Authors: R.V. Kashkovsky

Title of the article: Evaluation of partial protective contributions of surface films under inhibition of corrosion of metals: ways of development

Year: 2017, Issue: 6, Pages: 210-218

Branch of knowledge: Chemical technology

Index UDK: 620.197.3

DOI: 10.26730/1999-4125-2017-6-211-219

Abstract: key issue in the methodology for estimating the partial contributions of a superficial protective film "corrosion products - inhibitor" is the determination and consideration of their mutual influence. It is known that film of corrosion products (CP) in the inhibited medium grows under the influence of the adsorbed inhibitor. The appearance, growth and structural changes of CP film in time also affect the features of inhibitor adsorption. Now this kind of interference is extremely difficult to account due to the lack of studies in this area. For this reason, such estimate can be carried out only with the assumption of additivity of growing inhibitor and CP films, i.e. absence of their mutual influence on partial protective efficiencies. The initial theoretical basics of the method for estimating these contributions are considered in the present work. New approaches to its refinement and detailed specification are developed here as well. In particular, the possibilities were identified for taking into account the changes in the protective effect of a CP film in the inhibited medium by correlating the total mass losses of metal with the background medium. The importance of taking into account the dissolution and peeling of the CP film for the final evaluation is discussed also. Noticeable difference in the results of analysis is obtained using the approaches based on different interpreta-tions of additivity, namely the additivity of protective effects and that of inhibition coefficients. Results of the several estimation methods including taking into account the change of the film thickness of CP in the inhibited medium compared to the background, as well as various methods of algebraic representation of additivity are compared on the example of inhibiting hydrogen sulfide corrosion (HSC) in steel in the liquid phase.

Key words: corrosion of metals contribution corrosion products inhibitor steel hydrogen sulfide amines

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