ABSTRACT Periodontal diseases are considered among the most common among oral pathologies. Its frequency is increasingly higher in the population and there are several systemic pathologies and habits that worsen its clinical condition. The objective of this work was to determine the frequency and clinical characteristics of patients with periodontal diseases who attend the periodontics department at the Autonomous University of Asunción in the period from 2011 to 2019. Observational, descriptive, retrospective study, 477 clinical records were processed. of patients from the Department of Periodontics at the Autonomous University of Asunción from 2011 to 2019. The type of sampling used was non-probabilistic for convenience. Of the 477 records, only 317 patients who met the inclusion criteria were analyzed. They were 56.46% female and 43.53% male, the median age was 33 (23-48) years. 53% of the patients had chronic periodontitis and comorbidities such as diabetes and high blood pressure. Only 11.9% were smokers. Regarding diabetic patients, the majority were female and elderly, with chronic periodontitis as the most frequent diagnosis. The most frequent clinical diagnosis of the studied population was chronic periodontitis, followed by gingivitis.

RESUMEN Las enfermedades periodontales son consideradas entre las más comunes entre las patologías bucales. Su frecuencia es cada vez más elevada en la población y existen varias patologías sistémicas y hábitos que empeoran su cuadro clínico. El objetivo de este trabajo fue determinar la frecuencia y características clínicas de pacientes con enfermedades periodontales que acuden a la cátedra de periodoncia en la Universidad Autónoma de Asunción en el período de 2011 al 2019. Estudio Observacional, descriptivo, retrospectivo, se procesaron 477 fichas clínicas de pacientes de la cátedra de Periodoncia de la Universidad Autónoma de Asunción desde el año 2011 al 2019. El tipo de muestreo utilizado fue no probabilístico por conveniencia. De las 477 fichas solo se analizaron 317 pacientes que cumplieron con los criterios de inclusión. Fueron el 56.46 % de sexo femenino y 43,53 % de sexo masculino, la mediana de edad fue de 33 (23-48) años. El 53% los pacientes presentaban periodontitis crónica y comorbilidades como diabetes e hipertensión arterial. Solo el 11,9 % fueron fumadores. En cuanto a los pacientes diabéticos la mayoría eran de sexo femenino y de edad avanzada, presentando como diagnóstico más frecuente la periodontitis crónica. El diagnóstico clínico más frecuente de la población estudiada fue la periodontitis crónica, seguido por la gingivitis.

ABSTRACT Introduction: The oral cavity hosts a large number of microorganisms, such as Gram negative bacilli, and among them, bacteria of great medical importance due to their capacity to cause serious diseases for humans, especially in immunosuppressed patients. The objective of this work was to determine the presence of Gram Negative Bacilli and their patterns of resistance to antibiotics, in a student population of the city of Asunción, in the years 2019 and 2020. Materials and methods: An observational, descriptive cross-sectional study was carried out, where oral cavity swabs were made from 35 students between 18 and 24 years of age, from a private university in the city of Asunción. Informed consent signed by the participants was required and those who had antibiotic treatments were excluded. The samples were obtained with a cotton swab, later they were placed in a transport medium to later be cultured in MacConkey Agar. The culture was carried out for 48 hours at 37° Celsius, then the bacterial identification was carried out. Finally, the antibiogram was performed. Results: Of the 35 students, a frequency of 48,57% of Gram negative bacilli was found. Klebsiella pneumoniae strains were the most frequent (35.29%). The bacteria were found to be highly resistant to Amoxicillin/Clavulanic Acid. Conclusions: The presence of these types of microorganisms can be dangerous for the general health of people, specifically of patients with some type of immunosuppression, due to the great resistance to antibiotics presented by some strains.

