A determination of corrosion inhibitors in engine coolants represent a difficult analytical problem due to their different physicochemical properties. Nowadays a lot of instrument methods are needed to determine them. The aim of this work was the development of methods for their determination using only one instrumentation. Capillary zone electrophoreses was chosen as a suitable technique. Three electrophoretic methods for three groups of corrosion inhibitors were developed. Firstly, method for determination of inorganic anions was developed in range from 5 to 50 ppm with limit of detection around 1 ppm. Background electrolyte contains sodium chromate, CTAB and CHES solution. Analytes were detected indirectly at 450 nm. Another method was for determination of organic acids anions. They were determined in range from 5 to 500 ppm. Limit of detection for each analyte was around 1 ppm. Measurement was made with PDC a CTAC water solution. Indirect detection was used for this determination at 350 nm. Last developed method can be use for determination of aryltrizoles in range from 5 to 500 ppm. Limit of detection was around 1 ppm. As a background electrolyte was used sodium tetraborate solution. The developed methods were validated and their suitability for determination of corrosion inhibitors in real...

O objetivo deste trabalho foi formular e otimizar uma mistura de quatro substâncias atóxicas como inibidores de corrosão para o aço carbono ABNT 1005 em meio de água de resfriamento industrial. As substâncias estudadas foram o molibdato de sódio, o tungstato de sódio, a ftalocianina de cobre e um tensoativo polimérico a base de silano de peso molecular 17.000 g.mol-1. As técnicas usadas neste estudo foram medidas de potencial de corrosão, espectroscopia de impedância eletroquímica e curva de polarização anódicas e catódicas. O tratamento dos resultados de espectroscopia de impedância eletroquímica foi feito por meio da modelagem com circuitos elétricos equivalentes, que permitiu quantificar parâmetros como resistência a transferência e carga (Rtc) e capacitância dupla camada elétrica, (Cdl). Para caracterizar a superfície do metal foram obtidas imagens por microscopia eletrônica de varredura, onde foi comprovada a alteração da superfície pela presença das substâncias estudadas. Pelas curvas de polarização foi verificado que todas as substâncias estudadas se comportam como inibidores de corrosão anódicos no meio estudado, isto é, diminuem a velocidade de dissolução do metal na presença de maiores concentrações. O uso de um projeto fatorial completo, do tipo 24 foi decisivo para identificar os principais efeitos e interações entre as substâncias; sendo que os mais importantes foram devidos à presença de molibdato e tungstato de sódio, ou seja, a presença destas duas substâncias aumentou a resistência à transferência de carga do aço carbono no meio estudado. Em seguida, a análise estatística do projeto fatorial composto permitiu estimar a concentração ótima para a mistura de molibdato e tungstato de sódio; como o ponto de máximo da função superfície de resposta obtida. A concentração ótima estimada de molibdato e de tungstato de sódio foi de 3,6 x10-3M e 3,5x10-3M respectivamente. Finalmente, foi feita a avaliação ao longo de um período de tempo de 88 horas que permitiu identificar que o melhor comportamento da Rtc e da Cdl foi entre 48 e 72 horas de imersão. / The aim of this investigation is to obtain the optimum formulation of four nontoxics substances tested as corrosion inhibitors for ABNT 1005 carbon steel in watercooling systems. The studied substances were: sodium molybdate, sodium tungstate, copper phthalocyanine and a modified copolymer of polyoxialkylene and polidimethysiloxane. Electrochemical techniques as corrosion potential, impedance spectroscopy (EIS) and potenciodynamic anodic and cathodic polarization curves were used. Electrochemical impedance spectroscopy results were fitted through equivalent electric circuit modeling that allowed quantifying parameters like: the charge transfer resistance (Rtc) and double layer capacitance (Cdl) among others. In order to characterize the metal surface, scanning electronic microscopy images were obtained. These images allowed to evidence the surface alteration resulted from the addition of the studied inhibitors. Using polarization curves were verified that all substances studied behave as anodic corrosion inhibitors, this is, metal dissolution rate decrease when higher inhibitors concentrations were added. By applying a 24 design of experiments (DOE) were possible to identify the main effects and interactions between the substances (entry variables) on the charge transfer resistance (response variable). The main effects and interactions were obtained due to the presence of sodium molybdate and sodium tungstate; the Rtc got higher values as result of the presence of sodium molybdate and sodium tungstate. As a next step, using a design of experiments with central point was allowed to estimate the optimum concentration of sodium molybdate and sodium tungstate as result of the maximum of response surface obtained from statistic analysis in a wider range of concentrations. The optimum concentration estimated was 3,6x10-3M and 3,5x10-3M from sodium molybdate and sodium tungstate respectively. Finally it was done an immersion time evaluation until 88 hours using the optimum inhibitors concentration; the best performance of de Rtc and Cdl were between 48 and 72 hours of immersion.

