Corrosion protection properties of conversion coatings formed onto 316 L SS from a solution containing molybdate and salicylate

CAMILA ABIGAIL RAMOS; MARÍA BELÉN GONZÁLEZ; SILVANA BEATRIZ SAIDMAN

Buenios Aires

Congreso; XI Corrosion Latinoamerican Congress - Latincorr 2018; 2018

Type 316L stainless steel (316L SS) is used in biomedical applications due to its good corrosion resistance as well as its mechanical properties. But this material has a tendency to suffer pitting corrosion in mediums containing aggressive ions such as Cl-. This localized attack releases metallic ions into the organism leading to a decrease in biocompatibility [1].The formation process of a conversion coating implies a chemical reaction between the substrate and the chosen conversion solution. As a result an inorganic, adherent and protective coating is obtained. Several studies have shown that both salicylate and molybdate are corrosion inhibitor anions of 316L SS [2, 3].In order to improve the corrosion resistance of 316L SS conversion coatings were synthetized from solutions containing molybdate and salicylate solutions. The obtained coatings were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The corrosion behavior of the modified electrodes was investigated in Ringer solution by open circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy. The results show that the presence of the conversion coatings improves the corrosion performance of the bare 316 L SS in presence of Cl- ions.