Triazole derivatives as chamber inhibitors of copper corrosion

Abstract

A set of physicochemical (ellipsometry, wetting angle measurement), electrochemical (electrochemical impedance spectroscopy, electrochemical polarization measurements) and corrosion methods (recurrent moisture condensation conditions, salt fog) was used to study the properties of adsorption films formed on copper by the chamber method from benzotriazole (BTA), 1,2,4-1H-triazole (TZ), tolyltriazole (TTA), 5-chloro-1,2,3-benzotriazole (Cl-BTA), 3amino-1H-1,2,4-triazole and 4-amino-1H-1,2,4-triazole vapors at 100°C. It was shown that upon one-hour treatment of copper with vapors of these compounds, nanosized hydrophobic adsorption films were formed on it, which hindered the thermal oxide growth but stabilized the passive state of the metal and improved its corrosion resistance. Of various triazole derivatives studied as chamber corrosion inhibitors, BTA and its derivatives can be distinguished. After one-hour chamber treatment of copper, the protective after-effect of their adsorption films grows symbatically with the saturated vapor pressure at the CT temperature, i.e., in the series BTA > TTA > Cl-BTA. This may indicate that at 100°C, there is not enough time for the formation of equilibrium adsorption films on the metal. There are reasons to believe that upon prolonged copper treatment with vapors of substituted benzotriazoles (24 hours or more), equilibrium adsorption films of inhibitors are formed thereon. In this case, the character of the effect of the properties of chamber inhibitors on their protective after-effect changes. Under these conditions, the best metal protection is provided by Cl-BTA, i.e., the least volatile and most hydrophobic of the substituted benzotriazoles studied.

Corrosion screening of chamber inhibitors for an aluminum alloy

“…Previously, we also observed similar extremal dependences of PAE on t CT on metals [9][10][11][12][13][14][15][16][17]. They appear due to the interaction of the two processes mentioned in the introduction, which differently affect the adsorption of ChIn vapors.…”

“…First of all, using the ellipsometry method, the integral thicknesses d of the surface layers formed on the alloy were measured. Unfortunately, separate measurement of the thicknesses d of oxide and adsorption films, like it was done in [12,13,[15][16][17], was impossible for AMg6 alloy due to the closeness of their refractive indexes.…”

“…Vapor-phase protection of metals is a reliable and cost-effective method for protection from atmospheric corrosion [1][2][3]. It is based on the use of corrosion inhibitors (volatile -VCI [3][4][5][6][7], or chamber inhibitors -ChIn [8][9][10][11][12][13][14][15][16][17]) that are adsorbed on a metal from the gas phase.…”

“…In view of this, low volatile inhibitors unsuitable for traditional vapor-phase protection can be used as ChIn. Examples of this are salts of higher carboxylic acids, octadecylamine and other substances [8][9][10][11][12][13][14][15][16][17] previously used only as contact inhibitors.…”

IFKhAN-140, a chamber corrosion inhibitor for brass

“…Development of the chamber treatment method was intensely performed for the past three years, and CINs suitable for the protection of monometallic products made of steel, copper, aluminum alloys, magnesium and zinc [4][5][6][7] have already been found. However, versatile CINs capable of simultaneously protecting several metals and alloys are not yet available.…”