The present work provides an insight in the development of silica films prepared by water-based sol-gel process. The weaknesses of the coating technology are identified, also solutions are discussed. The silica film is applied on aluminium alloy 6082-T6 and magnesium alloy AZ31. The development of the coating properties such as cost-efficiency, crack-free, self-healing and long-term corrosion protection is the main topic of this work. Cracking is the major drawback of silica films; the cracks are generated due to shrinkage of the film during the heat treatment, nanoparticles-doped silica film is successfully reduced the shrinkage which leads to crack-free silica films. The self-healing of the coated aluminium and magnesium samples is generated by corrosion inhibitors-doped silica film. When a defect appears in the film, the corrosion inhibitors leach out of the silica film to the defect area to heal the corroded surface. The long-term corrosion protection is realized by means of a mixture of corrosion inhibitors-doped silica film. / Die vorliegende Arbeit liefert einen Einblick in die Entwicklung von Silikafilmen, die mittels Sol-Gel-Prozess auf Wasserbasis hergestellt wurden. Die Schwächen der Beschichtungstechnologie werden dargestellt und Lösungen diskutiert. Der Silikafilm wird auf Aluminiumlegierung 6082-T6 und Magnesium-legierung AZ31 aufgebracht. Schwerpunkt dieser Arbeit ist die Entwicklung der Schichteigenschaften, wie Kosteneffizienz, Rissfreiheit, Selbstheilung so wie langfristiger Korrosionsschutz. Rissbildung ist ein wesentlicher Nachteil von Silikafilmen; rissfreie Filme wurden mittels nanopartikeldotierter Silikafilme hergestellt. Die Selbstheilung von Aluminium-und Magnesiumsubstraten mit Silikafilm wird durch den Effekt der wasserlöslichen Korrosionsinhibitoren generiert. Die Experimente haben gezeigt, dass die Proben mit inhibitordotierter Beschichtung selbst gegen Korrosion geschützt sind. Ein langfristiger Korrosionsschutz wird durch eine Mischung aus Korrosionsinhibitor-dotierten Silika-Film realisiert.