RESUMEN Introducción: La cavidad bucal hospeda una gran cantidad de microorganismos, como los bacilos Gram negativos, y entre ellas, bacterias de gran importancia médica debido a su capacidad de producir enfermedades graves para el ser humano, especialmente en pacientes inmunodeprimidos. El objetivo de este trabajo fue determinar la presencia de Bacilos Gram Negativos y sus patrones de resistencia a antibióticos, en una población estudiantil de la ciudad de Asunción, en los años 2019 y 2020. Materiales y métodos: Se realizó un estudio observacional, descriptivo de corte transversal, donde se realizaron hisopados de la cavidad bucal a 35 alumnos de entre 18 a 24 años, de una universidad privada en la ciudad de Asunción. Se requirió consentimiento informado firmado por los participantes y fueron excluidos quienes tuvieron tratamientos antibióticos. Las muestras fueron obtenidas con un hisopo de algodón, posteriormente se colocaron en un medio de transporte para luego ser cultivadas en Agar MacConkey. El cultivo se realizó por 48 horas a 37° centígrados, luego se procedió a la identificación bacteriana. Por último, se realizó el antibiograma. Resultados: De los 35 alumnos se encontró una frecuencia de 48,57% de bacilos Gram negativos. Cepas de Klebsiella pneumoniae fueron las más frecuentes (35,29%). Se observó que las bacterias eran altamente resistentes a la Amoxicilina/Ácido Clavulánico. Conclusiones: La presencia de estos tipos de microorganismos puede ser peligrosa para la salud general de las personas, específicamente de los pacientes con algún tipo de inmunodepresión, debido a la gran la resistencia a antibióticos presentadas por algunas cepas.

ABSTRACT Inhibitors are one of the oldest methods of mitigating corrosion, which is still a current challenging and costly problem. However, traditional inhibitors are toxic and non-biodegradable, which goes against the principles of Green Chemistry, so named for valuing the use of biodegradable and environmentally friendly products. They can be obtained from plants and their residues that, when subjected to some type of processing, generate extracts or oils with important inhibitory potential. In most cases, green inhibitors are organic compounds classified relating to the mechanism as mixed, having polar functional groups that act as adsorption centers on the metallic surface. This study aimed to carry out a systematic review of the literature on inhibitors from species of Brazilian flora and used in an acid environment to prevent corrosion in carbon steel in a specific medium. Brazil presents a rich biodiversity of flora, with more than 46,200 species cataloged in 2020, which provides a wide field of research in this area. The review included 28 different plant species. The results found were promising, with emphasis on the use of parts of vegetables that are normally discarded and show the potential for development and improvement of green inhibitors for future application on an industrial scale.

RESUMO Os inibidores são um dos métodos mais antigos de combate à corrosão, que ainda hoje é um problema desafiador e caro. Porém, os inibidores tradicionais são tóxicos e não biodegradáveis, o que vai contra os princípios da Química Verde, assim denominada por valorizar o uso de produtos biodegradáveis e ambientalmente amigáveis. Os inibidores podem ser obtidos de plantas e seus resíduos que, quando submetidos a algum tipo de processamento, geram extratos ou óleos com importante potencial inibitório. Na maioria dos casos, os inibidores verdes são compostos orgânicos classificados, quanto ao mecanismo, como mistos, possuindo grupos funcionais polares que atuam como centros de adsorção na superfície metálica. Este estudo teve como objetivo realizar uma revisão sistemática da literatura sobre inibidores de espécies da flora brasileira e utilizados em ambiente ácido para prevenir a corrosão em aço carbono. O Brasil apresenta uma rica biodiversidade de flora, com mais de 46.200 espécies catalogadas em 2020, o que proporciona um amplo campo de pesquisa nesta área. A revisão incluiu 28 espécies de plantas diferentes. Os resultados encontrados foram promissores, com destaque para o uso de partes de vegetais que normalmente são descartadas e mostram o potencial de desenvolvimento e aprimoramento de inibidores verdes para futura aplicação em escala industrial.

