Digital Holography Study of the Inhibitory Effects of Polyaspartic Acid on the Anodic Dissolution of Inconel® 600

Abstract

Electrochemical methods were used in conjunction with digital holography to study the effects of an environmentally friendly inhibitor, polyaspartic acid (PASP), on the anodic dissolution of Inconel® 600 in a 0.04 M HCl solution. The pitting inhibition ability was enhanced and the inhibition efficiency increased with the PASP concentration, reaching 84.13 % at 6.66 g L−1 PASP. A digital holograph was used to observe the in situ hydrolysis of M2+ (M = Ni and Fe) near the electrode surface during anodic dissolution and showed the formation of a surface film on the electrode. The inhibitory effects of PASP on Inconel® 600 may be caused by the adsorption of PASP and the formation of a PASP metal complex (PASP-M complex), which may seal defects in the surface film.

Keywords

• inconel® 600
• polyaspartic acid
• inhibitor
• digital holography