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Ni-Nb binary metallic glass was synthesized by the melt spinning technique with a tangential wheel rotation speed during cooling of 6 m/s obtaining a glassy matrix which was characterized by X-ray diffraction (XRD). Electrochemical properties were determined by electrochemical impedance spectroscopy (EIS). The results show that this metallic glass is very resistant to corrosion, being better when exposed to corrosive media with pH = 0 and 7 in chloride ions presence. However, at pH = 14 the passive film is not homogeneous, and the corrosion rate increases with respect to the other systems.

The 3a-hydroxymasticadienoic compound (3-HM) was evaluated as a corrosion inhibitor in presence of chlorides using Electrochemical Impedance Spectroscopy (EIS). The results obtained showed the best concentration is 50 ppm with an inhibition efficiency of 68.4% for sterling silver. This organic molecule exhibits anodic-like behavior as an inhibitor. 3-HM acid inhibition is maintained up to 480 hours with 88.86% efficiency. Finally, the type of adsorption is of the combined type according to the Langmuir model.

The polyketide 5-methylmellein was isolated from Biscogniauxia sp. (Xylariaceae), an endophytic fungal strain obtained from an epiphytic bromeliad species collected in the Ecological Reserve at the Universidad Nacional Autónoma de México. This compound was investigated as a corrosion inhibitor for metallic materials, such as API 5L X65, in a corrosive 3% NaCl solution using electrochemical technique (electrochemical impedance spectroscopy). The results showed that 50 ppm of 5-methylmellein protected the metallic surface. Measurements at different rotation rates (500 and 1000 rpm) indicate that this compound decreases the charge transfer resistance (Rct) as a result of the desorption of organic molecules.

By means of the technique of Electrochemical Impedance Spectroscopy, the protective effect of Paraloid as coating and with the addition of strictosamide as corrosion inhibitor was analyzed. At a concentration of 50 mg/m2, a 69% of efficiency was reached, being the best concentration to protect the metallic surface. However, when the strictosamide was applied in concentrations of 20 mg/m², it was observed that the corrosion was promoted, even more than when the Paraloid was not applied.