Υπάρχει ένα συνεχές ενδιαφέρον για τη σύνθεση και το χαρακτηρισμό συμπλόκων των μετάλλων μετάπτωσης (μεταβατικών μετάλλων) με υποκαταστάτες βενζοτριαζολικού τύπου. Το ενδιαφέρον αυτό οφείλεται κυρίως στην αντιδιαβρωτική δραστικότητα του βενζοτριαζολίου (btaH) έναντι ορισμένων μετάλλων κυρίως του Cu και των κραμάτων του. Οι μοριακοί μηχανισμοί της παρεμπόδισης της διάβρωσης των μετάλλων από τα βενζοτριαζόλια δεν έχουν διερευνηθεί πλήρως. Στην παρούσα Διπλωματική Εργασία αναπτύσσεται ένα μοντέλο της παρεμπόδισης της διάβρωσης του Fe από το btaH με τη χρησιμοποίηση ιδεών της Χημείας Ένταξης (Συναρμογής). Παρασκευάσθηκαν τα σύμπλοκα [FeCl3(Mebta)2] (1), [FeCl3(btaH)2] (2), (Et3NH)[Fe14O9(OMe)9Cl9(bta)7(MeOH)2(H2O)2] (3), [FeCl3(5ClbtaH)2].2(5ClbtaH) (4), [FeCl3(5,6dimebtaH)2] (5), [FeBr3(btaH)2] (6), [Fe14O8(OH)(OMe)9Br9(bta)7(MeOH)2(H2O)2].2MeOH (7.2MeOH) και {(5ClbtaH)2H}[FeBr4] (8), όπου Mebta = 1- μεθυλοβενζοτριαζόλιο, 5ClbtaH = 5-χλωροβενζοτριαζόλιο και 5,6dimebtaH = 5,6-διμεθυλοβενζοτριαζόλιο. Τα σύμπλοκα χαρακτηρίσθηκαν με μικροαναλύσεις και φασματοσκοπία IR. Οι μοριακές και κρυσταλλικές δομές των ενώσεων προσδιορίσθηκαν με κρυσταλλογραφία ακτίνων Χ επί μονοκρυστάλλων. Τα σύμπλοκα 1, 2 και 4-6 είναι μονοπυρηνικά με πέντε μονοδοντικούς υποκαταστάτες (τρεις αλόγονο, δύο Ν-δότες). Το ιόν FeIII βρίσκεται σε ένα τριγωνικό διπυραμιδικό περιβάλλον ένταξης με τους τρεις αλόγονο υποκαταστάτες να ορίζουν το ισημερινό επίπεδο. Η ένωση 8 είναι ιοντική, περιλαμβάνοντας το πρωτότυπο κατιόν {(5ClbtaH)2H}+ και το τετραεδρικό ανιόν [FeBr4]-. Το πολυπυρηνικό ανιόν της πλειάδας 3 συγκρατείται μέσω έξι μ3-O2-, τριών μ4-O2-, εννέα μ2-OMe-, πέντε η1:η1:η1:μ3 bta- και δύο η1:η1:μ2 bta- υποκαταστατών. Η περιφερειακή ένταξη συμπληρώνεται από εννέα Cl-, δύο MeOH και δύο H2O με τους τρεις αυτούς υποκαταστάτες να είναι τερματικοί. Τα κέντρα FeIII υιοθετούν τρεις διαφορετικές γεωμετρίες ένταξης (οκταεδρική, τριγωνική διπυραμιδική, τετραεδρική). Τα δεκατέσσερα κέντρα FeIII ορίζουν μια εξαεπιστεγασμένη εξαγωνική διπυραμίδα. Το πολυπυρηνικό μόριο της ένωσης 7.2MeOH έχει παρόμοια δομή με αυτήν του ανιόντος του 3, με έναν μ3-O2- υποκαταστάτη του 3 να έχει αντικατασταθεί από έναν και μοναδικό μ3-OH- υποκαταστάτη στην 7.2MeOH. Οι δεκατετραπυρηνικές πλειάδες 3 και 7.2MeOH μπορούν να θεωρηθούν ως μοντέλα της παρεμπόδισης της διάβρωσης του Fe σε ουδέτερα pH, ενώ η κρυσταλλική δομή της ένωσης 8 δίνει μια ένδειξη σχετικά με το μοριακό μηχανισμό των αντιδιαβρωτικών ιδιοτήτων επιλεγμένων βενζοτριαζολίων έναντι του σιδήρου σε όξινα pH. Τα σύμπλοκα 2 και 4 αποτελούν αποτελεσματικούς ομογενείς καταλύτες σε αντιδράσεις οξείδωσης αλκανίων και αλκενίων με το “πράσινο” οξειδωτικό H2O2. Η παρούσα εργασία μπορεί επίσης να θεωρηθεί ως μια συνεισφορά στη χημεία ένταξης των βενζοτριαζολίων και στη χημεία των πλειάδων του FeIII. / There is continuing interest in the synthesis and characterization of transition metal complexes with benzotriazole ligands. This is primarily due to the anticorrosion activity of benzotriazole (btaH) towards certain metals, particularly Cu and its alloys. The molecular mechanisms for the corrosion inhibition of metals by benzotriazoles have not been completely elucidated. An inorganic chemistry model approach to the corrosion inhibition of Fe by btaH has been developed in the present Diploma Thesis. Complexes [FeCl3(Mebta)2] (1), [FeCl3(btaH)2] (2), (Et3NH)[Fe14O9(OMe)9Cl9(bta)7(MeOH)2(H2O)2] (3), [FeCl3(5ClbtaH)2].2(5ClbtaH) (4), [FeCl3(5,6dimebtaH)2] (5), [FeBr3(btaH)2] (6), [Fe14O8(OH)(OMe)9Br9(bta)7(MeOH)2(H2O)2].2MeOH (7.2MeOH) and {(5ClbtaH)2H}[FeBr4] (8), where Mebta = 1- methylbenzotriazole, 5ClbtaH = 5-chlorobenzotriazole and 5,6dimebtaH = 5,6-dimethylbenzotriazole, have been prepared. The complexes have been characterized using microanalyses and IR spectroscopy. The molecular and crystal structures of the compounds have been determined by single-crystal X-ray crystallography. Complexes 