperature Dependence of the Tribological Properties of Laser Re-Melted Al-Cu-Fe Quasicrystalline Plasma Sprayed Coatings

The aim of this study was to investigate the effect of temperature on tribological properties of plasma-sprayed Al-Cu-Fe quasicrystal (QC) coating after laser re-melting treatment. The laser treatment resulted in a more uniform, denser and harder microstructure than that of the as-sprayed coatings. Tribological experiments on the coatings were conducted under reciprocating motion at high frequency in the temperature range from 25 to 650 degreesC. Remarkable influence of temperature on the friction behavior of the coating was recorded and analyzed. Microstructural analysis indicated that the wear mechanisms of the re-melted QC coatings changed from abrasive wear at room temperature, to adhesive wear at 400 degreesC and severe adhesive wear at 650 degreesC owing to the material transfer of the counterpart ball. It was also observed that the ratio of the icosahedral (i)-phase to beta-Al-50(Fe,CU)(50) phase in the coating was higher after test at 400 'C than that at 650 'C. The variation of the ratio UP of coating and of the property of the counterpart ball and coating with the temperature are the two main factors influencing the wear mechanisms and value of the friction coefficient.

Santo Tomás y las razones de la fe

Pocos días antes del cierre del Concilio Vaticano II, el papa Pablo VI expresaba a los miembros de la Academia Santo Tomás de Aquino lo siguiente: …vuestros estudios pueden contribuir a disipar el menosprecio de un cierto número de creyentes que hoy son tentados por un renaciente fideísmo. Al no atribuir valor más que al pensamiento de tipo científico, y desconfiando de las certezas propias de la sabiduría filosófica, son llevados a fundar sobre una opción de la voluntad su adhesión al orden de las verdades metafísicas. Frente a esta abdicación de la inteligencia, que tiende a arruinar la doctrina tradicional de los preámbulos de la fe, vuestros trabajos deben evocar el valor indispensable de la razón natural, solemnemente afirmado por el Concilio Vaticano I (Dz-Sch. 3004, 3009, 3015 y 3026), en conformidad con la enseñanza constante de la Iglesia, de la que Santo Tomás de Aquino es uno de los testimonios más autorizados y eminentes...

Hermeneútica jurídica y comunión en la fe católica. (Apostillas al discurso de Benedicto XVI a la Rota romana, el 21 de enero de 2012)

La convocatoria a recorrer un “Año de la fe” permitió a Benedicto XVI centrar su alocución de 2012 a la Rota romana en ese próximo acontecimiento eclesial. La extrema importancia que el Pontífice atribuye a su llamada a renovar la fe católica se puso de manifiesto en las palabras que dirigiera unos días más tarde a la plenaria de la Congregación para la Doctrina de la Fe...

Different methods of manufacturing FE-based oxygen carrier particles for reforming via chemical looping, and their effect on performance

Chemical looping combustion (CLC) is a means of combusting carbonaceous fuels, which inherently separates the greenhouse gas carbon dioxide from the remaining combustion products, and has the potential to be used for the production of high-purity hydrogen. Iron-based oxygen carriers for CLC have been subject to considerable work; however, there are issues regarding the lifespan of iron-based oxygen carriers over repeated cycles. In this work, haematite (Fe2O3) was reduced in an N2+CO+CO2 mixture within a fluidised bed at 850°C, and oxidised back to magnetite (Fe3O4) in a H2O+N2 mixture, with the subsequent yield of hydrogen during oxidation being of interest. Subsequent cycles started from Fe3O4 and two transition regimes were studied; Fe3O4↔Fe0.947O and Fe 3O4↔Fe. Particles were produced by mechanical mixing and co-precipitation. In the case of co-precipitated particles, Al was added such that the ratio of Fe:Al by weight was 9:1, and the final pH of the particles during precipitation was investigated for its subsequent effect on reactivity. This paper shows that co-precipitated particles containing additives such as Al may be able to achieve consistently high H2 yields when cycling between Fe3O4 and Fe, and that these yields are a function of the ratio of [CO2] to [CO] during reduction, where thermodynamic arguments suggest that the yield should be independent of this ratio. A striking feature with our materials was that particles made by mechanical mixing performed much better than those made by co-precipitation when cycling between Fe3O4 and Fe0.947O, but much worse than co-precipitated particles when cycling between Fe3O 4 and Fe.

Creemos porque amamos : la estructura interna del acto de fe en John Henry Newman

El autor nos introduce en la cuestión de los motivos racionales de la fe. Las operaciones llevadas a cabo por la inteligencia y la voluntad en el acto de creer, constituyen el fundamento por el cual la Verdad revelada entabla históricamente el diálogo con el hombre. El tema se halla en el centro de la experiencia religiosa y de la reflexión teológica de Newman, y ha significado un aporte indiscutible a la teología contemporánea.

Entrevista a Michael Eigen : el hálito de la fe

"El Dr. Michael Eigen es psicoterapeuta, senior member y analista didáctico de la National Psychological Association for Psychoanalysis. Ha publicado más de una veintena de libros. Es reconocido mundialmente por su voz innovadora, a la vez trascendente y encarnada, profundamente comprometida con las problemáticas actuales. Con 79 años, es profesor en el programa de posdoctorado de psicoterapia y psicoanálisis de la universidad de Nueva York. Supervisa y ejerce la clínica en un pequeño consultorio frente al Central Park, donde a su vez dicta seminarios sobre Bion, Winnicott y Lacan hace más de 35 años. Ha sido editor del Psychoanalitic Review y ha desempeñado cargos en diversas instituciones. Su última publicación, Faith, es una refinada amalgama entre la experiencia y la novedad, entre lo conceptual y lo poético..."