Influence of a Rhamnolipid Biocomplex on the Corrosion of Duralumin in the Case of Mechanical Activation of its Surface
- PDF / 1,144,339 Bytes
- 9 Pages / 594 x 792 pts Page_size
- 107 Downloads / 166 Views
INFLUENCE OF A RHAMNOLIPID BIOCOMPLEX ON THE CORROSION OF DURALUMIN IN THE CASE OF MECHANICAL ACTIVATION OF ITS SURFACE I. M. Zin’,1, 2 O. V. Karpenko,3 S. A. Kornii,1 H. H. Midyana,3 M. B. Tymus’,1 O. P. Khlopyk,1 I. V. Karpenko,3 and V. M. Lysyak3 The problem of inhibition of the corrosion of D16T aluminum alloy by surface-active products obtained as a result of the biosynthesis of Pseudomonas sp. PS-17 strain (rhamnolipid biocomplex) is studied by using the electrochemical and quantum-chemical methods. It is shown that the rhamnolipid biocomplex is capable of the efficient inhibition of the corrosion of D16T aluminum alloy in a synthetic acid rain. The efficiency of inhibition increases with the concentration of biosurfactant. As the critical concentration of micelle formation is attained, a subsequent increase in the amount of biosurfactant in corrosive media does not lead to any noticeable intensification of its protective (anticorrosion) effect. The mechanism of corrosion inhibition is connected with the adsorption of biosurfactant molecules on the surface of aluminum alloy with the creation of barrier films and the formation of difficultly soluble complex compounds on the anodic sections of the metal as a result of the interaction of rhamnolipid with aluminum ions. The rhamnolipid biocomplex efficiently prevents the corrosion of aluminum alloy in the case of its mechanical activation. The biosurfactants added to the corrosive medium increase the rate of recovery of protective films on the aluminum alloy in the stage of repassivation by a factor of 2–4, as compared with the uninhibited medium. Keywords: rhamnolipid biocomplex, corrosion inhibition, aluminum alloy, repassivation, polarization, corrosion current, quantum-chemical calculations.
Organic inhibitors of corrosion are represented by various classes of compounds. Most of these compounds are synthetic and cannot be found in the nature [1]. These environmentally dangerous compounds are difficultly decomposed and negatively affect the biosphere. Therefore, it is necessary to create new corrosion inhibitors characterized by the higher efficiency and environmental safety as compared with the available substances. In recent years, much attention of the researchers is given to the so-called “green” inhibitors obtained from plant raw materials or the wastes of their processing [2, 3]. Thus, in particular, some inhibitors of the corrosion of steels were produced from the extract of rape grist. These low-cost materials do not contain any toxic substances and are characterized by a sufficiently high degree of protection [4]. In [5], the extracts of oak bark and chips were used as a basis for the creation of synergistic environmentally safe inhibiting compositions. They protect carbon steels against corrosion in water by 80–95%. The role of active anticorrosion components of plant extracts is played by nontoxic flavonoids, alkaloids, and other natural products [3]. As a rule, the presence of tannins, cellulose, and polycyclic compounds in the extracts improves the
Data Loading...
