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Search Results: 1 - 10 of 442048 matches for " J. G. Gonzalez-Rodriguez "
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A Study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as Green Corrosion Inhibitors for Carbon Steel in Sulfuric Acid  [PDF]
M. J. Garcia-Ramirez, G. F. Dominguez Pati?o, J. G. Gonzalez-Rodriguez, M. L. Dominguez-Pati?o, J. A. Dominguez-Pati?o
Advances in Materials Physics and Chemistry (AMPC) , 2016, DOI: 10.4236/ampc.2016.62002
Abstract: A study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as eco-friendly corrosion inhibitors for 1018 carbon steel in 0.5 M H2SO4 has been carried out by using weight loss tests, potentiodynamic polarization curves and electrochemical impedance spectroscopy measuremnts. Results have shown that the three extracts performed as good corrosion inhibitors, but the Eruca vesicaria exhibited the best performance followed by Erythrina americana. The three inhibitors formed a protective, passive film which protected the steel from corrosion. This was because they contain antioxidants present in their molecular structure with heteroatoms such as N, C and O like phenols, amino acids, etc., which react with metal and environment to form the protective film.
Corrosion Inhibition of Carbon Steel in Acidic Mediaby Using Actinidia deliciosa (Kiwifruit) Extract  [PDF]
M. I. Arias-Montoya, G. F. Dominguez-Pati?o, J. G. Gonzalez-Rodriguez, J. A. Dominguez-Pati?o, M. L. Dominguez-Pati?o
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.511045
Abstract: The corrosion inhibition of 1018 carbon steel in 0.5 M H2SO4 by using Actinidia deliciosa (Kiwifruit) peel extract has been investigated by using potentiodynamic polarization curves and electro-chemical impedance spectroscopy. Two kinds of extracts are investigated, one from the tender, and another one from ripe Actinidia deliciosa. Concentrations include 0, 25, 50, 75, and 100 ppm at room temperature. Results indicate that both kind of extracts acted as good corrosion inhibitors, is more efficient in the ripe extract. Corrosion inhibition efficiency increases with increasing its concentration for ripe extract, whereas for the tender Actinidia deliciosa, the higest inhibitor efficiency is obtained by adding 25 ppm and decresaing with a further increase in its concentration. Both extracts improve the passive film properties by decreasing the passive current density values. It is found that the corrosion inhibition is due to the presence of heteroatoms present in Actinidia deliciosa, mainly quercitine, which is physically adsorbed in the steel following a Frumkin type of adsorption isotherm which forms a protective film.
Use of Rosmarinus officinalis as Green Corrosion Inhibitor for Carbon Steel in Acid Medium  [PDF]
M. A. Velázquez-González, J. G. Gonzalez-Rodriguez, M. G. Valladares-Cisneros, I. A. Hermoso-Diaz
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.52009
Abstract:

The use of Rosmarinus officinalis as a corrosion inhibitor for 1018 carbon steel in 0.5 M H2SO4 has been evaluated by using weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy techniques at 25°. Inhibitor concentrations were included within the range between 0 and 1000 ppm C using three extract solvents, namely acetone, hexane and methanol. Results have shown that Rosmarinus officinalis is a good corrosion inhibitor with its efficiency increasing with the concentration. The best efficiency was obtained with the hexanic extract. The passivating film properties of the steel were improved by the presence of flavonoids in the extract.

