Papers by J. Genescá-llongueras
ECS Transactions, 2009
The Galvanic Cathodic Protection system problem lies in its capacity to drive an adequate protect... more The Galvanic Cathodic Protection system problem lies in its capacity to drive an adequate protective protection current from the galvanic anode to the embedded steel reinforcement. This study investigates the reaction mechanism, based on Electrochemical Impedance Spectroscopy (EIS), of the cathodic protection system by thermo sprayed zinc anodes to which LiBr and H2O have been added as humectants. Six reinforced slabs were tested. The specimens were placed in two different Relative Humidity cells. Electrochemical Impedance Spectroscopy and conventional electrochemical properties such as potential, galvanic current and polarization decay of the anode were routinely measured over a 150 days after the humectants addition. It was found that the LiBr notably improved the protective galvanic current; however this improvement was only temporary. Relative humidity had a greater impact than the LiBr addition on the concrete's resistivity.
Tecnologia y Ciencias del Agua, 1991
Se comparan los tres metodos mas utilizados para calcular la velocidad de corrosion: el gravimetr... more Se comparan los tres metodos mas utilizados para calcular la velocidad de corrosion: el gravimetrico, en el cual se determina la velocidad global o promedio a partir de la perdida de peso experimentada por probetas metalicas sumergidas en un electrolito durante un periodo determinado y electroquimicos: el de resistencia de polarizacion y el de extrapolacion de Tafel, en los cuales se determina la velocidad de corrosion instantanea. Se discute bajo que condiciones se puede utilizar cada uno de los metodos y en que casos son equivalentes los valores de la velocidad de corrosion obtenidos por cada uno.
Key Engineering Materials, 2016
This work is part of the DURACON Ibero-American project, which seeks to characterize concrete dur... more This work is part of the DURACON Ibero-American project, which seeks to characterize concrete durability under environmental conditions, based on reinforced concrete sample exposure in at least two different atmospheres (marine and urban), for each of the 11 countries in the project. Specimens were exposed to the environmental conditions of 13 Mexican sites (8 urban and 5 marine atmospheres). Concrete specimens were 15 x 15 x 30 cm, with 6 rebars each, and three concrete covers (15, 20 and 30 cm). Two concrete mixtures were used with water/cement ratios of 0.45 and 0.65, respectively. Six reinforced and six plain concrete specimens were placed on each exposure site. Environmental data was collected on each exposure site, including rainfall, relative humidity, time of wetness, temperature, wind velocity, and carbon dioxide/chloride concentrations. Corrosion rates and potentials, as well as concrete resistivity were measured in the reinforced samples. Carbonation depths were measured ...
Materials and Corrosion, 2004
This work presents the electrochemical results obtained during the study of the corrosion of X52 ... more This work presents the electrochemical results obtained during the study of the corrosion of X52 pipeline steel sample, immersed in brines containing H 2 S, under turbulent flow conditions. Linear polarisation resistance (LPR), electrochemical impedance spectroscopy (EIS), Electrochemical Noise (EN) and polarisation curves were used in order to determine the effect of turbulent flow upon the corrosion kinetics of the steel. It was found that flow has a considerable influence upon the electrochemical process occurring on the surface of the steel and corrosion rate is increased.
This work presents the electrochemical results obtained during the corrosion study of X52 pipelin... more This work presents the electrochemical results obtained during the corrosion study of X52 pipeline steel sample, immersed in “sour” solution under turbulent flow conditions at 60°C. In order to obtain information on the corrosion kinetics, weight loss method, linear polarization resistance, impedance and polarization curves were used at different immersion times. In order to control the turbulent flow conditions, a rotating cylinder electrode was used at two different rotation rates, 0 and 1000 rpm. A surface analysis was carried out in order to identify the corrosion morphology and the corrosion product formed on the steel sample. In general, it was found that flow has a considerable influence upon the electrochemical process occurring on the surface of the steel. It was observed as the flow rate increased the corrosion rate also increased. In surface analysis three phases were found, mackinawite (Fe,Ni) 1+xS ,pyrrhothite (Fe(1-x)S) and marcasite (FeS2). In addition, a “localized ...
