Diagramas de Frost

En este artículo vamos a aprender qué es un Diagrama de Frost, qué representa, para qué sirve y cuáles son sus principales características. También se explicará cómo construir un diagrama de Frost a partir de los datos contenidos en un diagrama de Latimer.Blasco Tamarit, ME. (2012). Diagramas de Frost. http://hdl.handle.net/10251/1682

Diagramas de Latimer

En este artículo vamos a aprender qué es un Diagrama de Latimer, qué representa, cuál es su utilidad y cuáles son sus principales características. Todo ello lo veremos a través de ejemplos para facilitar el aprendizaje de los conceptos básicos de este documento.Blasco Tamarit, ME. (2011). Diagramas de Latimer. http://hdl.handle.net/10251/1283

Imposed potential measurement to evaluate the pitting corrosion resistance and the galvanic behaviour of a highly alloyed austenitic stainless steel and its weldment in a LiBr solution at temperatures up to 150ºC

Pitting corrosion resistance and galvanic behaviour of Alloy 31, a highly alloyed austenitic stainless steel (UNS N08031), and its weldment were studied in a heavy brine LiBr solution 1080 g/l at different temperatures (75–150 °C) using electrochemical techniques. The Mixed Potential Theory was used to evaluate the galvanic corrosion between the base and welded metals. Cyclic potentiodynamic curves indicate that high temperatures make passivation and repassivation of pits difficult, because the whole passivation range and the repassivation potential values decrease with temperature. The critical pitting transition occurs between 100 and 125 °CWe wish to express our gratitude to Ministerio de Ciencia e Innovacion (CTQ2009-07518/PPQ) for its financial support, to Dr. Helena Elves from Krupp VDM for supplying the materials and to Dr. M. Asuncion Jaime for her translation assistance.Blasco Tamarit, ME.; García García, DM.; García Antón, J. (2011). Imposed potential measurement to evaluate the pitting corrosion resistance and the galvanic behaviour of a highly alloyed austenitic stainless steel and its weldment in a LiBr solution at temperatures up to 150ºC. Corrosion Science. 53(2):784-795. https://doi.org/10.1016/j.corsci.2010.11.013S78479553

Incorporation of the PBL methodology to the subject of Environmental Technology of the Degree in Chemical Engineering at the Alcoy campus

[EN] In the subject of Environmental Technology of the Degree in Chemical Engineering at the UPV on the Alcoy campus, a modification is incorporated in the methodology followed until now. The classes were based on the participatory lecture with resolution of questions and problems in the classroom, and the subsequent evaluation of theoretical tests through tests and open response activities at the end of each didactic unit. This methodology can lead to the student not feeling fully motivated, thus favoring superficial learning of the subject. To ensure that their learning is deep, it is proposed to add in the 2021-2022 academic year a task for each didactic unit in which the student is the protagonist of his own learning and in which he can develop his critical thinking about the problem posed. Once the tasks were carried out by the students, it was observed that a high percentage of students had managed to solve the problems by linking different theoretical concepts explained in class, so the objective of promoting deep learning had been achieved.[ES] En la asignatura de Tecnología del medio ambiente del Grado en Ingeniería Química de la Universitat Politècnica de València en el campus de Alcoy se incorpora una modificación en la metodología seguida hasta ahora. Las clases se basaban en la lección magistral participativa con resolución de cuestiones y problemas en el aula, y la posterior evaluación de pruebas teóricas mediante test y actividades de respuesta abierta al finalizar cada unidad didáctica. Esta metodología puede llevar a que el estudiante no se sienta del todo motivado, favoreciendo así el aprendizaje superficial de la materia. Para conseguir que su aprendizaje sea profundo, se propone añadir en el curso académico 2021-2022 una tarea para cada unidad didáctica en la que el alumno sea el protagonista de su propio aprendizaje y en la cual pueda desarrollar su pensamiento crítico sobre el problema planteado. Una vez realizadas las tareas por los alumnos, se observó que un elevado porcentaje de alumnos habían conseguido solucionar los problemas enlazando distintos conceptos teóricos explicados en clase, por lo que se había alcanzado el objetivo de favorecer el aprendizaje profundo.Mora Gómez, J.; Montañés Sanjuan, MT.; Blasco Tamarit, ME. (2022). Incorporación de la metodología ABP a la asignatura de Tecnología del medio ambiente del Grado en Ingeniería Química en el campus de Alcoy. En In-Red 2022 - VIII Congreso Nacional de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 1007-1016. https://doi.org/10.4995/INRED2022.2022.158711007101

