Susceptibility to Localized Corrosion of ASTM F745 and UNS S32750 Stainless Steels. Influence of pH and Cytotoxicity Evaluation

GREGORUTTI, RICARDO W.; GRAU, JORGE E.; CASTROGIOVANNI, DANIEL; PARISI, JULIETA; REIGOSA, MIGUEL; ELSNER, CECILIA I.

Innovations in Corrosion and Materials Science (Formerly Recent Patents on Corrosion Science)

Benthan Science

Lugar: Sharjah; Año: 2020 vol. 10 p. 47 - 57

2352-0949

Abstract: Cyclic polarization tests assessed in 0.9 wt% NaCl solution in the pH range 4 to 9 showed that austenitic ASTM F745 is more susceptible to suffer localized corrosion than UNS S32750. Although its passivity range increased with pH (from 0.460 V to 0.600 V), its repassivation capacity diminished. In contrast, UNS S32750 showed an extensive passive region, reaching potentials close to 1.0 V/SCE. However, it has shown a tendency to develop transpassive reactions at low pH. Galvanostatic tests did not reveal the onset of localized corrosion, which would indicate that the increase in current density at potentials close to 1.0 V/SCE could be attributed to the reaction of oxygen, as well as to transpassive reactions.The cytotoxicity was analysed by Neutral red, MTT and collagen assays, using UMR- 106 osteoblastic cells. The results indicated that no adverse effects were observed on cells exposed to the extracts of both stainless steels. Neutral red and MTT assays showed high cell viability, however, it was observed a slight reduction in the collagen production. Both stainless steels showed high cell viability, however, it was observed a slight reduction in the collagen production. The cytocompatibility was also satisfactory, since the cells seeded on the surfaces had adequate proliferation, without evidence of changes in their morphology.