Developing an Algorithm for the Calculation of a Painting Chamber

Theoretical Foundations of Chemical Engineering - This team of authors presents the development of an algorithm and its practical application in the software for solving the problems of...     

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.     

Steel Protection from Carbon Dioxide Corrosion with Volatile Inhibitors. II. Vapor Phase

It was shown that the high neutralizing properties and volatilities of some of the inhibitors studied are insufficient to protect steel under these conditions. The inhibitive effect of modified, more hydrophobic aliphatic amines in carbon dioxide under conditions of periodical wetting proved to be enhanced. New inhibitors, namely, amine A and IFKhAN-72, are effective against carbon dioxide corrosion and retain their aftereffects for a long period of time.     

Effects of atomic relaxation and the electronic structure of niobium (100) and (110) surfaces

A comparative analysis of the atomic relaxation and electronic structure of niobium (100) and (110) surfaces has been carried out using the VASP-PAW method. The relaxation-induced changes in interlayer spacings of surface layers demonstrate an oscillating behavior but they substantially differ for the two analyzed surfaces; namely for the (110) surface with the closest atomic packing two outermost surface layers are contracted by 4.3% and the relaxation becomes noticeable for three outer layers, while for the more “open” (100) surface these quantities equal 13.1 and six layers, respectively. An analysis of the layer-by-layer distribution of the densities of states, spatial distribution of the charge density, and densities of states at the Fermi level indicates that the most considerable changes near Fermi level take place for (100) surface.     

On the Coadsorption of Mephenaminate and Phenylundecanoate Anions at Passive Iron

Adsorption of sodium mephenaminate (SMEP), sodium phenylundecanoate (SPU), and their mixtures by oxidized iron from a borate buffer (pH 7.4) at the constant potential E = 0.2 V was studied by ellipsometry. Like the adsorption of the previously studied SMEP, that of SPU obeys the Frumkin equation with the higher Gibbs energy of adsorption (− ΔG _A ⁰ = 33.1 kJ/mol). The Frumkin equation fails for the adsorption of an equimolar SPU + SMEP mixture (inhibitor IFKhAN-31), which is described by the Bockris equation. The calculations showed that −Δ G _A ⁰ = 41.7 ± 0.2 kJ/mol and the number of water molecules displaced by an adsorbed inhibitor species from the metal-solution interface is n = 4. It was found that SMEP anions preadsorbed at oxidized iron do not affect the shape of the SPU adsorption isotherm, yet altering its constants. In the case of preadsorbed SPU, the SMEP adsorption isotherm changes its shape and cannot be described by any known adsorption equation. In addition, SMEP begins to adsorb at the electrode in lower concentrations; i.e., PU anions stimulate the adsorption of SMEP. __________ Translated from Zashchita Metallov, Vol. 41, No. 6, 2005, pp. 573–578. Original Russian Text Copyright ? 2005 by Kuznetsov, Andreeva.     

Electrodeposition of Copper-Containing Polymer Coatings from Sulfate Electrolytes Containing N-Methylpyrrolidone

In sulfate electrolytes for copper plating, N-methylpyrrolidone (MP) was found to form stable 2 : 1 complexes with the metal. The nature of electroactive species at the copper cathode depends on the MP concentration. In a concentration range from 10⁻⁴ to 10⁻² mol/l, the electrode reaction involves complexes of discharging metal ions with adsorbed MP molecules, the complexes being formed in the surface layer. At higher MP concentrations, a slow chemical step associated with dissociation of complex species in the bulk of the solution precedes ion discharge. The inhibitive effect of MP on copper electrodeposition is due to adsorbed MP molecules at the electrode; the adsorption value determines the efficiency of the additive and the wear resistance of the coating. __________ Translated from Zashchita Metallov, Vol. 41, No. 5, 2005, pp. 463–466. Original Russian Text Copyright ? 2005 by Kuznetsov, Skibina, Kuznetsova, Loskutnikova, Sokolenko.     

Role of Adsorbed Metal Complexes in Cadmium Electrodeposition from Iodide-Containing Aqueous Ethanol

Structurization phenomena in a mixed solvent were found to determine, by affecting the solvation degree of an anion, its adsorptivity at the electrode and, consequently, the surface concentration of the nonaqueous solvent. The formation of activated Cd²⁺ complexes with iodide anions in an adsorbed layer is usually accompanied by accelerating the electrode reaction. The desalting effect of the mixed solvent in the zones of its structural stabilization is mainly manifested as the enhanced adsorptivity of iodide anions and the correspondingly facilitated discharge of metal ions. The highest discharge rate was found at ₂ 0.9 when the structure of EtOH is ordered with monomeric water molecules. The highest surface concentration of EtOH and the lowest rate of cadmium electroreduction correspond to a structurally disordered mixture ( ₂ 0.4).     

Alloying of Fe−Co−Ni−Al−Cu system alloys with hafnium and zirconium

Conclusions Alloying of Fe–Co–Ni–Al–Cu-base magnetically hard alloys with hafnium broadens the area of existence of the bcc solid solution. The oxidation resistance of the alloys increases and the temperature of the start of intense oxidation increases from 400 to 900°C.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 51–53, April, 1987.     

Test complex for the onboard navigation system of an airport ground vehicle

An experimental model of the onboard integrated navigation system for airport ground vehicles designed for use as part of an advanced surface movement guidance and control system is considered. The technique and the results of field tests of the system are presented. The composition and design of the mobile test stand are described.