S. V. Oleinik

Corrosion Inhibition of Steel in Lithium Bromide Brines

The inhibiting effect of phosphomolybdenic acid (PMA) on the corrosion of steel (St3) in 65% lithium bromide solution has been studied in a temperature range from 80 to 230°C and at pH 5.0–8.5. Corrosion and electrochemical studies showed that the efficiency of PMA as a corrosion inhibitor increases with an increase in temperature and pH of the LiBr brine. The ambiguous behavior of PMA in solutions at low temperatures and pH was analyzed. A blend of PMA with a low-temperature inhibitor (IFK) was suggested. It was shown that these inhibitors manifest synergism and the composition has high inhibiting properties at elevated temperatures. The effect of PMA on the effective activation energy of the corrosion process was analyzed.

Modification of plasma electrolytic coatings on aluminum alloys with corrosion inhibitors

Protective properties of the coatings produced by plasma-electrolytic oxidation on different aluminum alloys in a phosphate-borate electrolyte are studied. Filling the coatings with corrosion inhibitors of IFKhAN family is shown to substantially improve their corrosion resistance in chloride environments. Modification of the coatings with corrosion inhibitors provides an increase in the contribution of hydrophobization to the improvement of the protective characteristics of coatings.

Corrosion inhibitors in PEO-coatings on aluminum alloys

The corrosion properties of coatings obtained by plasma-electrolytic oxidation (PEO) in silicate and borate electrolytes on AMg-5 and D17 aluminum alloys are studied. An increase in PEO-coating thickness on AMg-5 alloy obtained in borate electrolyte does not provide an increase in their corrosion resistance in chloride media. The greatest contribution to increasing the corrosion resistance of such coatings is made by filling them with corrosion inhibitors. Additional hydrophobization by low molecular fluoroplast increases the protective action of such inhibited coatings.

Protection of Low-Carbon Steel from Carbon Dioxide Corrosion with Volatile Inhibitors. I. Liquid Phase

It was shown that many of the known basic inhibitors of atmospheric and hydrogen sulfide corrosion (D-4-3, N,N-diethylamino-2-methylbutan-3-one, and N,N-diethylaminoethanol) fail in CO2-containing electrolytes. Carbon dioxide corrosion in solution can be suppressed only in the presence of more hydrophobic octylamine and its higher homolog, namely, amine A. The new highly passivating inhibitors IFKhAN-72 and IFKhAN-74 are even more effective. IFKhAN-72 is superior to amine A (the best amine-based inhibitor among those studied) in protection effect and suppresses CO2 corrosion of steel over a wide temperature range by substantially retarding both electrode reactions. Because of its high penetrating ability, IFKhAN-72 can protect steel already covered with corrosion products. In addition, this inhibitor has a prolonged aftereffect.

Volatile inhibitor of carbon dioxide corrosion of steel

Corrosion and electrochemical methods were used to compare the protective properties of cyclohexalamine and a new inhibitor, IFKhAN-70, under conditions simulating carbon dioxide corosion of industrial pipeline steel. The inhibiting properties of the latter inhibitor were found to be markedly higher. IFKhAN-70 can passivate steel; it is effective in the presence of corrosion products on the surface and displays an anti-corrosion aftereffect.

IFHANAL-3 Inhibited Chromate-Free Conversion Coatings on V95T2 Aluminum Alloy

Alloys in the Al–Cu–Mg–Zn system are known to be characterized with high corrosion resistance in both atmospheric and aqueous media. It was earlier demonstrated that the alkaline chromate-free converting composite IFHANAL-3 enabled one to produce coatings with protective properties not inferior to those of conventional chromate coatings on a number of aluminum alloys, including that of grade V95 with different thermal treatment. The present work was devoted to studies of the effect of different complexing agents on the oxidation process and protective properties of coatings on V95T2 alloy. The studied modifying dopants decrease the concentrations of different oxides in the composition of conversion coatings, thus facilitating the adsorption of corrosion inhibitors and improvement of their protective properties. The decrease of the oxidation temperature in the solution of IFHANAL-3 modified with inhibitors of the azol type does not ly affect protective properties of the formed coatings.

Submicron free-chromate chemical conversion coatings on AMg-3 aluminum alloy

Coatings obtained in solutions of permanganates are known alternatives to thin chromate conversion coatings on aluminum alloys. However, permanganate ion is an insufficiently effective corrosion inhibitor for aluminum in the acidic medium, and, therefore, modified additives are introduced into converting solutions based on it. The present research is devoted to studying the corrosive characteristics of coatings produced by chemical oxidation in the IFKhANAL-2 permanganate composition and its modifications on AMg-3 aluminum alloy. It is shown that iron and nickel salts are most effective as modified additives and subsequent filling of produced coatings in corrosion inhibitor solutions increases their protective properties up to the level of standard chromate coatings. The researched coatings provide protection for 1.5 years under conditions of a humid tropical climate.

Features of development of corrosion and inhibition of steel upon abrasive-dilatant cleaning

Increasing the quality of hydrojet cleaning can be provided by employment of additives, which provide dilatant properties to the water-abrasive pulp, i.e., increase viscosity with an increase in flow velocity. However, the use of any methods of hydrocleaning creates conditions for intense corrosion of a cleaned moist surface. The rate of development of corrosion centers of carbon steel after hydroabrasive and abrasive-dilatant cleaning and the influence of a series of corrosion inhibitors are analyzed. It is shown that optimal inhibitors are quite efficient and can decelerate the rate of formation and growth of corrosion centers by a factor of 10.

Chromate-free conversion coatings on 1370 aluminum alloy

Formation and protective properties of conversion coatings on 1370 aluminum alloy that were obtained in an IFKhANAL-3 alkaline conversion solution are studied. The subsequent filling of the coatings in an inhibitor solution is shown to produce coatings that are resistant to pitting corrosion in chloride environments. Results of corrosion experiments reveal good protective properties of the coatings that are no worse than conventional chromate coatings.

Chemical oxidation of lithium-containing aluminum alloy 1424

The possibility of obtaining protective conversion coatings on the surface of lithium-containing aluminum alloy 1424 in chromate-free conversion solutions IFKhANAL-1 and IFKhANAL-3 is shown. The kinetics of formation, composition, and protective properties of these coatings are studied. It is shown that the introduction of modifying additives and corrosion inhibitors into the IFKhANAL-1 oxidizing solution significantly increases the resistance of formed coatings to pitting corrosion in chloride-containing environments.