30 años impulsando la electroquímica en México

Libro de memorias sobre electroquímica, celebrando el 30 aniversario de la Sociedad Mexicana de Electroquímica. Este libro se ha estructurado en dos grandes secciones, en una se hace una reseña de la Sociedad, donde se menciona el origen, la formalización y misión de la misma; indicando quienes han sido sus presidentes, quienes conforman el consejo consultivo, lugares donde se han llevado los 30 Congresos de la SMEQ. Y la segunda sección se ha dividido en 8 capítulos, donde se cubren las temáticas de cada una de las divisiones. Todos estos capítulos constituyen los tópicos de interés sobre los que se han centrado los diversos trabajos de los miembros de la Sociedad. Los capítulos son expuestos por un coordinador, que de acuerdo a su trayectoria y liderazgo en el área ha recopilado las actividades y logros relevantes del área de interés

Diseño de una celda electrolítica para aplicación de recubrimientos metálicos

Nesta pesquisa, foi realizado o projeto de uma nova configuração de células laboratoriais para aplicação de revestimentos eletrolíticos metálicos, tais como: galvanoplastia, cromagem, cromagem, anodização, entre outros. Para o projeto desta célula, foram definidas variáveis com faixas específicas, tais como: volume entre 100 e 500 ml de solução eletrolítica, tamanho do cátodo entre 0,1 e 0,33 dm2 de área exposta, ânodos entre 1 e 2 vezes a área do cátodo. Uma fonte de corrente com densidade máxima de 9 A/dm2 foi adaptada à célula, além disso, apresenta uma variação na distância entre o ânodo e o cátodo por meio de guias deslizantes para otimizar os processos de investigação. O recipiente onde a solução eletrolítica é depositada, na célula, é refratário ao tipo Pyrex e sua cobertura é feita em ABS (Acrylonitrile Butadiene Styrene) para evitar deterioração devido aos efeitos da corrosão por soluções eletrolíticas.Para o posicionamento dos eletrodos, foi projetado um suporte de eletrodo (suporte de ânodo e suporte de cátodo) com características intercambiáveis para vários ânodos e cátodos, conforme exigido pela experimentação. Para validar o comportamento adequado da célula, foi depositado um revestimento de zinco no aço 1020, obtendo um revestimento eletro-zinco homogêneo e contínuo. A célula de eletrocoating permite experimentar diferentes tipos de substratos, como aços, ligas de alumínio ou titânio, entre outros, em aplicações industriais finais ou em pré-processos.In this research, the design of a new laboratory cell configuration for the application of metallic electrolytic coatings such as: electroplating, chrome plating, copper plating, anodizing, among others. For the design of this cell, variables with specific ranges such as: a volume between 100 and 500 ml of the electrolytic solution, a cathode size between 0.1 and 0.33 dm2 of the exposed area, anodes between 1 and 2 times the cathode area, were defined. A current source with a maximum density of 9 A/dm2. Was adapted to the cell, in addition, it presents a variation in the distance between anode and cathode by means of sliding guides to optimize the investigation processes. The container where the electrolytic solution is deposited, in the cell is made of Pyrex type refractory and its cover was made of ABS (Acrylonitrile Butadiene Styrene) to avoid deterioration due to the effects of corrosion due to electrolytic solutions. For the positioning of the electrodes, it was designed an electrode holder (anode holder and cathode holder) with interchangeable characteristics for multiple anodes and cathodes as required by experimentation. To validate the proper behavior of the cell, a Zinc coating on 1020 steel was deposited, obtaining a homogeneous and continuous electrozinc coating. The electrocoating cell allows to experiment with different types of substrates such as steels, aluminum or titanium alloys, among others, in final industrial applications or in pre-processes.En esta investigación se realizó el diseño de una nueva configuración de celda de laboratorio para la aplicación de recubrimientos electrolíticos metálicos tales como: electrozincado, cromado, cobrizado, anodizado, entre otros. Para el diseño de esta celda se delimitaron variables con rangos específicos como: un volumen entre 100 y 500 ml de solución electrolítica, un tamaño de cátodo entre 0,1 y 0,33 dm2 de área expuesta, ánodos entre 1 y 2 veces el área del cátodo, se adecuó a la celda una fuente de corriente con densidad máxima de 9 A/dm2, además, presenta una variación en la distancia entre ánodo y cátodo mediante guías deslizantes para optimización de los procesos de investigación. El recipiente donde se deposita la solución electrolítica, en celda está fabricado en refractario tipo Pyrex y la cubierta de la misma fue fabricada en ABS (Acrylonitrile Butadiene Styrene) para evitar su deterioro por efectos de la corrosión debida a las soluciones electrolíticas, para el posicionamiento de los electrodos se diseñó un soporte porta electrodos (porta ánodo y porta cátodo) con características intercambiables para múltiples ánodos y cátodos según lo exija la experimentación. Para validar el adecuado comportamiento de la celda se realizó la deposición de un recubrimiento zinc sobre acero 1020 obteniendo un electrozincado homogéneo y continuo. La celda de electrorecubrimiento permite experimentar diferentes tipos de sustratos como aceros, aleaciones de aluminio ó titanio, entre otros, en aplicaciones industriales finales o en preprocesos