1, 2 and 4-6 are mononuclear with five monodentate ligands (three halogenido, two N-donors). The FeIII ion is in a trigonal bipyramidal coordination environment with the three halogenido ligands defining the equatorial plane. Compound 8 is ionic, containing the novel {(5ClbtaH)2H}+ cation and the tetrahedral [FeBr4]- ion. The cluster anion of 3 is held together by six κ3-O2-, three κ4-O2-, nine κ2-OMe-, five ε1:ε1:ε1:κ3 bta- and two ε1:ε1:κ2 bta- ligands. Peripheral ligation is completed by nine Cl-, two MeOH and two H2O terminal ligands. The FeIII centers adopt three different coordination geometries (octahedral, trigonal bipyramidal, tetrahedral). The 14 FeIII centers define a hexacapped hexagonal bipyramid. The cluster molecule of 7.2MeOH has a similar structure; one κ3-O2- of 3 has been replaced by a unique κ3-OH- in 7.2MeOH. The tetradecanuclear clusters 3 and 7.2MeOH may be considered as models for the corrosion inhibition of Fe by benzotriazoles at neutral pHs, while the crystal structure of 8 gives a clue for the molecular mechanism of the anticorrosion properties of selected benzotriazoles towards iron at acidic pHs. Complexes 2 and 4 are effective homogeneous catalysts for alkane and alkene oxidations with the eco-friendly oxidant H2O2. iv The present work can be also considered as a contribution in the coordination chemistry of benzotriazoles and in the cluster chemistry of FeIII.

Made available in DSpace on 2014-12-17T14:07:04Z (GMT). No. of bitstreams: 1 CassiaCA_DISSERT.pdf: 2177170 bytes, checksum: cdd70e45de9bf16e746160bcfa2059cf (MD5) Previous issue date: 2012-10-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In general, among the corrosion inhibitors surfactants are the most commonly used compounds, because they are significantly effective by forming protective films on anodic and cathodic areas. In this study, microemulsions containing he biodegradable saponified coconut oil as surfactant (SME-OCS) was used as green corrosion inhibitors. With this purpose, methanolic extracts of Ixora coccinea Linn (IC) and a polar fraction rich in alkaloids (FA) obtained from Croton cajucara Benth solubilized in the SME-OCS system were examined in the presence of AISI 1020 carbon steel, in saline solution (NaCl 3,5 %). The efficiency of corrosion inhibition of IC and FA were evaluated in the following microemulsions: SME-OCS-IC and SME-OCS-FA. The microemulsion system SME-OCS in the presence and absence of IC and FA was assessed by measurements of weight loss and the electrochemical method of polarization resistance, with variation in the concentration of IC and FA (50 - 400 ppm), showing significant results of corrosion inhibition (83,6 % SME-OCS; 92,2 % SME-OCS-FA; and 95,3 % SME-OCS-IC) / Em linhas gerais, dentre os inibidores de corros?o mais utilizados se encontram os tensoativos, que s?o significantemente eficazes por formarem pel?culas protetoras sobre ?reas an?dicas e cat?dicas. No presente trabalho, utilizou-se o tensoativo biodegrad?vel ?leo de coco saponificado microemulsionado (SME-OCS) para aplicabilidade como inibidor verde de corros?o. Para tanto, o extrato metan?lico de Ixora coccinea Linn (IC) e uma fra??o polar rica em alcaloides (FA) obtida de Croton cajucara Benth, solubilizados no sistema SME-OCS, foram avaliados na presen?a do a?o carbono AISI 1020, em meio salino (NaCl 3,5 %). Desta forma, as efici?ncias de inibi??es ? corros?o de IC e FA foram avaliadas nas seguintes microemuls?es: SME-OCS-IC e SME-OCS-FA. O sistema microemulsionado SME-OCS na presen?a e na aus?ncia de IC e FA foi avaliado por medidas de perda de massa e pelo m?todo eletroqu?mico de resist?ncia ? polariza??o, com varia??o da concentra??o dos vegetais IC e FA (50 400 ppm), tendo sido obtidos resultados significativos de inibi??es ? corros?o (83,6 % SME-OCS, 92,2 % SME-OCS-FA e 95,3 % SME-OCS-IC)

