Avaliação do efeito do benzotriazol como inibidor de corrosão para cobre em meio ácido
Antonio Vitor de Castro Bragaa, Aline Júlio Magdalenob, Lílian F. de Sennac, Aderval S. Lunad, Eliane D’Eliae, Dalva C. B. do Lagof
Abstract
Copper is a material widely used in heat exchange piping systems. Sometimes, these systems have their performance impaired due to the formation of corrosion products that are periodically formed. Acidic solutions are used to eliminate these corrosion products. However, besides removing the oxide formed, such solutions also cause a corrosive attack on the copper surface of the pipe. In order to reduce or prevent this attack, corrosion inhibitors can be employed. In this study, we evaluated the effect of benzotriazole (BTAH) as corrosion inhibitor for copper in sulfuric acid (H2SO4), varying the concentrations of H2SO4 and BTAH in order to verify the statistical influence of these variables on the impedance modulus. A three electrode cell was used, with copper (99.9% m/m) as the working electrode, platinum as the counter electrode and sulfate saturated as the reference electrode. The results show that higher impedance modules are obtained in the presence of BTAH, and consequently, a greater protective effect is given to the copper surface in a solution of H2SO4. The statistical analysis showed that the linear and quadratic components of the concentration of BTAH showed a significant and positive influence on the impedance modulus.
Keywords: Copper, Benzotriazole, Sulfuric Acid, Impedance.
Resumo
Cobre é um material largamente usado em tubulações de sistemas de troca de calor. Estes sistemas têm, por vezes, seu desempenho prejudicado devido à formação de produtos de corrosão que são periodicamente formados. Soluções ácidas são usadas para a eliminação desses produtos de corrosão. Porém, tais soluções, além de removerem o óxido formado, também causam um ataque corrosivo à superfície de cobre da tubulação. Com o objetivo de