Wear Resistance of Thermal Spray WC-Co-VC Nanostructured Coatings

Thermally sprayed WC-Co-VC coatings are widely used based on their resistance to abrasive wear. This chapter shows the fabrication procedure of bimodal WC-Co-VC coatings applied by a high-velocity oxy-fuel (HVOF) thermal spray process. We analyzed the effects of the mixture content of the nanostructure and microstructure phase on the mechanical properties and wear resistance of the coating. Additionally, VC was added to the bimodal mixture and it presented the best characteristics. The combination of VC additions and a bimodal WC particle size distribution in the WC-Co coatings proved successful in increasing their mechanical properties, which permitted the coatings processed in this work to show better mechanical properties than those reported in the literature for coatings having exclusively a bimodal WC particles size distribution or those only doped with VC additions. The effects of nanostructured phase contents on the microstructure and wear resistance of the coating are included

Influencia del tratamiento térmico en el comportamiento corrosivo de las aleaciones aluminio-litio AA2099 Y AA2055

Recientemente, las aleaciones de Al-Li han llamado la atención por su uso en estructuras críticas de peso y rigidez utilizadas en aplicaciones aeronáuticas, aeroespaciales y militares ya que presentan mejores propiedades, como baja densidad y alta resistencia especifica en comparación con las aleaciones comerciales de Aluminio. Estos parámetros (densidad y resistencia especifica) no solo son factores de medición de rendimiento de los materiales aeroespaciales, también permiten controlar las dimensiones de la aeronave y los componentes aeroespaciales por medio de las propiedades de la tolerancia al daño y durabilidad. La adición de litio (no mayor al 1.8%) es clave para la reducción de la densidad (por cada 1 % de litio existe una reducción del 3% equivalente a 0.079g/cm3) y un incremento en el módulo elástico (aprox. por cada 1% de litio incrementa un 6%). El objetivo de este estudio es determinar la susceptibilidad a la corrosión localizada de las aleaciones de Aluminio-Litio AA2099 y AA2055 con distintos tratamientos térmicos, T8, T6 y T0 en una solución acida (H2SO4 1%) y en una solución salina (NaCl 3.5%). Se caracterizó electroquímicamente con la técnica de Curva de Polarización Potenciodinámica

Localized corrosion of 15–5 PH and 17–4 PH stainless steel in NaCl solution

The importance in the selection of materials in the aeronautical industry for the manufacture of an aircraft is related to the fact that the materials are present during the life cycle of the aircraft. In particular, the precipitation hardening (PH) stainless steel is used in components that require the combination of excellent mechanical properties, as well as corrosion resistance due to aircraft exposure in harsh environments. Inherently corrosion resistant steels achieve an important characteristic which is passivation by forming a protective layer of chromium oxide on the surface. This research aimed to conduct an analysis of the localized corrosion on stainless steel 15–5 PH and 17–4 PH, used on fasteners or engine components. The steels were evaluated in a 3.5 wt.% NaCl solution, using the electrochemical technique of cyclic potentiodynamic polarization curves (CPP) according to the ASTM 61–86 standard. The microstructural analysis was performed by optical microscopy (OM) and scanning electron microscopy (SEM). The results indicated that CPP curves showed a positive hysteresis, indicating pitting localized corrosion and the corrosion current density of the 15–5 PH and 17–4 PH stainless steels were 1.31 × 10‒8 and 2.70 × 10‒8 A/cm2

Effect of Citric Acid Hard Anodizing on the Mechanical Properties and Corrosion Resistance of Different Aluminum Alloys

Hard anodizing is used to improve the anodic films’ mechanical qualities and aluminum alloys’ corrosion resistance. Applications for anodic oxide coatings on aluminum alloys include the space environment. In this work, the aluminum alloys 2024-T3 (Al-Cu), 6061-T6 (Al-Mg-Si), and 7075-T6 (Al-Zn) were prepared by hard anodizing electrochemical treatment using citric and sulfur acid baths at different concentrations. The aim of the work is to observe the effect of citric acid on the microstructure of the substrate, the mechanical properties, the corrosion resistance, and the morphology of the hard anodic layers. Hard anodizing was performed on three different aluminum alloys using three citric–sulfuric acid mixtures for 60 min and using current densities of 3.0 and 4.5 A/dm2. Vickers microhardness (HV) measurements and scanning electron microscopy (SEM) were utilized to determine the mechanical characteristics and microstructure of the hard anodizing material, and electrochemical techniques to understand the corrosion kinetics. The result indicates that the aluminum alloy 6061-T6 (Al-Mg-Si) has the maximum hard-coat thickness and hardness. The oxidation of Zn and Mg during the anodizing process found in the 7075-T6 (Al-Zn) alloy promotes oxide formation. Because of the high copper concentration, the oxide layer that forms on the 2024- T6 (Al-Cu) Al alloy has the lowest thickness, hardness, and corrosion resistance. Citric and sulfuric acid solutions can be used to provide hard anodizing in a variety of aluminum alloys that have corrosion resistance and mechanical qualities on par with or better than traditional sulfuric acid anodizing