The inhibition effect of the cocoa bean shell powder (CBSP) on SAE 1008 carbon steel was studied in acidic medium (HCl 0.5 mol L-1) by electrochemical techniques and gravimetric measurements. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to the chemical and morphological characterization. The gravimetric and EIS results showed that the corrosion rate decreases with increasing inhibitor concentration, reaching the maximum value of 97.92% in 1.77 g L-1 inhibitor (highest concentration studied). Even at the lowest concentration (0.44 g L-1) good corrosion inhibition efficiency (96.03%) was observed. The polarization curves indicated that the CBSP acts as a mixed type inhibitor. The inhibitory molecules adsorption followed the Langmuir isotherm model. The inhibitor economic evaluation showed that the use of CBSP is 48-616 times cheaper than traditional inhibitors. The results showed that CBSP is an efficient corrosion inhibitor for carbon steel and its production is financially attractive.

ABSTRACT The malt bagasse is a solid residue, highly produced in the brewing industry. The presence of high levels of antioxidants in its composition makes this residue an attractive possibility as a corrosion inhibitor, besides being a sustainable and low cost alternative to the inorganic procedures currently used to prevent corrosion. In this sense, this work evaluated the efficiency of the malt bagasse powder as a corrosion inhibitor on the surface of AISI 1020 carbon steel, in different concentrations, in acidic medium 0.5 mol.L-1 HCl. The resistance to corrosion was tested by electrochemical techniques, such as electrochemical impedance spectroscopy (EIS) and anodic and cathodic polarization curves. The efficiency of the corrosion inhibitor was evaluated by weight loss tests. Fourier transform infrared spectroscopy (FTIR) and optical microscope surface image analysis were respectively used as chemical and morphological characterization techniques, respectively. From the EIS results, it can be said that the powder has its efficiency increased once the concentration is higher. On the other hand, the polarization curves shows the malt bagasse powder as an inhibitor presents both anodic and cathodic behavior. The weight loss results confirmed the electrochemical results, showing 92.5% efficiency for the 1.77 g.L-1 concentration. The adsorption isotherm on the steel surface follows Languimir’s Isotherm. The FTIR analysis indicates the presence of heteroatoms such as C, N, O, incorporated in functional groups that could be responsible for the inhibitory properties found in the powder. The images obtained from the optical microscope, showed that the corrosion process, in the presence of the inhibitor in the electrolyte, is retarded. Therefore, the results indicate that the malt bagasse powder has the potential to be a corrosion inhibitor for steel in acidic medium, adding value in the beer production chain.

ABSTRACT Carbon steel is used in various applications because of its excellent weldability, good mechanical resistance and low cost. However, its application becomes restricted due to its low corrosion resistance in neutral and acidic media, and it is necessary to use processes to retard the corrosive mechanism, such as the use of inhibitors. Many of the effective synthetic inhibitors used are associated with high cost and some have a high toxicity. In recent years, studies of corrosion inhibitors obtained from natural products have been increasing because they are environmentally sustainable and presents low-cost. Therefore, in the present study, different concentrations of the cocoa shell powder (Theobroma cacao) and hydroalcoholic extract were evaluated as a corrosion inhibitors of SAE 1008 carbon steel in 0.5 mol.L-1 sodium chloride solution. The inhibitory action of the cocoa residue was studied through gravimetric technique and electrochemical impedance spectroscopy (EIS). For the chemical characterization of the inhibitor, the Fourier Transform Infrared Spectroscopy (FTIR) was used. The EIS results showed that the corrosion inhibition efficiency of the steel decreased with the inhibitor concentration, reaching maximum values of 55.97% and 72.93%, for cocoa shell powder and hydroalcoholic extract, respectively. The gravimetric data confirmed the electrochemical results and through the study of the adsorption mechanism it was verified that the adsorbed inhibitor molecules follow the Flory-Huggins isotherm model, for both forms of the inhibitor. For all the concentrations evaluated, the cocoa shell powder did not represent an efficient corrosion inhibitor. In contrast, for the hydroalcoholic extract, at the concentration of 0.44 g.L-1, a good performance was verified as a corrosion inhibitor of SAE 1008 carbon steel in 0.5 mol.L-1 sodium chloride solution.