Corrosion Inhibition of Carbon Steel in 0.5?M H2SO4 by Phtalocyanine Blue
J. C. Valle-Quitana,G. F. Dominguez-Pati?o,J. G. Gonzalez-Rodriguez
ISRN Corrosion , 2014, DOI: 10.1155/2014/945645
Abstract: Phthalocyanine blue dye has been investigated as a carbon steel corrosion inhibitor in 0.5?M sulfuric acid by using polarization curves, electrochemical impedance spectroscopy, and gravimetric tests. Dye concentrations included 0, 100, 200, 400, 600, 800, and 1000?ppm, whereas testing temperatures were 25, 40, and 60°C. Results indicated that phtalocyanine blue is a good corrosion inhibitor with its efficiency increasing with the concentration up to 40°C, but it increases at 60°C. Inhibitor improves the passive film properties and it forms an adherent, compact, protective film, acting, therefore, as an anodic-type inhibitor. At 25 and 40°C the corrosion process was under charge transfer, whereas at 60°C the adsorption/desorption of some species from the metal surface controlled the corrosion process. 1. Introduction Organic compounds containing atoms such as nitrogen, sulphur, and oxygen are commonly used to reduce the corrosion attack on steel in acidic media. These compounds adsorb on the metal surface, block the active sites on the surface, and thereby reduce the corrosion process [1–6]. The inhibiting action of such compounds is based on the adsorption ability of their molecules, where the resulting adsorption film isolates the metal from the aggressive media. The corrosion inhibition of organic compounds is related to their adsorption properties. Adsorption depends on the nature and the state of the metal surface, on the type of corrosive environment, and on the chemical structure of the inhibitor [7]. Studies report that the adsorption of organic inhibitors mainly depends on some physicochemical properties of the molecule, related to its functional groups, to the possible steric effects and electronic density of donor atoms; adsorption is suppose, also to depend on the possible interaction of the -orbitals of the inhibitor with the d-orbitals of the surface atoms, which induce greater adsorption of the inhibitor molecules onto the surface of metal, leading to the formation of a corrosion protection film [8]. Recently, there has been a lot of attention paid to the use of organic dyes as potential corrosion inhibitors for different metalsenvironments [9–24]. Thus, Oguzie evaluated the use of Congo red [9], methylene blue [10], indigo blue [11], safranin-o, thymol blue, and fluorescein [12] as corrosion inhibitors for mild steel in acidic media, although in some cases they evaluated these dyes for aluminum in hydrochloric acid [13]. Alizarin yellow and Bromophenol blue have been used also but now studying the synergistic effect of iodide ions for the
Corrosion Behavior of Mg-Al/TiC Composites in NaCl Solution
L. A. Falcon,E. Bedolla B.,J. Lemus,C. Leon,I. Rosales,J. G. Gonzalez-Rodriguez
International Journal of Corrosion , 2011, DOI: 10.1155/2011/896845
Abstract: The corrosion behavior of TiC particles reinforced Mg-Al alloy in 3.5% NaCl solution has been evaluated using electrochemical techniques. Tested alloys included an Mg-9Al (Mg AZ91E) alloy with and without 56?wt. % TiC particles. Electrochemical techniques included potentiodynamic polarization curves, linear polarization resistance, electrochemical noise, and electrochemical impedance spectroscopy measurements. All techniques showed that the composite exhibited a lower corrosion rate than the base alloy. Evidence of galvanic effects that increased the composite corrosion rate was found between the matrix and the TiC particles. Additionally, the tendency to suffer from pitting corrosion was higher for the base alloy than that for the composite. Electrochemical impedance results showed the importance of adsorption/diffusion phenomena in both materials. 1. Introduction Nowadays, aluminum matrixes are widely used in metallic matrix composites (MMCs), because they have the highest priority in applications where a combination of corrosion resistance, low density, and high mechanical performance are required, such as in the automotive and aerospace industry. The reinforcement of an aluminum matrix, based on the use of TiC particles is interesting because of its good wettability [1, 2] which results in a clean and strong interface [2–4]. While aluminum alloys are the most commonly used matrix in metal-ceramic composites, it has been reported that the addition of TiC, as reinforcement, improves the mechanical properties at room and high temperatures. However, research in new systems is required due to rapid increase in technological development. Therefore, it could be appreciated as an increasing interest in the use of magnesium and its alloys as a metallic matrix for MMC composites. The main disadvantage of magnesium is the high chemical reactivity due to its negative electrochemical potential; this greatly restricts its industrial applications, and the same disadvantage has been found for Mg-Al-Zn alloys, being Mg AZ91, the most significant alloy. Researches on metallic-based matrix composites using magnesium are considerable fewer than those done for aluminum [5–10]. Many studies have been carried out to determine the Mg-Al-Zn corrosion behavior. Pardo et al. [11] concluded that corrosion damage was mainly caused by formation of a Mg(OH)2 corrosion layer. AZ80 and AZ91D alloys revealed the highest corrosion resistance. The relatively fine β-phase (Mg17Al12) network and the aluminum enrichment produced on the corroded surface were the key factors limiting
