The Inhibition of Hydrogen Embrittlement in SAE 4340 Steel in an Aqueous Environment with the Rare Earth Compound Lanthanum 4 Hydroxy Cinnamate

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2012-07, Vol.43 (7), p.2251-2259
• Main Authors: Hinton, B. R. W., Behrouzvaziri, M., Forsyth, M., Gupta, R. K., Seter, M., Bushell, P. G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Exact sciences and technology; Fractures; Hydrogen; Materials Science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metallic Materials; Metallurgy; Metals. Metallurgy; Nanotechnology; Steel; Strain rate; Structural Materials; Surfaces and Interfaces; Thin Films; Trace elements
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-012-1103-y

A preliminary study showed that the inhibitor lanthanum 4-hydroxy cinnamate ((La4OHcin) 3 ) at a concentration of 400 ppm prevented the hydrogen embrittlement (HE) of SAE 4340 steel tensile specimens when tested under slow strain rate conditions in a 0.01M NaCl. In the presence of the inhibitor, a complex film formed on the surface of specimens during the slow strain rate test (SSRT), and no corrosion pits were detected. Electrochemical polarization studies indicated that the La(4OHcin) 3 acted as an anodic inhibitor in the NaCl solution. This article also discusses the mechanism of HE inhibition by La(4OHcin) 3 .