RESUMO O aço galvanizado é obtido pela imersão do aço carbono em um banho de zinco fundido, sendo esse material muito utilizado na indústria automotiva e de eletrodomésticos. Como todo material metálico, é suscetível à corrosão quando exposto a ambientes corrosivos, necessitando assim de tratamento de superfície para proteção. Atualmente, são utilizados como pré-tratamentos a fosfatização e a cromatização, ambos com restrições ambientais e à saúde humana. O aço galvanizado é obtido pela imersão do aço carbono em um banho de zinco fundido, sendo esse material muito utilizado na indústria automotiva, petroquímica, química, naval, aeronáutica e de linha branca. Apresenta maior resistência à corrosão do que o aço carbono quando exposto a ambientes corrosivos. Para aumentar sua durabilidade e sua resistência à corrosão, passa por um tratamento superficial que seja aderente à sua superfície. Por esta razão, atualmente, são utilizados a fosfatização e a cromatização como pós-tratamento à galvanização, ambos com restrições ambientais e à saúde humana. Por essa razão, estuda-se a viabilidade do uso de silanos como possíveis substitutos a essas substâncias por serem menos tóxicos. O silano é um composto organofuncional que atua como agente de acoplamento entre superfícies orgânicas e inorgânicas, bem como pode fornecer proteção contra a corrosão. O objetivo deste trabalho é avaliar a resistência à corrosão do aço galvanizado tratado com filme de silano viniltrietoxisilano (VS) nas condições de hidrólise: concentração de silano (2%, 3% e 4% de silano) e tempo de hidrólise da solução (30 min, 45 min e 60 min), mantendo fixos o pH 4,0 da solução solvente água/etanol (50% v/v), a temperatura de cura (150ºC) e o tempo de cura (120 min). A resistência à corrosão do aço galvanizado tratado com filme de silano VS foi avaliada através de técnicas eletroquímicas como potencial de circuito aberto, espectroscopia de impedância eletroquímica (EIE), resistência à polarização linear (Rp) e curvas de polarização potenciodinâmicas em solução de NaCl 0,1 mol.L-1.A resistência à corrosão do aço galvanizado tratado com filme de silano VS foi avaliada através das seguintes técnicas eletroquímicas: potencial de circuito aberto (OCP), espectroscopia de impedância eletroquímica (EIE), resistência à polarização linear (Rp) e curvas de polarização potenciodinâmicas em solução de NaCl 0,1 mol.L-1. A caracterização química dos filmes foi feita através da técnica de espectroscopia na região do infravermelho (IR). A caracterização morfológica do aço galvanizado tratado foi analisada por microscopia eletrônica de varredura (MEV) e espectroscopia de dispersão de energia de raios X (EDS). Os resultados obtidos para as condições estudadas mostraram a formação de um filme eficiente na proteção contra a corrosão quando o aço galvanizado é pré-tratado com filme obtido na concentração de 4% de silano e 60 min de tempo de hidrólise. Os resultados eletroquímicos indicaram a formação de um filme eficiente na proteção contra a corrosão quando o aço galvanizado é tratado com filme obtido na concentração de 4% de silano e 60 min de tempo de hidrólise. As imagens de MEV revelaram uma menor formação de produto de corrosão quando o aço galvanizado é tratado com o filme de silano e os espectros de EDS apresentaram picos de Si indicando a aderência do filme no superfície do aço galvanizado. Já os espectros na região do IR apresentaram bandas de compostos contendo Si o que revelam a presença do filme de silano na superfície do substrato.

