The tinplate, used in the packaging sector and formed from a metal substrate, comprises a steel base which has undergone a surface treatment to produce a thin layer of FeSn2, a tin layer and an oxide tin layer. Currently, packaging using surface treatment is based on the use of chromates because these metals provide an excellent corrosion resistance. Nontoxic alternatives to pre-treatments have been developed in recent years to replace the chromate process. The aim of this work is to analyze the performance of a new hybrid organic-inorganic film obtained from sol-gel consisting of the alkoxide precursors 3-(Trimethoxysilylpropyl)methacrylate (TMSM) and tetraethoxysilane (TEOS) with the addition of cerium nitrate with the scanning vibrating electrode technique (SVET), and electrochemical and morphological characterizations. Moreover, the evolution of the corrosion of the substrate was evaluated to propose a mechanism of corrosion. The results showed a galvanic coupling between the Sn/SnO2 coat (cathode) and the defects exposed at the ferrous base (anode). The organic-inorganic hybrid film containing a cathodic corrosion inhibitor was able to retard the corrosion of the tinplate.

Among the applications for protic ionic liquids (PILs), lubrication is one of the newest and the most promising. In this work, ammonium-based protic ionic liquids were tested as lubricant fluids for aluminum-steel contacts. PILs were synthesized with 2-hydroxyethylamine (2HEA) and a carboxylic acid (formic and pentanoic), aiming to understand the effect of two different anion chain lengths on the lubricant behavior. The synthesized PILs were characterized by RMN, FTIR and TGA. Wear tests, conducted using a ball-on-plate configuration, showed that the increase of the anion carbon chain length in the PIL structure reduced significantly the coefficient of friction value. Besides, after the wear tests, the PILs structural integrity was not affected. In the same way, bending under tension (BUT) tests evidenced that the performance for stamping conditions of the PIL with the longest anion carbon chain was similar to that of the commercial lubricant. Since, both formed a uniform tribofilm, developed the same lubrication regime and the drawing forces values were close and constant. Hence, the ionic liquid obtained with 2HEA and pentanoic acid (2HEAPe) is as suitable as the commercial lubricant for metal forming processes.

Los materiales híbridos a base de siloxano y PMMA se constituyen por una red de silicona, a la que están enlazadas cadenas de polimetilmetacrilato. Su estabilidad y adherencia permiten su aplicación en láminas de estaño para aumentar la resistencia a la corrosión. En este trabajo se recubrió una lámina de estaño con una película híbrida a partir de un sol que consta de los precursores alcóxidos: 3-trimetoxisililpropilmetacrilato (TMSM) y polimetilmetacrilado (PMMA). Se evaluó la influencia de la adición de tetraetoxisilano (TEOS). Se evaluó la morfología de los filmes por SEM y ángulo de contacto. Se evaluó el comportamiento electroquímico con medidas de potencial a circuito abierto, polarización potenciodinámica e impedancia electroquímica. Los resultados muestran que la película con mayor adición de TEOS tuvo mayor espesor; sin embargo, el TEOS intensificó la densificación. Así, se formaron grietas que comprometieron la resistencia a la corrosión.

Siloxane - poly (methylmethacrylate)-based materials are systems formed by a silicon network, to which chains of poly (methylmethacrylate) are linked by covalent bonds or by physical interactions. Their stability and adherence allow their application on substrates like tin plate in order to increase the corrosion resistance. The aim of this work is to coat tin plate with a hybrid film obtained from a sol consisting of alkoxide precursors: 3 - (trimethoxysilylpropyl) methacrylate (TMSM) and poly (methyl methacrylate) PMMA. Effect of tetraethoxysilane (TEOS) addition was evaluated. Morphology was evaluated by SEM and contact angle. Electrochemical behavior was evaluated by open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Results showed that siloxane-PMMA film obtained with a higher addition of TEOS had higher thickness. However, intense densification caused by TEOS addition promoted crack formation, thereby compromising the corrosion resistance.

Titanium and its alloys have been widely used in implants and prostheses. However, the clinical success of these biomaterials can be compromised due to failures that can occurs by loss cohesion of tissue, fracture or allergic reactions caused by the presence of dissolved metallic ions or detached solid particles by mechanical factors. Some results presented on the literature have been showed that the surface roughness of the titanium implants affects the osseointegration rate and biomechanical fixation. The present work aims to study the current density effect on the electrochemical treatment of Ti to obtain nanostructured surfaces. The samples were mechanically sanded and electrochemical treatment on acid solution. After the electrochemical treatment the samples were characterized by atomic force microscopy, profilometry and wettability tests. Preliminary results showed that is possible to control the morphology of nanostructured surfaces by electrochemical treatment parameters control.