Made available in DSpace on 2016-12-08T17:19:21Z (GMT). No. of bitstreams: 1 Luiz Fernando Giacchero.pdf: 4189596 bytes, checksum: 744ba5d6d712d7bbaf8643e411becaf4 (MD5) Previous issue date: 2013-07-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In order to know the electrochemical behavior of galvanized steel and improve its corrosion protection were tested mineral oils and emulsions which exist in the industrial sector in order to compare the electrochemical tests with results obtained in natural tests. The galvanizing Industries care about a safety when selling their material and the mineral oils inhibitors are widely used in this field, but if these oils or oil-water emulsions are not in the ideal concentration, they can not ensure protection for galvanized steel, which is usually required by suppliers of at least six months without the formation of corrosion products. The technique of electrochemical impedance spectroscopy (EIS) and polarization curves anodic and cathodic (CPOL) showed the electrochemical behavior of galvanized steel, ordinary steel, the electrochemical behavior of galvanized steel in the presence of mineral oils and emulsifying behavior even in presence of oil full. Immersion tests were performed at regular steel and galvanized steel in order to understand the mechanisms of formation of corrosion products and the results were obtained by scanning electron microscopes (SEM) techniques and X-ray diffraction (XRD). Tests were also conducted with natural samples of galvanized steel with different concentrations of oil in an airtight container with the atmosphere of a more aggressive galvanizing industry partner in this research for a period of six months at the most critical period of the year where the great heat exchange causes a greater number of cycles that dry and wet samples favoring the formation of corrosion products. Samples will be collected after the six-month period and analyzed by SEM and XRD to identify the corrosion products formed comparing the analyzes obtained for several concentrations of emulsions and thus identifying the most efficient way to ensure the protection against corrosion in galvanized steel. / As indústrias de galvanização que armazenam o aço zincado em locais de alta umidade relativa propiciam a formação da corrosão branca que afeta a estética e, conseqüentemente, a comercialização do material. Para zelar pela integridade do metal, óleos minerais são utilizados neste campo como inibidores temporários de corrosão. Porém, se esses óleos ou emulsões óleo-água não estiverem na concentração ideal, poderão não garantir uma proteção para o aço zincado, que costuma ser exigida por fornecedores de no mínimo seis meses sem a formação de produtos de corrosão visíveis a olho nu. A técnica de espectroscopia de impedância eletroquímica (EIE) e as curvas de polarização anódicas e catódicas (Cpol) mostraram o comportamento eletroquímico do aço galvanizado, aço comum, aço galvanizado em presença de óleos minerais emulsionáveis e o comportamento desse em presença de óleo integral. Ensaios de imersão foram realizados no aço comum e galvanizado a fim de conhecer os produtos de corrosão por microscopia eletrônica de varredura (MEV) e por difração de raios X (DRX). Ensaios naturais também foram realizados com amostras de aço galvanizado com diferentes concentrações de óleo num recipiente hermeticamente fechado com a atmosfera de uma indústria parceira do setor por um prazo de seis meses no período mais crítico do ano onde a grande inversão térmica provoca um maior número de ciclos de secagem favorecendo a formação de produtos de corrosão. As amostras com concentração abaixo de 15% revelaram produtos comuns aos ensaios de imersão como os hidroxicloretos hidratados de zinco nas amostras com emulsões de concentração de 5% de óleo e os hidroxicarbonatos de zinco nas placas com concentração de 5% e 10% de óleo, sendo apenas as emulsões com teor de óleo igual ou maior a 15% eficientes neste período de tempo.

