The role of organics in metallic passivation

Abstract

SummaryOrganic substances are known to affect, electrochemical reactions. The passivation characteristics of iron have been shown tc? be drastically altered in the presence of certain ions. Since passivation mnst occur to preserve the physical integrity of some materials in viuo, a study was init,iated to determine the effect of alanine, bovine plasma albumin, and cyst,ine on t,his phenomenon for nickel and copper.The procedure was as follows: ( 1 ) potential pH diagrams which show stable metal-containing forms with respect to pH and electrical potential were constructed to interpret anodic dissolution data; (b) measurements were made to det,ermine potential ranges in which organic adsorpt.ion occurs; and (3) data on electrical potential of the metal and associated current were taken for const~ruction of anodic dissolution curves.The results showed that the presence of cystine inhibited the passivation of nickel and improved the passivation tendency of copper. The other organic substances had little or no effect, on passivation. A possible mechanism for these effects is proposed. Further, t,he results showed a relationship between the onset of passivation and the potentials where metal-containing solid substances become t.hermodynamically stable, &s determined from the potential pH diagrams.The marked retardation of metallic dissolution due to surface alteration, termed passivation, has significant engineering importance. Under common environmental conditions many materials, such as stainless steel and titanium, depend on the occurrence of this phenomena for their physical integrity. Thus, a knowledge concerning

Electrochemical impedance spectroscopy study of the adsorption behaviour of α-lactalbumin and β-casein at stainless steel

“…In our previous papers [15,16], we showed that the adsorption of BSA and b-LG onto an austenitic stainless steel surface enhances the dissolution of the passive oxide film on the surface, thus increasing corrosion of the alloy. Svare et al [23] showed that horse serum affects the dissolution of Ni, which is one of the major components of austenitic stainless steels. Williams et al [24] found that 316L stainless steel exhibited greater corrosion in the presence of serum proteins while Woodman et al [25] have found that the predominant corrosion products from 316L stainless steel were organometallic complexes with serum proteins.…”

“…Industrial corrosion also represents a large problem, and therefore studies [15,16,[23][24][25][26] have been made to evaluate the effect of proteins on the corrosion of metallic materials such as stainless steel typically used in the food and pharmaceutical industries and in medicine. It was generally established that proteins interact and alter the corrosion behaviour of metallic materials in two ways: adsorption and chelation.…”

Interfacial Behavior of β-Lactoglobulin at a Stainless Steel Surface: An Electrochemical Impedance Spectroscopy Study

“…In our previous paper (14), we showed that the adsorption of bovine serum albumin (BSA) onto an austenitic stainless steel surface enhances the dissolution of the passive oxide film on the surface, thus increasing corrosion of the alloy. Svare et al (18) showed that horse serum effected the dissolution of Ni, which is one of the major components of austenitic stainless steels. Williams et al (22) found that 316L stainless steel exhibited greater corrosion in the presence of serum proteins.…”

“…Therefore, the overall costs of cleaning are very high. A large number of investigations to better understand the process of fouling have been reported (17)(18)(19), but a real breakthrough in the complete control of fouling has not been reached. This is mainly due to the complexity of the dairy systems and a lack of understanding of the mechanism of fouling.…”

Susceptibility to corrosion of laser welding composite arch wire in artificial saliva of salivary amylase and pancreatic amylase

“…[12][13][14][15][16] Svare showed that specific amino acids could influence alloy passivation: for cysteine in Ringer's the passivation of Cu was improved, but alanine and albumin had little or no effect. [17] Therefore, interaction of metallic materials and protein composition, especially the enzymes in saliva, and their consecutive influences on corrosion need more research.…”