O emprego do titânio e outras ligas como implantes e próteses têm tido grande repercussão clínica nos últimos anos. No entanto, apesar do êxito clínico, esses biomateriais têm apresentado problemas devido a falhas que podem ocorrer pelo desgaste, fratura ou por reações alérgicas ocasionadas pela presença de íons metálicos dissolvidos ou partículas sólidas desprendidas do implante por fenômeno mecânico. Há inúmeros relatos na literatura demonstrando que a rugosidade da superfície de implantes de titânio afeta a taxa de osseointegração e fixação biomecânica. Nesse contexto, o presente trabalho tem por objetivo estudar o efeito da densidade de corrente no processo de tratamento eletroquímico do Ti visando à obtenção de superfícies nanoestruturadas. Para isso as amostras de Ti foram lixadas mecanicamente e submetidas um processo de tratamento eletroquímico em solução ácida. Nessa etapa do estudo variou-se a densidade de corrente, mantendo fixos os demais parâmetros. Após o processo de tratamento eletroquímico as amostras foram caracterizadas por microscopia de força atômica, perfilometria e ensaios de molhabilidade. Resultados preliminares mostraram que é possível controlar a morfologia de superfícies nanoestruturadas a partir do controle da densidade de corrente.

En el presente trabajo, se llevó a cabo un estudio de corrosión causada por distintos líquidos iónicos sobre placas de acero al carbón A285 grado A, a temperatura ambiente. Se prepararon los líquidos iónicos por neutralización de monoetanolamina con ácidos carboxílicos. El carácter hidrofílico o hidrofóbico de los líquidos se determinó a través de la técnica de humectabilidad. El análisis de corrosión se llevó a cabo por técnicas electroquímicas (potencial de circuito abierto y polarización potenciodinámica). Se realizó un análisis de la morfología del sustrato, antes y después de los análisis electroquímicos, por microscopía electrónica de barrido acoplada con espectroscopía de rayos X por dispersión de energía. Los resultados muestran pequeñas tasas de corrosión para el acero al carbono A285 grado A en contacto con los líquidos iónicos, de las cuales la superior se mostró con lactato de 2-hidroxietanolamina y la más baja con acetato de 2-hidroxietanolamina.

In this work, corrosion caused by different ionic liquids on Grade A - A285 carbon steel plates at room temperature (25°C) is studied. Ionic liquids were prepared via acid - base neutralization. The ionic liquid hydrophilic or hydrophobic character was determined by the wettability technique. Corrosion behavior for each system was analyzed by electrochemical measurements (open circuit potential monitoring and potentiodynamic polarization). Substrate morphology was analyzed by scanning electron microscope and energy dispersive X-ray spectroscopy before and after the electrochemical measurements. The results obtained showed that Grade A - A285 carbon steel in contact with the ionic liquids presented low corrosion rates, being the highest one the corresponding for the 2-hydroxyethylamominum lactate system and the lowest corrosion rate for 2-hydroxyethylammonium acetate system.

As indústrias galvânicas utilizam, durante o seu processo produtivo, vários tipos de soluções químicas, além de água, que, após o seu ciclo de vida, devem ser descartadas. Entre esses insumos, está o cianeto cúprico, que é tóxico ao ser humano e ao meio ambiente e que está presente em vários tipos de revestimentos nos quais uma camada de cobre é necessária. Esse estudo tem a finalidade de comparar revestimentos eletrodepositados a partir de soluções com cianetos e livres de cianetos, avaliando a qualidade do tratamento superficial de peças. Dessa forma, buscou-se produzir um revestimento com as mesmas qualidades de peças produzidas pelo processo tradicional. Nesse trabalho, foram utilizadas soluções tradicionais com 25 g.L-1 de cianeto e uma solução alternativa isenta de cianeto. As peças revestidas eram de zamak (liga de zinco com alumínio). Para avaliar a qualidade do revestimento obtido foram realizados ensaios acelerados de corrosão, dureza, comparação de espessura e morfologia da camada eletrodepositada. Os primeiros vestígios de corrosão foram verificados após 432 horas nos corpos de prova tradicionais e 1032 horas nos corpos-de-prova produzidos sem cianeto. Nos ensaios de dureza, obteve-se um pequeno ganho de dureza nas peças sem cianeto. A espessura da camada eletrodepositada, assim como a morfologia, foi similar para os dois tipos de processos. Os resultados obtidos demonstram a viabilidade técnica da utilização de soluções livres de cianeto na galvanoplastia.

The electroplating industries use in their productive process several types of chemical solutions, besides water, which after their life cycle must be discarded. Among them, there is cupric cyanide, which is highly toxic for humans and the environment, and it is present in many coatings where the copper layer is necessary. This study aims to compare coatings electrodeposited from solutions with cyanide and free cyanide, with those produced by the traditional process. This comparison involved parts and components of the same quality. In this study, traditional solutions with 25 g.L-1 of cyanide and an alternative solution with 0,015 mg.L-1 of cyanide were used. The parts were produced with Zamak (alloy of Zinc and Aluminum). In order to evaluate the quality of the coating, tests of accelerated corrosion, hardness, comparison of thickness and morphology of the electroplated layer were carried out. The first corrosion traces were detected after 432 hours in the traditional samples and 1032 hours in the free cyanide samples. In hardness tests, there was a better result for the free cyanide samples. The electroplated layer thickness and morphology was similar in both processes. The study results showed that there is technical feasibility in using free cyanide solutions in the electroplating sector.