ABSTRACT Galvanized steel is obtained by immersing the carbon steel in a molten zinc bath widely employed in the automotive, petrochemical, chemical, marine, aeronautical and white-good appliances. It has higher corrosion resistance than carbon steel when exposed to corrosive environments. To increase its durability and corrosion resistance, it undergoes a surface treatment that is adherent to its surface. For this reason, phosphatization and chromatization are currently used as an after treatment to galvanization, both with environmental restrictions and human health. Due to the presence of toxic and carcinogenic products – in the chromatization or phosphatization - and to minimize the impact on the environment, the development of silane films as alternative pretreatments have been studied due to their good physical barrier properties against diffusion of oxygen to the metal interface and improve corrosion resistance. The aim of this work is to evaluate a corrosion resistance performance of galvanized steel coated with vinyltriethoxysilane (VS) film under hydrolysis conditions: silane concentration (2%, 3% and 4% %v) and hydrolysis time (30 min, 45 min and 60 min). The fixed variables were: the solvent solution used was water/ethanol (50% v/v) at pH 4.0, the curing time of 120 min and the curing temperature of 150°C in an oven. The corrosion resistance of pre-treated galvanized steel with VS silane film was evaluated by the following electrochemical techniques: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), linear polarization resistance (Rp) and potentiodynamic polarization curves in 0.1 mol.L-1 NaCl solution. The chemical properties of films were analyzed by infrared spectroscopy technique (IR). The galvanized steel and the film surface morphology were observed by scanning electron microscopy (SEM) and X-ray energy dispersion spectroscopy (EDX). The electrochemical results indicated the formation of an efficient corrosion protection film when galvanized steel is treated with film obtained at 4% silane concentration and 60 min hydrolysis time. SEM images revealed less corrosion product formation when galvanized steel is treated with silane film and EDS spectra showed Si peaks indicating the adhesion of the film to the galvanized steel surface. The spectra in the IR region showed bands of Si-containing compounds that reveal the presence of silane film on the substrate surface.

ABSTRACT In this work, the wettability of the galvannealed surface pretreated with the hybrid silane APTES/GPTMS film was measured by sessile drop method. The coatings were applied on the substrate from dip-coating method and dried in an oven. The study followed an experimental factorial design, 3³, with contact angle as response. The corrosion resistance was evaluated by electrochemical techniques and the surface morphology was characterized by scanning electron microscopy. The wettability results showed the best condition for galvannealed steel pretreated with the hybrid silane film for 2:1 APTES:GPTMS ratio, 2% silane concentration and 150 min of hydrolysis time, because the result may be related to a higher rate of hydrolysis of the silanes that is influenced by both the functional group present and by the type and number of hydrolyzed groups, resulting consequently in a higher availability of silanol groups in solution, promoting a greater crosslinking of the film on the metallic substrate.

RESUMO Silanos são compostos organo funcionais utilizados como agentes de acoplamentos entre interfaces orgânicoinorgânicas, com boas propriedades de adesão. Por esta razão, o uso de silanos como pré-tratamento para aços, vem ganhando espaço já que também são geradores de resíduos de menor toxidade ao meio ambiente e à saúde humana. Para melhorar a barreira de proteção do filme de silano e conferir propriedades de autorreparação, esses filmes podem ser modificados com íons cério. Assim, esse trabalho tem como objetivo avaliar a resistência à corrosão do filme de silanoviniltrimetoxisilano (VTMOS) modificado com íons Ce(III) ou íons Ce(IV) aplicado em aço carbono, utilizando a espectroscopia de impedância eletroquímica (EIE), técnica de varredura por eletrodo vibratório (Scanning Vibrating Electrode Technique -SVET), microscopia eletrônica de varredura (MEV) e transformada de Fourier de espectroscopia na região do infravermelho (Fourier Transform Infrared Spectroscopy -FTIR). Os resultados mostraram que os filmes com adição de íons Ce(IV) apresentaram uma melhor resistência à corrosão se comparados aos filmes com íons Ce(III), isto porque o filme formado com a adição de íons Ce(IV) mostrou um melhor efeito barreira devido à uma maior reticulação do filme.

ABSTRACT Silanes are organo functional compounds used as coupling agents between organic-inorganic interfaces, with good adhesion properties. For this reason, the use of silanes as pre-treatment for carbon steel is becoming more and more applicable , since they are also generators of less toxicity residues to the environmental and human health. In order to improve the barrier protection of the silane film and confer self-healing properties, these films can be modified by addition of cerium ions. Thus, these work aims to evaluate the corrosion resistance of vinythrimethoxysilane (VTMOS) film modified with Ce(III) ions or Ce(IV) ions for carbon steel, using the electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that Ce(IV) ions addition improved better corrosion resistance than the films with Ce(III) ions. The higher barrier effect is since the film formed in the presence of Ce(IV) ions is better reticulated.

