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Your search keyword '"Cáceres-Díaz, L."' showing total 7 results
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7 results on '"Cáceres-Díaz, L."'

1. Effect of pre-oxidation treatments on the structural, microstructural, and chemical properties of (Ni,Pt)Al systems

Author

Garcia-Herrera, J. E., Espinosa-Arbelaez, D. G., Caceres-Diaz, L. A., Mondragon-Rodriguez, G. C., Ruiz-Luna, H., Gonzalez-Hernandez, J., Munoz-Saldana, J., and Alvarado-Orozco, J. M.

Subjects
Condensed Matter - Materials Science
Abstract

The effect of isothermal pre-oxidation treatments on the \b{eta}-(Ni,Pt)Al + Ren\'e N5 system degradation is here reported. The oxidation treatments were carried out from 900 (mostly {\theta}-Al2O3 growing conditions) to 1200{\deg}C (mainly {\alpha}-Al2O3 growing conditions) for 5 h, under a purified Ar-stream with a fixed pO2= 1 x 10-5 atm. Results are discussed based on the correlation between the structural, microstructural and chemical properties of the \b{eta}-(Ni,Pt)Al BC showing that pre-oxidation parameters have an important effect on the multi-elemental counter diffusion phenomena along BC. For instance, a significant BC+IDZ thickness increase of 55% at 1200 {\deg}C was observed with respect to as-received sample just after 5 h of oxidation resulting in a severe BC degradation., Comment: 18 pages, 7 Figures

Published
2018

2. Plasma-assisted nitriding of M2 tool steel: An experimental and theoretical approach

Author

Gonzalez-Carmona, J. M., Mondragon-Rodriguez, G. C., Galvan-Chaire, J. E., Gomez-Ovalle, A. E., Caceres-Diaz, L. A., Gonzalez-Hernandez, J., and Alvarado-Orozco, J. M.

Subjects
Condensed Matter - Materials Science
Abstract

Present work was aimed to investigate the effect of nitriding time; 1, 1.5, 2.5 & 3.5 h, on surface characteristics & mechanical properties (surface nano-hardness, hardness Vickers, and adhesion) of AISI M2 tool steel. Mechanically effective compound (4 to 17.6 um) and diffusion layers (50.8 to 82.4 um) were obtained. Plasma nitriding considerably improved Surface engineering has been recognized as a family of technologies used to modify or improve the surface properties of a substrate. Nano-hardness, E-moduli and resistance to scratch of AISI M2 steel. Surface properties enhancement was associated to two harmonious effects at the nano-scale resulted by (a) stable nitride phases formation such as: gamma-Fe4N, epsilon-Fe2,3N, and (b) no brittle nitride networks and no critical decarburization of the steel upon nitriding. Thermodynamic calculations are in agreement with the experimental findings., Comment: 9 Figures, 4 Tables, 16 pages

Published
2018

5. Diseño y construcción de un contador proporcional de flujo de gas con aplicación en espectroscopia Mössbauer.

Author

Marín Ramírez, J. M., Cáceres Díaz, L. A., Rojas-Martínez, Y., Osorio, J. A., Medina Barreto, M. H., and Cruz-Muñoz, B.

Abstract

The design, construction and operation parameters of a gas flow proportional counter are presented in order to implement the integral conversion electron mössbauer spectroscopy technique (ICEMS). The detector works with the support of a multi-channel detection system and a source of highenergy radiation of 57Co. A constant gas flow of a mixture of 5% CH4 in He was used as a multiplier gas, which increased the signal intensity, and protected the sample's surface of electric shocks. An internal filter for low energy X-rays was considered during the design to achieve a lower background noise and optimize the volume of gas consumed. With this built-in ICEMS detector it is feasible to characterize efficiently the magnetic properties and oxidation states (hyperfine interactions) of both bulk materials and thin films. The calibration of the device was performed by using an iron sample synthesized by powder metallurgy. It was successfully identified the presence of a distinctive sextet of the a-Fe phase with a hyperfine field of 330 kOe and an isomer shift of 0.312 mm / s. The great usefulness of the equipment was verified by solving the magnetic hyperfine interactions of the Mössbauer spectrum associated to a commercial stainless-steel washer. [ABSTRACT FROM AUTHOR]

Published
2018

7. Efectos de la Presión de Oxigeno y la Temperatura del Sustrato Sobre las Propiedades Eléctricas y Magnéticas en Películas Delgadas de Manganitas Crecidas por Ablación Láser.

Author

Cáceres Díaz, L. A., Pérez, F. A., Cruz, B., Granada, D., Riascos, H., Caicedo, J. C., Lopera, W., and Perez, G. A.

Subjects
*THIN films, *LANTHANUM compounds, *MANGANESE compounds, *PULSED laser deposition, *STRONTIUM compounds
Abstract

We studied the magnetic properties of thin films of La2/3Ca1/3MnO3 grown by pulsed laser deposition on single crystal of SrTiO3 (001) substrate. All samples exhibited low roughness and good cristalinity as indicated from X-ray difractometry and topographical perfilometry, respectively. We investigated the plume of laser ablation during the growth by means of the optical emission spectroscopy; it founded the characteristic atomic peaks of La, Ca, MnO y O. The magnetic properties of magnetic films were analized by means of the dependence of magnetization with temperature and magnetic field and it showed a strong dependence of Curie temperature. [ABSTRACT FROM AUTHOR]

Published
2008

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