Abstract:Corrosion is generally present in metal materials, especially when they are involved in several industrial activities. Their deterioration is induced by the physicochemical interaction between the metal and the corrosive environment, which causes great problems in several activities. The petrol sector is one of the most damaged as the constituents of perforation fluids and petroleum production water influence corrosion. Conventional anti-corrosion techniques are employed to prevent the loss of highly used industrial material; they include coatings, change of environment, cathodic and anodic protection and inhibitor treatments using organic compounds. Broadly speaking, this article describes the main anti-corrosion protection methods, corrosion in petroleum industry, and the anti-corrosion agents used in the industrial sector.Keywords: Corrosion; corrosion inhibitors; anti-corrosion protection; corrosion in petroleum industry. ResumoA corrosão está presente nos materiais metálicos em geral e, em especial, envolvidos nas diversas atividades industriais. A deterioração destes é causada pela interação físico-química entre o material e o meio corrosivo, onde causa grandes problemas nas mais variadas atividades. Um dos setores que mais se prejudica com a corrosão é o petrolífero devido a influencia de constituintes dos fluidos de perfuração e da água de produção. Para evitar as perdas dos materiais de elevado uso industrial, são utilizadas técnicas anticorrosivas que incluem os revestimentos, as técnicas de modificação do meio, a proteção catódica e anódica e, os inibidores de corrosão como a utilização de compostos orgânicos. Este artigo descreve, em linhas gerais, as principais técnicas de proteção anticorrosiva, a corrosão na indústria do petróleo e os agentes anticorrosivos utilizadas no meio industrial.Palavras-chave: Corrosão; inibidores de corrosão; proteção anticorrosiva; corrosão na indústria de petróleo.

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The inhibition ability of four 1,3,4-thiadiazolium-2-phenylamine chlorides (MI 1-4) towards carbon steel corrosion in 1.0 M HCl and 0.5 M H 2 SO 4 was evaluated by potentiodynamic polarization (PP), the linear resistance to polarization (LRP) and electrochemical impedance spectroscopy (EIS) at different inhibitor concentrations. Polarization curves showed that all the evaluated compounds act as mixed inhibitors with a tendency to become anodic in both acids. EIS plots indicated that the presence of all compounds increases the charge transfer resistance of the corrosion process, thus increasing the corrosion inhibition efficiency in both acids. These derivatives exhibit good inhibition properties in both acidic solutions, and the adsorption on the carbon steel surface follows the Langmuir isotherm model in both acidic media. Theoretical calculations were also performed, and the calculated quantum parameters correlated with the experimental results, thus supporting the conclusions reached from the electrochemical data.