Corrosion represents high losses to the economy, therefore, researches on the minimization of its damages in materials, mainly the metallic ones, are necessary. Among the various alternatives of protection against corrosion, there is the application of corrosion inhibitors that can minimize or even stop the corrosive process of metallic materials. However, at present, substances usually used as corrosion inhibitors present high toxicity, being considered harmful components to the environment and to human health. Therefore, there is an urgent need for studies on viable corrosion inhibitors, by considering not only economic but also environmental costs. The present work studied the use of cocoa bark extract (Theobrama cacao L), for possible replacement of benzotriazole (BTAH) in the corrosion inhibition of ASTM 1020 carbon steel (CS- ASTM 1020) in 18.23 g.L-1 hydrochloric acid media. Weight loss measurements, anodic and cathodic potentiodynamic polarization curves and electrochemical impedance experiments were carried out. The results showed that the addition of the extract to the electrolyte effectively hinder the corrosion process and indicated its adsorption on the electrode surface. In addition, the inhibiting efficiency of the cocoa bark extract was only slightly inferior to BTAH, showing that it can be an environmentally friendly option to toxic inhibitors.

ABSTRACT Metallic corrosion can be delayed using corrosion inhibitors. However, several industrial corrosion inhibitors are toxic and harmful to the environment and to the human health. In this context, in the last decades, research has been developed to investigate the performance of low toxicity corrosion inhibitors as green inhibitors obtained from vegetables, which are environmentally acceptable. The present work studied the corrosion inhibition efficiency of peel garlic extract (Allium sativum. L.) for possible replacement of benzotriazole (BTAH) on the corrosion inhibition of ASTM 1020 carbon steel (CS-1020) in 0.5 mol. L−1 hydrochloric acid media. Weight loss measurements, anodic and cathodic potentiodynamic curves and electrochemical impedance (EIS) experiments were carried out. The Fourier transformed infrared spectroscopy (FTIR) was carried out to evaluate the chemical compounds. The morphological characterization was obtained to observe the inhibitor effect in the corrosion products on substrate surface. The results showed that the addition of both inhibitors effectively hinder the corrosion process and indicated their adsorption on the electrode surface. The inhibiting efficiency of the peel garlic extract was only slightly inferior to BTAH showing that the former inhibitor can be an environmentally friendly option to toxic inhibitors. The FTIR analysis showed the presence of chemical compounds which presents antioxidant properties.

The inhibition effect of castor bark powder obtained from Ricinus communis on AISI 1020 carbon steel in acidic media (HCl 0.5 mol.L-1) has been studied by electrochemical impedance spectroscopy (EIS), polarization curves, scanning vibrating electrode technique (SVET) and weight loss measurements. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed as characterization techniques. The EIS and gravimetric results showed that the inhibitory efficiency increases with inhibitor concentration achieving 83%. Polarization curves indicated that the castor bark powder acts as mixed inhibitor. The adsorption of the powder components on the metal surface follows the Langmuir isotherm. The FTIR analyses indicate the presence of C, N and O heteroatoms, incorporated in functional groups mainly related to the presence of carboxylic acids as ricinoleic acid, which could be responsible for the inhibitory properties of the powder. SEM analyses showed that the corrosion process was retarded in the presence of inhibitor in the electrolyte, which was confirmed by SVET measurements. Therefore, the results indicate that castor bark powder has potential to be a corrosion inhibitor for carbon steel in acidic media.

El objetivo de este trabajo es presentar el desarrollo del software que permite el cálculo de la profundidad de carbonatación de los hormigones obtenidos mediante cementantes tales como Portland, escorias activadas alcalinamente (100%), y las mezclas obtenidas a partir de la adición de materiales puzolánicos como el humo de sílice, el metacaolín, cenizas volantes, entre otros. El software hace el cálculo de la profundidad de carbonatación por medio de dos ecuaciones. La primera ecuación utiliza el modelo matemático general de todos los procesos físico-químicos que intervienen en la carbonatación del hormigón y la segunda ecuación utiliza la cantidad de cementante y la reacción puzolánica de los materiales cementicios.