O objetivo deste trabalho foi formular e otimizar uma mistura de quatro substâncias atóxicas como inibidores de corrosão para o aço carbono ABNT 1005 em meio de água de resfriamento industrial. As substâncias estudadas foram o molibdato de sódio, o tungstato de sódio, a ftalocianina de cobre e um tensoativo polimérico a base de silano de peso molecular 17.000 g.mol-1. As técnicas usadas neste estudo foram medidas de potencial de corrosão, espectroscopia de impedância eletroquímica e curva de polarização anódicas e catódicas. O tratamento dos resultados de espectroscopia de impedância eletroquímica foi feito por meio da modelagem com circuitos elétricos equivalentes, que permitiu quantificar parâmetros como resistência a transferência e carga (Rtc) e capacitância dupla camada elétrica, (Cdl). Para caracterizar a superfície do metal foram obtidas imagens por microscopia eletrônica de varredura, onde foi comprovada a alteração da superfície pela presença das substâncias estudadas. Pelas curvas de polarização foi verificado que todas as substâncias estudadas se comportam como inibidores de corrosão anódicos no meio estudado, isto é, diminuem a velocidade de dissolução do metal na presença de maiores concentrações. O uso de um projeto fatorial completo, do tipo 24 foi decisivo para identificar os principais efeitos e interações entre as substâncias; sendo que os mais importantes foram devidos à presença de molibdato e tungstato de sódio, ou seja, a presença destas duas substâncias aumentou a resistência à transferência de carga do aço carbono no meio estudado. Em seguida, a análise estatística do projeto fatorial composto permitiu estimar a concentração ótima para a mistura de molibdato e tungstato de sódio; como o ponto de máximo da função superfície de resposta obtida. A concentração ótima estimada de molibdato e de tungstato de sódio foi de 3,6 x10-3M e 3,5x10-3M respectivamente. Finalmente, foi feita a avaliação ao longo de um período de tempo de 88 horas que permitiu identificar que o melhor comportamento da Rtc e da Cdl foi entre 48 e 72 horas de imersão. / The aim of this investigation is to obtain the optimum formulation of four nontoxics substances tested as corrosion inhibitors for ABNT 1005 carbon steel in watercooling systems. The studied substances were: sodium molybdate, sodium tungstate, copper phthalocyanine and a modified copolymer of polyoxialkylene and polidimethysiloxane. Electrochemical techniques as corrosion potential, impedance spectroscopy (EIS) and potenciodynamic anodic and cathodic polarization curves were used. Electrochemical impedance spectroscopy results were fitted through equivalent electric circuit modeling that allowed quantifying parameters like: the charge transfer resistance (Rtc) and double layer capacitance (Cdl) among others. In order to characterize the metal surface, scanning electronic microscopy images were obtained. These images allowed to evidence the surface alteration resulted from the addition of the studied inhibitors. Using polarization curves were verified that all substances studied behave as anodic corrosion inhibitors, this is, metal dissolution rate decrease when higher inhibitors concentrations were added. By applying a 24 design of experiments (DOE) were possible to identify the main effects and interactions between the substances (entry variables) on the charge transfer resistance (response variable). The main effects and interactions were obtained due to the presence of sodium molybdate and sodium tungstate; the Rtc got higher values as result of the presence of sodium molybdate and sodium tungstate. As a next step, using a design of experiments with central point was allowed to estimate the optimum concentration of sodium molybdate and sodium tungstate as result of the maximum of response surface obtained from statistic analysis in a wider range of concentrations. The optimum concentration estimated was 3,6x10-3M and 3,5x10-3M from sodium molybdate and sodium tungstate respectively. Finally it was done an immersion time evaluation until 88 hours using the optimum inhibitors concentration; the best performance of de Rtc and Cdl were between 48 and 72 hours of immersion.