Corrosion, 2016
This paper presents the results, after a long term evaluation, in marine environments, from an Ib... more This paper presents the results, after a long term evaluation, in marine environments, from an Iberoamerican project called "Effect of the environment on reinforcement durability" (DURACON). This project correlates the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures in nine countries (Bolivia,
Materials Science Forum, 2014
Electrochemical Noise (EN) measurements for low carbon pipeline steel (X52) samples were carried ... more Electrochemical Noise (EN) measurements for low carbon pipeline steel (X52) samples were carried out in 3.5% NaCl aqueous and NACE solutions. Both testing solutions were saturated with hydrogen sulphide (H2S) at 20 and 60 oC, under static conditions. EN data was analysed in the time domain. Parameter such as Electrochemical Noise Resistance (Rn) and Localization Index (LI) were determined from the analysis in the time domain. Also, Rn results are compared with traditional Linear Polarization Resistance (LPR) data. A superficial analysis was carried out by a scanning electron microscopy (SEM) with Energy Dispersive X-Ray analyses (EDX). A good correlation was observed among the used techniques and relevant electrochemical data related to the corrosion phenomena was obtained. According to Rn, the corrosion rate (CR) values of the steel sample immersed in 3.5% NaCl are higher than the CR of the steel samples immersed in NACE solution. The morphology of the corrosion process obtained by...
Electrochimica Acta, 2008
The action of Desulfovibrio vulgaris (Dv) during a corrosion process has been reported in literat... more The action of Desulfovibrio vulgaris (Dv) during a corrosion process has been reported in literature, but the influence of imidazoline in the formation of biofilms is not clear, as well as the effect of bacteria on the efficiency of the corrosion inhibitors. The aim of this work is to determine the behavior of bacteria in the presence of imidazoline. Therefore, the growth of Dv, isolated and characterized from a morphological point of view, was monitored during 21 days, during which synthetic seawater was used as the culture medium, according to the ASTM D665-98 standard. Electrochemical noise (EN) was employed to establish the corrosion type generated by the microorganism on an AISI 1018 steel cylinder. The attack was observed using scanning electron microscopy (SEM). In order to evaluate the efficiency of the corrosion inhibitor, Tafel extrapolation was used; the optimum concentration of the inhibitor was used in the presence of sulphate-reducing bacteria (SRB). In general, two forms of corrosion were observed: localized corrosion (in the LAG phase) and mixed corrosion (in the LOG phase).
Se presenta un metodo sencillo para establecer la tendencia de un determinado cuerpo de agua a la... more Se presenta un metodo sencillo para establecer la tendencia de un determinado cuerpo de agua a la incrustacion o a la corrosion, mediante el calculo del pH al cual el agua estara saturada con Calcio Carbonico (indice de estabilidad de Ryznar), para un contenido dado de solidos disueltos totales (residuo filtrable a 105°C), calcio y alcalinidad.
Global Journal of Environmental Science and Management, 2021
BACKGROUND AND OBJECTIVES: Atmospheric zinc corrosion in the Mexico City Metropolitan area has lo... more BACKGROUND AND OBJECTIVES: Atmospheric zinc corrosion in the Mexico City Metropolitan area has long been attributed mainly to the effect of pollutants such as sulfur dipxide. There are changes in the urban atmosphere's chemical composition due to the implementation of air quality policies focused on reducing the emission of sulfur dipxide and other pollutants. This study's objectives were to estimate and map the contribution of nitric acid on zinc's atmospheric corrosion process METHODS: The impact of nitric acid on zinc is feasible to estimate using a function for a multi-pollutant situation. This function contemplates the sum of two contributions: one of nitric acid and another that includes sulfuric acid and climatic parameters. The multi-pollutant function is suitable to apply in areas without the strong influence of chlorides and tropical and subtropical climates, comparable to the Mexico City Metropolitan area. FINDINGS: The results showed that spatial and temporal...