Cavitation corrosion and repassivation kinetics of titanium in a heavy brine LiBr solution evaluated by using electrochemical techniques and Confocal Laser Scanning Microscopy

The cavitation corrosion behaviour of commercially pure Grade 2 titanium in a 992 g/l LiBr solution has been investigated at 25 °C using an ultrasound device. Cavitation was found to have more influence on the anodic branch than on the cathodic branch, shifting the corrosion potential, Ecorr, and the OCP value towards more negative potentials, and increasing the corrosion current density, icorr, by six times. The repassivation kinetics of Grade 2 titanium have also been studied in the 992 g/l LiBr solution, at 25 °C and various applied potentials, using cavitation to damage the electrode surface. The repassivation kinetics have been analysed in terms of the current density flowing from the area damaged by cavitation, and the results were described by the equation i(t) = A·t−n. At potentials within the passive region, the passive film grew according to the high-field ion conduction model in which log i(t) is linearly proportional to 1/q(t). The damage generated during the potentiostatic tests has been quantified by means of Confocal Laser Scanning MicroscopyWe wish express our gratitude to the Ministerio de Ciencia e Innovacion (Project CTQ2009-07518), for the economical support of this research, to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRYM/S/100), and to Dr. M. Asuncion Jaime for her translation assistance.Fernández Domene, RM.; Blasco Tamarit, ME.; García García, DM.; García Antón, J. (2011). Cavitation corrosion and repassivation kinetics of titanium in a heavy brine LiBr solution evaluated by using electrochemical techniques and Confocal Laser Scanning Microscopy. Electrochimica Acta. 58:264-275. https://doi.org/10.1016/j.electacta.2011.09.034S2642755

Effect of potential formation on the electrochemical behaviour of a highly-alloyed austenitic stainless steel in contaminated phosphoric acid at different temperatures

The electrochemical behaviour of the highly alloyed austenitic stainless steel UNS N08031 (Alloy 31) in a contaminated phosphoric acid solution is studied using potentiodynamic curves, EIS and Mott–Shottky. The relative stability of the films formed on Alloy 31 has been studied after a pre-passivated treatment at 0.3, 0.5, 0.8 and 1 VAg/AgCl, potentials within the passive domain. The protection of Alloy 31 was provided by the inner oxide film, while the outer film was more defective. The electronic-semiconducting properties of the passive films have been correlated to corrosion resistance. Passivated Alloy 31 at 0.8 VAg/AgCl showed lower concentration of charge carriers, which beneficially affects the protecting and electronic properties of the passive oxide film.The authors wish to express their gratitude to the MAEC of Spain (PCI Mediterraneo C/8196/07, C/018046/08, D/023608/09 and D/030177/10), to Programa de Apoyo a la Investigacion y Desarrollo de la UPV (PAID-06-09), to the Generalitat Valenciana (GV/2011/093) for the financial support and to Dra. Asuncion Jaime for her translation assistance.Escrivá Cerdán, C.; Blasco Tamarit, ME.; García García, DM.; García Antón, J.; Guenbour, A. (2012). Effect of potential formation on the electrochemical behaviour of a highly-alloyed austenitic stainless steel in contaminated phosphoric acid at different temperatures. Electrochimica Acta. 80:248-256. https://doi.org/10.1016/j.electacta.2012.07.012S2482568

Temperature Effect on the Austenitic Stainless Steel UNS N08031 Used in the Wet Method Phosphoric Acid Production

The influence of temperature (between 20 and 80 degrees C) on the electrochemical behaviour of UNS N08031 (Alloy 31) was evaluated in a contaminated phosphoric acid solution, which simulates the typical concentrations used in the industrial wet process (40 wt.% H3PO4, 2 wt.% H2SO4 and 0.42 wt.% KCl). Alloy 31 electrochemical behaviour was studied by means of polarisation curves and electrochemical impedance spectroscopy. Results demonstrated that temperature decreases the corrosion resistance of Alloy 31.Escrivá Cerdán, C.; Blasco Tamarit, ME.; García García, DM.; García Antón, J.; Guenbour, A. (2013). Temperature Effect on the Austenitic Stainless Steel UNS N08031 Used in the Wet Method Phosphoric Acid Production. Chemical Engineering Transactions. 32:1717-1722. doi:10.3303/CET1332287S171717223

