Diapositiva

Invita al Ciclo de Seminarios Internacionales de Investigación 2012, con las siguientes exposiciones (semana 6): “Characterization of chromate conversion coatings for Aerospace use when Hexavalent Chromium is Abstract: Aluminum alloy 2024-T3 has been widely used in aerospace applications due to a good combination of specific weight and mechanical properties. Their desirable mechanical properties result from their heterogeneous microstructure by alloying additions and heat treatment.However, the corrosion performance of the material can be a problem because the alloying elements tend to form various intermetallic particles that make to alloy highly susceptible to localized corrosion. Chromate Conversion coatings (CCC’s) have been employed in the surface finishing process for AA2024 T-3 for their excellent ability to resist localized corrosion and to promote paint adhesion. However, due to the toxic effects of chromium compounds that contain, especially Cr (VI), a significant effort has been extended to substitute this process. TCP coatings(Trivalent Chrome Process) are considered an environmentally friendly replacement for CCC’s, because the TCP bath and the resulting film contain no Cr (VI) species. In the present study, the application of the coatings obtained from a trivalent chromium process on AA2024-T3 has been analyzed through of some characterization techniques as well as the evaluation of its properties of adhesion to the substrate and corrosion Impartida por: I.Q. Jorge Alejandro Torres Flores Fecha de ingreso a la Maestría: Agosto 2011 Director de tesis: Dr. Rafael Colás Ortiz “Synthesis and characterization of bismuth molybdates under hydrothermal conditions in the presence of EDTA and optimization of conditions for the photocatalytic degradation of organic pollutants in aqueous Abstract: In this study was evaluated the photocatalytic activity of Bi2MoO6 hydrothermal oxide synthesized in the presence of EDTA (0.25M, 0.5M and 1M). As a model reaction was followed photocatalytic degradation of indigo carmine at 30 ppm and 20 ppm tetracycline under radiation solar type.The materials were characterized to know their structural properties (XRD), morphology (SEM), optical (UV-Vis) and surface (N2physisorption). Bi2MoO6was successfully synthesized by the hydrothermal method in the presence of EDTA at 4, 8 and 24h of reaction, obtaining significant changes in morphological and textural properties of molybdates, which improved its photocatalytic activity in the degradation reaction of organic contaminants in aqueous medium. Crystalline phase was confirmed by XRD molybdates with 084-0787 JCPDS database. SEM results showed that the morphology and the particle size were strongly influenced by the method of synthesis and addition of EDTA. It was also observed that the concentration of the additive significantly influence the surface properties and morphology of the particles of the molybdate. As a feature of the system, particles were observed in the form of plates at different concentrations of EDTA, with a thickness below 20 nm, and lengths of about 100 nm. Photocatalysts proved busiest those synthesized with 0.25M EDTA, which was developed for the optimization of the reaction conditions using multivariate analysis approach for 2 star variables involved in the photocatalytic process (pH photocatalyst and mass) . The model was validated using the ANOVA test, using the program Modde 7.0.
Impartida por: M.C. Cecilia Sánchez Trinidad Fecha de ingreso al Doctorado: Enero 2011 Director de tesis: Dr. Azael Martínez de la Cruz Viernes 08 de Marzo del 2013, a las 4:00 PM Auditorio René Montante (edificio 6 Planta baja) Invita al Ciclo de Seminarios Internacionales de Investigación 2012, con las siguientes exposiciones (semana 6): “Transparent Nanocomposites with Tunable Refractive Index.” Abstract: Nanocomposites which show visible light transmittance and tunable refractive index based on a polymer matrix and barium titanate (BT) nanoparticles, were prepared. The BT nanoparticles were synthesized by different solution routes. Afterward, the surface of the nanoparticles was modified in order to improve the interaction with the polymer matrix.
Finally, the Nanocomposites were obtained through the embedding of the BT nanoparticles in a polymer solution. The crystal structure of the nanoparticles was analyzed by x-ray diffraction (XRD) and Raman Spectroscopy. Fourier transform infrared spectroscopy (FTIR) results confirmed the surface modification of the nanoparticles. The particle size of the nanoparticles was characterized by dynamic light scattering (DLS) and confirmed via scanning electron microscopy (SEM) images. The optical properties of the nanocomposites were characterized by means of UV/Vis-spectroscopy and ellipsometry.
Impartida por: M.Sc. Nasser Mohamed-Noriega Institute of Inorganic Chemistry I, Technical University of Dresden Viernes 08 de Marzo del 2013, a las 4:00 PM Auditorio René Montante (edificio 6 Planta baja)

Source: http://www.alancastillo.com.mx/app/download/5951853457/Semana+6.pdf?t=1369073035