Materials Performance Supplements

CORTEC 2019

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

Issue link: https://mp.epubxp.com/i/1123822

Contents of this Issue

Navigation

Page 7 of 23

VAPOR PHASE CORROSION INHIBITORS organic components form a physical bond with the metal substrate. Formulations can include components with other functional- ities for added protective capabilities. The main difference of the VCI products vs. non-VCI products is the presence in the for- mulation of an ingredient with moderately high vapor pressure that can prevent cor- rosion in the vapor space without applying the VCI directly to the metal surface. 9-10 The typical examples of this class are organic amines and their salts with carboxylic acids (amino-carboxylates). The advantage of VCIs are that the volatilized molecules can penetrate hard to-reach spaces. When they reach the metal, the VCI attaches to it by the active group, creating a strong phy- sisorption mechanism. After the comple- tion of a hydrostatic test, the water must be discharged and be in compliance with environmental restrictions. It is required to comply with the Clean Water Act and the National Pollutant Discharge Elimination System (NPDES). 8 Experimental Procedure The main objective of this investigation was to study corrosion behavior of steel samples used as base material for pipe- lines to demonstrate effective corrosion protection of different VCIs. The choice of corrosion inhibitors for this study was made based on their functions and effec- tiveness in dif ferent aqueous solutions. VCI-A, VCI-B, and VCI-C are water-solu- ble products that have been demonstrated to inhibit corrosion of low carbon steel (CS) during hydrotests using fresh water. These inhibitors are a combination of film formers and VCIs. The main ingredients are salts of amines, organic acids of differ- ent chemical structures, and triazole. The main function of these products is to form a protective film with some VCI action. All these inhibitors are biodegradable and are surface modifiers. The steel used in this study was a low CS with a chemical composition (wt%) of 0.14 to 0.22% C, 0.3 to 0.65% Mn, ≤0.3% Si, ≤0.05% S, ≤0.045% P, and the remainder Fe. The CS samples were pretreated prior to the exper- iments by polishing with silicon carbide paper (240, 320, 400, 600, and fine polish- ing with 1.0 µm almina powder), degreased in acetone for 5 min in an ultrasonic bath, then rinsed with ethyl alcohol and dried in a FIGURE 3 Cyclic polarization behavior of UNS G10180 steel in 1.0% VCI-C at different aqueous solutions. FIGURE 4 Corrosion rate measurement (based on linear polarization resistance [LPR]) of UNS G10180 steel in 1.0% VCI-A at different aqueous solutions. FIGURE 5 Corrosion rate measurement (based on LPR) of UNS G10180 steel in 1.0% VCI-B at differ- ent aqueous solutions. 8 JUNE 2019 MATERIALS PERFORMANCE CORTEC SUPPLEMENT TO MP 8 JUNE 2017 MATERIALS PERFORMANCE

Articles in this issue

Archives of this issue

view archives of Materials Performance Supplements - CORTEC 2019