Comportamiento electroquímico de corrosión de un acero inoxidable sinterizado con diferentes adiciones de boro

Powder metallurgy (PM) is an effective method tomanufacture high quality and accurate parts at alow cost. However, the use of these parts is limiteddue to their low sintered density, which reduces thecorrosion resistance. The objective of the presentwork was to determine the corrosion behavior of409Nb stainless steel specimens sintered and dopedwith different boron contents. The boron is addedto promote the formation of a liquid phase duringsintering at 1,150 oC, which consequently seducesthe amount of porosity and increases the density,resulting in an improved corrosion resistance. Forthis study the techniques of linear polarizationresistance (LPR) and electrochemical noise (EN) inboth potential and current were used. The LPR andEN techniques were used to know the corrosionbehavior of specimens with and without boronadditions in two solutions, namely 0.5M of H2SO4and 0.5M of NaCl. The results obtained allowed toestimate the corrosion rate and disclose the corrosionmechanism. It was concluded that the specimensdoped with boron are more susceptible to corrosionin both solutions due to the precipitation ofchromium rich compounds. The EN measurementsindicate attack by mixed corrosion in the H2SO4solution, whereas in the NaCl solution the samplessuffered localized corrosion.La pulvimetalúrgia (PM) es un método efectivo parafabricar piezas de alta calidad, precisas y a un bajocosto. Sin embargo, el uso de este tipo de materialeses limitado debido a su densidad de sinterizadomás baja, que deteriora el comportamiento de lacorrosión del producto final. El objetivo del trabajofue determinar el comportamiento de corrosión enpiezas de acero inoxidable 409Nb, sinterizadas ydopadas con diferentes contenidos de boro. El borose adiciona para promover la formación de faselíquida durante la sinterización a una temperaturade 1,150 oC, con lo cual se consigue un aumentode la densidad, ya que es necesaria para mejorarla resistencia a la corrosión. Para este estudio seempleó la técnica de resistencia a la polarizaciónlineal (RPL) y ruido electroquímico (RE) enpotencial y en corriente. Las técnicas de RPL y RNfueron empleadas para conocer el comportamientode corrosión de las muestras con y sin adiciones deboro en dos soluciones de prueba, 0.5M H2SO4 y0.5M NaCl. Los resultados permitieron estimarla velocidad de corrosión y el posible mecanismode corrosión de las muestras sinterizadas. Losresultados indican que las muestran con adicionesde boro son más susceptibles a la corrosión debidoa la precipitación de carburos de cromo en lasdos soluciones. Las mediciones de RE indican unmecanismo de ataque por corrosión mixta en lasmuestras de PM en la solución 0.5M H2SO4, mientrasque las que se sometieron a la solución 0.5M NaClpresentaron corrosión localizada

Experimental Study of the Influence of Stitched Nylon Threads in Glass-Fiber-Reinforced Polymer Two-Dimensional Multilayer Composite on Tensile Strength

Stitched filaments are known to modify the mechanical properties of glass-fiber-reinforced polymers 2D (GFRPs 2D), so studying the effect on mechanical properties is underway to determine the critical variables involved. This research focuses on the study of the tensile strength effect of stitched low-density Barkley FBA BGQS15-15 nylon monofilament on biaxial E-Glass Saertex 830 g/m2 (+/−45°) cured with Polyester Sypol Resin 8086 CCP using a vacuum infusion process. Four specimens were made with longitudinal distances between the stitched reinforcements of 0.5, 1.0, 1.5, and 2.0 cm, respectively. Tensile strength tests based on standard ASTM D3039 were performed to study how stitching can affect toughness, Young’s modulus, deformation, ultimate strength, and yield strength. The results indicated that the stitching increases Young’s modulus up to 99.2%, UTS is increased by up to +3.14%, deformation decreases by up to −41.66%, and toughness decreases by up to −36.89%. Although the stitching’s main function is to increase interlaminar resistance, it also induces the formation of stress concentrations by the new threads, and premature failure in the matrix was shown

Material fotoelastico para estudio de elementos reforzado con acero

En este articulo, se muestra la aplicabilidad de una resina epóxica comercial para fabricar modelos fotoelásticos en los que se puede colocar una pieza de acero en su interior antes de su fraguado. El resultado obtenido es una pieza compuesta, en donde no existen esfuerzos residuales en la interfase acero-resina epóxica. Se evalúan los esfuerzos de adherencia para una viga simple reforzada, simulando al concreto armado, mediante fotoelasticidad y elemento finito