Corrosion Behavior of Fe40Al Alloy with Additions of Ti, Ag, and Cr in Molten KCl+
R. Ademar,J. G. Gonzalez-Rodriguez,J. Uruchurtu,J. Porcayo-Calderon,V. M. Salinas-Bravo,G. Dominguez-Pati?o,A. Bedolla-Jacuinde
International Journal of Corrosion , 2012, DOI: 10.1155/2012/146486
Abstract: The effect of 2.5?at.% Cr, Ti, and Ag on the corrosion behavior of Fe40Al intermetallic alloy in KCl-ZnCl2 (1?:?1?M) at 670°C has been evaluated by using electrochemical techniques. Techniques included potentiodynamic polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) measurements. Results have shown that additions of both Cr and Ti were beneficial to the alloy, since they decreased its corrosion rate, whereas additions of Ag was detrimental, since its additions increased the corrosion rate, although the alloy was passivated by adding Ag or Cr. The best corrosion performance was obtained with the addition of Cr, whereas the highest corrosion rate was obtained by adding Ag. This is explained in terms of the stability of the corrosion products formed film. 1. Introduction Sodium and potassium impurities present in the form of chloride or sulfates are very corrosive constituents under certain combustion conditions such as waste incinerators and biomass-fired boilers [1, 2]. Early failure of the thermal components frequently occurs due to the complex reactions between the metallic materials and the hostile combustion environment. Incineration has become a viable technology for disposing of various types of wastes, including municipal, hospital, chemical, and hazardous. Problems with process equipment resulting from fireside corrosion have been frequently encountered in incinerators. The major problem is the complex nature of the feed (waste) as well as corrosive impurities which form low-melting point compounds with heavy and alkali metal chloride which prevents the formation of protective oxide scales and then causes an accelerated degradation of metallic elements [1]. In particular, under reducing conditions such as those typical of the operation of waste gasification plants or even under localized reducing conditions, which frequently arise in the case of incorrect operation of waste incineration systems, it is difficult to form protective oxide scales such as Cr2O3, SiO2, and Al2O3 on the surface of structural materials. Thus, the corrosion attack can be further enhanced under reducing atmospheres in the presence of salt deposits [2]. The effect of individual KCl, NaCl, and their mixtures with heavy metal chlorides or sulfates on the corrosion behavior of a series of alloy systems has been studied in detail so far [3–9]. It is generally realized that Cr is not as effective element for corrosion resistance of Fe-base and Ni-based alloys due to chloride attack. In contrast, alumina- (Al2O3) forming
Effect of Minor Alloying Elements on the Corrosion Behavior of Fe40Al in NaCl-KCl Molten Salts
G. Salinas,J. G. Gonzalez-Rodriguez,J. Porcayo-Calderon,V. M. Salinas-Bravo,M. A. Espinoza-Medina
International Journal of Corrosion , 2012, DOI: 10.1155/2012/185842
Abstract: The hot corrosion behavior of Fe40Al intermetallic alloyed with Ag, Cu, Li, and Ni (1–5 at.%) in NaCl-KCl (1?:?1?M) at 670°C, typical of waste gasification environments, has been evaluated by using polarization curves and weight loss techniques and compared with a 304-type stainless steel. Both gravimetric and electrochemical techniques showed that all different Fe40Al-base alloys have a much higher corrosion resistance than that for stainless steel. Among the different Fe40Al-based alloys, the corrosion rate was very similar among each other, but it was evident that the addition of Li decreased their corrosion rate whereas all the other elements increased it. Results have been explained in terms of the formation and stability of an external, protective Al2O3 layer. 1. Introduction Sodium and potassium impurities present in the form of chloride or sulfates are very corrosive constituents under certain combustion conditions such as waste incinerators and biomass-fired boilers [1, 2]. Early failure of the thermal components frequently occurs due to the complex reactions between the metallic materials and the hostile combustion environment. Problems with process equipment resulting from fireside corrosion have been frequently encountered in incinerators. The major problem is the complex nature of the feed (waste) as well as corrosive impurities which form low-melting point compounds with heavy and alkali metal chlorides which prevent the formation of protective oxide scales and then causes an accelerated degradation of metallic elements [1]. In particular, under reducing conditions such as those typical of the operation of waste gasification plants or even under localized reducing conditions, which frequently arise in the case of incorrect operation of waste incineration systems, it is difficult to form protective oxide scales such as Cr2O3, SiO2, and Al2O3 on the surface of structural materials. Thus, the corrosion attack can be further enhanced under reducing atmospheres in the presence of salt deposits [2]. The effect of individual KCl, NaCl, and their mixtures with heavy metal chlorides or sulfates on the corrosion behavior of a series of alloy systems has been studied in detail so far [2–9]. It is generally realized that Cr is not as effective element for corrosion resistance of Fe-based and Ni-based alloys due to chloride attack. In contrast, alumina-(Al2O3-) forming alloys exhibit promising candidate materials considering the better high temperature resistance of alumina over chromia and their properties such as lower cost, low density, high