The aim of this paper is to bring forward a software development which allows the calculation of the carbonation depth of concrete obtained by cementing such as Portland, alkali activated slag (100%) and the mixtures obtained from the addition of pozzolanic materials such as silica fume, metakaolin, fly ash, etc. The calculation of the carbonation depth of concrete is made by the software using two different equations. The first equation uses general mathematical model of all physical and chemical processes that involved in concrete carbonation and the second equation uses the amount of cementitious and pozzolanic reaction of cementitious materials.

Este estudo focaliza o comportamento do aço galvanizado em um ambiente marinho corrosivo e no processo de escoamento superficial para o mesmo material que ocorrem em Valparaíso, Chile. O potencial de corrosão e a taxa de corrosão avaliados através de perda de massa foram utilizados para determinar os danos da corrosão para o aço galvanizado. As composições dos produtos de corrosão foram determinadas utilizando difratometria de raios X (XRD) e sua morfologia através da microscopia eletrônica de varredura (SEM). As soluções de escoamento coletadas após as chuvas foram analisadas para determinar o valor de pH e das concentrações dos íons Cl-, SO4(2 -) e Zn2+. Os resultados após 15 meses mostram que o potencial de corrosão do aço galvanizado aumenta ao longo do tempo, indicando a formação de uma película protetora que consiste em produtos de corrosão de zinco. Estes produtos foram identificados como zincita e simoncoleita. Os valores de pH obtidos para as soluções de escoamento são semelhantes das amostras de água da chuva de referência, e as concentrações de cloreto das soluções de escoamento são aproximadamente duas vezes as da água de chuva

This study focuses on the behavior of galvanized steel in a corrosive marine environment and on the runoff process for the same material occurring in Valparaiso, Chile. The corrosion potential and corrosion rate evaluated via mass loss were used to determine the corrosion damage to the galvanized steel. The compositions of the corrosion products were determined using X-ray diffractometry (XRD), and their morphology through scanning electron microscopy (SEM). The runoff solutions collected after rainfall were analyzed to determine the pH value, and Cl-, SO4(2 -) and Zn2+ ion concentrations. The results after 15 months show that the corrosion potential of the galvanized steel increases over time, indicating the formation of a protective film that consists of zinc corrosion products. These products were identified as zincite and simonkolleite. The pH values obtained for the runoff solutions are similar to those of the reference rainwater samples, and the chloride concentrations of the runoff solutions are approximately twice those of the rainwater.

En el presente trabajo se presentan los resultados preliminares obtenidos para la construcción del mapa de corrosión atmosférica de Chile, evaluando acero al carbono, acero galvanizado, cobre y aluminio como materiales de prueba. Se instalaron bastidores con las muestras en 31 lugares localizados a lo largo del país, así como también dispositivos para medir el contenido de cloruro y dióxido de azufre ambiental, en conjunto con estaciones meteorológicas, para obtener los datos locales de temperatura, humedad ambiental, cantidad de agua caída, velocidad y dirección de los vientos y radiación solar. Los resultados después de 6 meses de exposición muestran una relación entre la velocidad de corrosión, las condiciones ambientales y meteorológicas de la zona y las propiedades mecánicas de los materiales, lo que constituye una importante innovación para las empresas del país que esperan que sus estructuras metálicas logren un mayor tiempo de vida útil.

This work show the first part of a research project towards the development of a corrosion map for Chile. In order to develop this map, the research group considered carbon steel, galvanized carbon steel, copper and aluminum as testing materials. All these materials were exposed to the atmosphere in 31 places along the country. In each one of these corrosion testing sites, the metallic samples were mounted on frameworks. Each framework station had chloride and sulfur dioxide meters as well as a weather station, to measure temperature, environmental humidity, rainfall, wind speed and solar radiation. After six months of exposition, the results show the existence of a correlation between the rate of corrosion, the environmental and meteorological conditions of the area and the mechanical properties of the materials. This information constitutes an important tool of innovation for the industries in Chile, because the obtained information will be helpful to design metallic infrastructure with a longer useful live.