Volatile inhibitors of atmospheric corrosion. III. Principles and methods of efficiency estimation

It has been shown that it is possible to create a technology for efficient protection of steel items by short-term treatment in vapors of low-volatile corrosion inhibitors in specialized chambers at elevated temperatures. It is suggested to call this technology based on the protection after-effect of adsorbed inhibitor films as "chamber treatment" and the compounds used therein as "chamber inhibitors". A number of methods (accelerated and field corrosion tests, potentiodynamic polarization measurements, ellipsometry, surface wetting angle measurement) were used to study the formation of adsorption films of 1,2,3benzotriazole (BTA), octadecylamine (ODA), and a mixture thereof on steel from a gas phase. It has been found that the temperature plots of the protection after-effect of the inhibitors studied have a maximum at 120°C. The adsorption films that stabilize the passive state of steel (both in the absence of chloride and in chloride-containing electrolytes) and noticeably hydrophobize the surface are already formed within one hour of chamber treatment. The adsorption films of ODA and its mixtures with BTA hinder steel corrosion initiation under conditions of recurrent moisture condensation more than 100-fold and have significantly better protective properties than the adsorption films of BTA. It has been found that adsorption of inhibitors hinders the thermal oxidation of steel. The total thickness of the surface layers on steel (oxide film and adsorbed inhibitor) responsible for the protection after-effect depends on the inhibitor nature but does not exceed 15 nm. It has been shown that treatment in vapors of ODA or its mixture with BTA markedly increases the corrosion resistance of low-carbon steel under weathering conditions and can be used for the interoperational protection of metal items.

Section: Introductionmentioning

confidence: 99%

Octadecylamine, 1,2,3-benzotriazole and a mixture thereof as chamber inhibitors of steel corrosion

2018

“…Among them, the use of vapor phase inhibitors (VCI) is an effective and convenient means [1][2][3][4][5][6][7][8]. However for the reason of their expensiveness and increasing awareness of health and ecological risks, attention is being drawn towards finding highly efficient, cheap and non-toxic inhibitors.…”

Section: Introductionmentioning

confidence: 99%

A comprehensive study of grape pomace extract and its active components as effective vapour phase corrosion inhibitor of mild steel

2018

The inhibition efficiency of grape pomace extract (GPE) and its main constituents (2-phenylacetaldehyde, hexanal) as a green volatile corrosion inhibitor for the temporary protection of mild steel was investigated. Weight loss measurements and potentiodynamic polarization techniques were all used for this assessment. The major constituents of GPE were identified by GC-MS analysis. Grape pomace extract inhibited mild steel corrosion under conditions of periodic condensation of moisture with a protection efficiency of ~92%. The gravimetric measurement indicates that inhibition efficiency shows direct proportional relation with concentration of inhibitor. The corrosion rate reduction is time dependent, and the highest protection values were achieved only in 48 h. Inhibition efficiency increases in the order: grape pomace extract > 2-phenylacetaldehyde > hexanal. The grape pomace extract and main components acted as a mixed-type inhibitor with predominant cathodic effectiveness. Structural characterization by using SEM, AFM images and FT-IR analysis further supported the electrochemical and weight loss measurements results obtained.

“…Nevertheless, protective films on zinc surface can be obtained not only from solutions but also from the gas phase. To do this, volatile inhibitors are used [11][12][13][14][15][16][17][18], which adsorb on the surface of metals, forming adsorption layers capable of inhibiting corrosion. Typically, compounds or mixtures of compounds, that have a high equilibrium saturated vapor pressure (р s ) under normal conditions are used as VCIs.…”

Section: Introductionmentioning

confidence: 99%

A new corrosion inhibitor for zinc chamber treatment

2018

Thin organic films on metal surfaces can be obtained by adsorption of volatile (vaporphase) inhibitors (VCI), which, despite the extremely small thickness, provide high corrosion resistance under various atmospheric conditions. However, there is a problem in the practical application of compounds with high vapor pressure, namely, the air-tightness of the joint packaging of VCI and metal products. Infringement of packing air-tightness entails desorption of VCI from the metal surface followed by its corrosion. A fundamentally new opportunity for creating thin films capable of preventing corrosion of metal products in a humid atmosphere during their transportation and inter-operation storage is opened by the treatment of an item or semi-finished product to be protected in hot vapors of non-toxic compounds with low volatility under normal conditions. They evaporate at elevated temperature (t) in the enclosed space of a chamber and strongly adsorbed on the metal to create stable thin films that provide a long-term protective aftereffect under atmospheric conditions. This method of vapor-phase protection by chamber corrosion inhibitors has broad prospects of practical application.It has been proven by a complex of accelerated corrosion, electrochemical and optical methods that chamber treatment of zinc with vapors of low volatile corrosion inhibitors at t ≤ 100°C is capable of forming films on zinc surface that possess a prolonged protective after-effect. It has been shown that short-term chamber treatment in the vapor of a new inhibitor, IFKhAN-121, provides effective temporary protection of zinc, both in accelerated tests and when exposed in the industrial atmosphere of Moscow for 1 year.