Hot Corrosion Behavior of High-Chromium, High-Carbon Cast Irons in NaCl-KCl Molten Salts
S. Vuelvas-Rayo,J. G. Gonzalez-Rodriguez,J. Porcayo-Calderon,V. M. Salinas-Bravo,S. I. Maldonado-Ruiz
International Journal of Corrosion , 2012, DOI: 10.1155/2012/479761
Abstract: A study on the corrosion behavior of a series of experimental high-chromium (18.53–30.48?wt.%), high-carbon (3.82–5.17%) cast irons in NaCl-KCl (1?:?1?M) at 670°C has been evaluated by using weight loss technique and compared with a 304-type stainless steel. It was found that all castings had a higher corrosion rate than conventional 304SS and that the addition of Cr increased the degradation rate of the cast irons. Additionally, corrosion rate increased by increasing the C contents up to 4.29%, but it decreased with a further increase in its contents. Results are discussed in terms of consumption of the Cr2O3 layer by the melt. 1. Introduction The molten salt technology has been widely used in the industrial world because of its physical and chemical characteristics, especially its high electrical conductivity, high processing rate, and high diffusion rate. Recently, it has attracted much attention in the fields of jet engines, fuel cells, catalysts, metal refinement, as well as certain combustion conditions such as waste incinerators, biomass-fired boilers, and power stations [1–5]. Therefore, the studies on the corrosion of structural materials for handling high-temperature molten salts have also been continuously carried out. It is generally realized that Cr is not an effective element for corrosion resistance improvement of Fe-based and Ni-based alloys due to chloride salt attack [6–15]. However, by increasing the Cr contents, the corrosion resistance of Fe-based alloys could be increased. Problems with process equipment resulting from fireside corrosion have been frequently encountered in waste incinerators and biomass-fired boilers. The major problem is the complex nature of the feed (waste) as well as corrosive impurities which form low-melting point compounds with heavy and alkali metal chlorides which prevent the formation of protective oxide scales and then cause an accelerated degradation of metallic elements [1]. In particular, under reducing conditions such as those typical of the operation of waste gasification plants or even under localized reducing conditions, which frequently arise in the case of incorrect operation of waste incineration systems, it is difficult to form protective oxide scales such as , SiO2, and on the surface of structural materials. Thus, the corrosion attack can be further enhanced under reducing atmospheres in the presence of salt deposits [2]. High-chromium, high-carbon cast irons are commonly used in industrial conditions subjected to attrition and wear similar to the environment found in mining or coal cement
Is copper an inhibiting factor for primary production in the upwelling waters of Cabo Frio?
Diniz, Ant?nia G.;Hamacher, Claudia;Wagener, Angela de L. R.;Gonzalez-Rodriguez, Eliane;
Journal of the Brazilian Chemical Society , 2003, DOI: 10.1590/S0103-50532003000500018
Abstract: the goal of the present work was to test the hypothesis that inorganic species of copper may inhibit primary production in upwelling waters from the cabo frio region. water samples were collected from four different depths up to 50 m at three stations of cabo frio and nutrient concentration, ph, dissolved oxygen, alkalinity, seston, chlorophyll a, primary production, npp, copper speciation, cu(ii) and cu(i) and complexing capacity were determined. the results indicate that the rate of photosynthesis in nutrient rich waters with higher copper content and lower complexing capacity is significantly reduced. cu(i) made up 2-15% of the total copper, however, there was no evidence to suggest that the photochemical production of cu(i) affects npp.
Is copper an inhibiting factor for primary production in the upwelling waters of Cabo Frio?
Diniz Ant?nia G.,Hamacher Claudia,Wagener Angela de L. R.,Gonzalez-Rodriguez Eliane
Journal of the Brazilian Chemical Society , 2003,
Abstract: The goal of the present work was to test the hypothesis that inorganic species of copper may inhibit primary production in upwelling waters from the Cabo Frio region. Water samples were collected from four different depths up to 50 m at three stations of Cabo Frio and nutrient concentration, pH, dissolved oxygen, alkalinity, seston, chlorophyll a, primary production, NPP, copper speciation, Cu(II) and Cu(I) and complexing capacity were determined. The results indicate that the rate of photosynthesis in nutrient rich waters with higher copper content and lower complexing capacity is significantly reduced. Cu(I) made up 2-15% of the total copper, however, there was no evidence to suggest that the photochemical production of Cu(I) affects NPP.
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