Corrosion Resistance and Galvanic Coupling of UNS N08031 Base Metal, Heat-Affected Zone, and Weld Metal in Phosphoric Acid at Different Temperatures

[EN] Open-circuit potential tests and potentiodynamic anodic polarization curves have been carried out to obtain information about the electrochemical behavior of a highly alloyed austenitic stainless steel (UNS N08031) used as base metal (BM), heat-affected zone (HAZ) region, and weld metal (WM). The weld was performed using the gas tungsten arc welding technique (GTAW) with a nickel-based alloy (UNS N06059) as filler metal. The galvanic corrosion generated by the electrical contact between the base metal, the HAZ, and the weld metal was estimated from the polarization diagrams according to the mixed potential theory. The objective of the present work was to study the effect of the solution temperature on the corrosion resistance of the studied materials. These materials were tested in 5.5 M phosphoric acid (H3PO4) solution at 25°C, 40°C, 60°C, and 80°C. Results demonstrated that materials passivated spontaneously in the studied solution and their corrosion resistance decreased with temperature.We wish to express our gratitude to the Ministerio de Asuntos Exteriores y Cooperación of Spain (PCI Mediterráneo C/8196/07, Ref. C/018046/08, and D/023608/09), to Programa de Apoyo a la Investigación y Desarrollo de la Universidad Politécnica de Valencia (PAID-06-09), and to A. Jaime for her translation assistance.Blasco Tamarit, ME.; García García, DM.; Ibáñez-Ferrándiz, M.; García Antón, J.; Guenbour, A. (2011). Corrosion Resistance and Galvanic Coupling of UNS N08031 Base Metal, Heat-Affected Zone, and Weld Metal in Phosphoric Acid at Different Temperatures. CORROSION. 67(3):350011-3500110. https://doi.org/10.5006/1.3557485S350011350011067

Preparation of electrodes based on WO3 nanostructures for Li-ion batteries [Dataset]

Estos datos han sido empleados en el artículo ya publicado (OPEN ACCES): Journal of the American Ceramic Society 2023;106:2550–2566, https://doi.org/10.1111/jace.18910.The data are related with the preparation of electrodes based on WO3 nanostructures used as anode materials for Li-ion batteries. The nanostructured WO3 thin film was effectively synthesized by an electrochemical procedure. Then, an annealing treatment at 600◦C in air environment for 4 h was carried out. In the second electrode synthesized, a carbon layer was uniformly deposited on WO3 nanostructures to obtain a WO3/C electrode. Finally, WO3/WS2 electrodes were prepared by means of in situ sulfurization of WO3 one-step solid-state synthesis using tungsten trioxide (WO3) and thiourea as precursor material. By using X-ray photoelectron spectroscopy, X-ray diffraction analysis and Raman spectra, the three electrodes have been morphologically characterized. Electrochemical properties were analysed by cyclic voltammogram, galvanostatic charge/discharge cycling, and electrochemical impedance spectroscopy.García Antón, J.; Roselló Márquez, G.; García García, DM.; Cifre Herrando, M.; Blasco Tamarit, ME. (2023). Preparation of electrodes based on WO3 nanostructures for Li-ion batteries [Dataset]. Riunet. https://doi.org/10.4995/Dataset/10251/20025

Characterization and Comparison of WO₃/WO₃-MoO₃ and TiO₂/TiO₂-ZnO Nanostructures for Photoelectrocatalytic Degradation of the Pesticide Imazalil

Tungsten oxide (WO3) and zinc oxide (ZnO) are n-type semiconductors with numerous applications in photocatalysis. The objective of this study was to synthesize and characterize different types of nanostructures (WO3, WO3-Mo, TiO2, and TiO2-ZnO) for a comparison of hybrid and pure nanostructures to use them as a photoanodes for photoelectrocatalytic degradation of emerging contaminants. With the aim of comparing the properties of both samples, field emission scanning electron microscopy (FE-SEM) and confocal laser-Raman spectroscopy were used to study the morphology, composition, and crystallinity, respectively. Electrochemical impedances, Mott-Schottky, and water splitting measurements were performed to compare the photoelectrochemical properties of photoanodes. Finally, the photoelectrocatalytic degradation of the pesticide Imazalil was carried out with the best optimized nanostructure (TiO2-ZnO)