Orientador: David Mendez Soares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-06T09:05:00Z (GMT). No. of bitstreams: 1 Pinto_EdilsonMoura_M.pdf: 2421703 bytes, checksum: 4f88cfbf1bf972bc5ed1991a06982550 (MD5) Previous issue date: 2004 / Resumo: Neste trabalho, a QCM (Quartz Crystal Microbalan e) Microbalança de Cristal de Quartzo, como ténica alternativa para o estudo da corrosão /inibição do metal cobre. Estudamos a proteção anti-corrosão de superfícies de cobre mediante a adsorção de inibidores voláteis de corrosão (VCI-CHAB,Ciclohexilamina-Benzoato). Utilizamos uma QCM, composta de um cristal de quartzo de 6MHz, recoberto por um filme de ouro depositado por sputtering. Utilizamos Técnicas eletroquímicas para caracterizar a corrosão. Para isto, estudamos a corrosão do metal cobre em diferentes ambientes, básicos e ácidos, na presença e ausência dos inibidores. Aplicamos a QCM acoplada à um potenciostato (EQCM), como método de determinação de variação de massa e e carga de correntes da corrosão/inibição. A presença dos filmes VC I sobre a superfície de cobre, também foi demonstrada pela técnica Reflection-Absorption Infra-Red Spectros opy (RAIRS), através da Micros copia de infravermelho razante, esta técnica é indicada para situações em que os filmes formados são Ultra-finos. Baseado nos resultados das medidas feitas, propomos e des revemos um modelo para a dsorção dos filmes VCI sobre a superfície metálica, incluindo a formação da corrosão por pitting / Abstract: In this work we used the QCM (Quartz Crystal Microbalance) as an alternative technique for the studying of the corrosion/inhibition of cooper. We studied the protection of cooper surfaces due to the adsorption of a volatile corrosion inhibitor, (VCI-Cyclehexilamine-Benzoate). We used electrochemical techniques to characterize the corrosion in different environments. We applied the QCM together with the potentiostat as a method of determination of charge and mass variations. In this work the QCM has been used as a complementary technique for investigating the corrosion of copper with and without adsorbed inhibitors. The protection of copper surfaces due to the adsorption of a volatile corrosion inhibitor (VCI) ¿ Cyclohexylamine Benzoate ¿ has been studied by electro chemical techniques to characterise the corrosion in aqueous environments over a wide range of pH values. The presence of VCI films on the copper surface was also shown by Reflection-Absorption Infra-Red Spectroscopy (RAIRS), a technique indicated for situations when very thin films are formed. The EQCM, which used 6 MHz gold-sputtered quartz crystals coated with electrodeposited copper films, was applied to the simultaneous determination of the charge and frequency variations associated with the corrosion process, with and without adsorbed inhibitor. Based on the measurements, a model has been developed to describe the dynamics of adsorption of the VCI on the metalli surface, including the formation of pits on the surface / Mestrado / Superfícies e Interfaces ; Peliculas e Filamentos / Mestre em Física

This diploma thesis is focused on proposition of non-freezing heat transfer fluid for solar systems. Fluid will be based on mixture of new available compound propane-1,3-diol with water and modern corrosion inhibitors. Then will be investigate, if this new compound is competetive to common used liquids like ethylene glycol or propylene glycol.

This thesis is focused on proposition of non-freezing heat transfer fluid. Fluid will be based on mixture of propane-1,2,3-triol with water and modern corrosion inhibitors. Then will be investigate, if this new compound is competetive to common used liquids like ethylene glycol or propylene glycol.