Surface and Coatings Technology
Revista de Metalurgia, 1995
Resumen El cobre es el elemento principal de las aleaciones Cu-Ni recomendadas para aplicaciones ... more Resumen El cobre es el elemento principal de las aleaciones Cu-Ni recomendadas para aplicaciones marinas. En este trabajo se presenta el comportamiento electroquímico del cobre con los diferentes componentes del agua de mar y el efecto de estos sobre la forma de ataque del cobre. Se observó que los iones cloruro, en unión con los iones sulfato, son los principales causantes del fenómeno de corrosión por picaduras, existiendo, además, una relación significativa entre el potencial crítico de picado (E^) y la relación (Cl""/SO^") de tipo parabólico, lo cual pone de manifiesto la importancia del ion sulfato en el fenómeno de corrosión por picaduras como promotor de este tipo de mecanismo. Palabras clave: Cobre. Agua de mar. Picaduras. Corrosión localizada.
Journal of Solid State Electrochemistry, 2003
The study of a plain carbon steel (AISI 1020) in Na 2 SO 4 aqueous solutions at different concent... more The study of a plain carbon steel (AISI 1020) in Na 2 SO 4 aqueous solutions at different concentrations was carried out by electrochemical impedance spectroscopy (EIS) in order to determine the corrosion mechanism and to obtain representative corrosion rates of the system. EIS was used to measure corrosion current densities at high concentrations in the range 0.1-1 wt% Na 2 SO 4 , but in the low concentration range, from 0.001 to 0.01 wt%, a scattered Nyquist plot was obtained. Other electrochemical techniques, such as polarization resistance (PR), Tafel plots and electrochemical noise (EN), were also used in this analysis. The charge transfer resistance was determined and compared with the PR and noise resistance.
Revista de Metalurgia, 1995
Resumen El cobre es un material frecuentemente empleado para la construcción de tuberías, sujeto ... more Resumen El cobre es un material frecuentemente empleado para la construcción de tuberías, sujeto a la acción de los cloruros, que ocasionan corrosión por picaduras. El presente trabajo busca determinar un posible mecanismo de corrosión por picaduras en el cobre por la acción de los cloruros, apoyándose en la información que ofrecen las técnicas electroquímicas de polarización, espectroscopia de impedancia faradaica y ruido electroquímico.
Mass Transfer - Advanced Aspects, 2011
Journal of Solid State Electrochemistry, 2009
The role of hydrogen peroxide in the formation of cerium conversion coatings by immersing AISI 10... more The role of hydrogen peroxide in the formation of cerium conversion coatings by immersing AISI 1010 commercial carbon steel substrates into solutions containing various concentrations of CeCl3 (0.1, 1, and 10 g L−1) has been investigated as an alternative method for their protection against corrosion. The deposits prepared from the solutions with H2O2 consist of yellow thin and non-uniform coatings with
Corrosion, 2014
ABSTRACT The effect of hydrotalcite (HT) on the protection of aluminum alloy by sol-gel films was... more ABSTRACT The effect of hydrotalcite (HT) on the protection of aluminum alloy by sol-gel films was investigated by electrochemical impedance spectroscopy (EIS) and electrochemical noise measurements (ENM). Samples of 1, 5, and 10 wt% of HT were tested. Improved performance was observed and the main action of HT was explained by its buffering capacity, which reduces locally aggressive conditions and maintains the stability of the films. A comparison between EIS and ENM results showed differences in the response of the coatings that may have come from pitting activation triggered by EIS measurements at the beginning of immersion, which, in turn, may lead to premature failure and erroneous coating evaluation.
British Corrosion Journal, 2001
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Papers by J. Genescá-llongueras