Vol 54, No 7 (2018)

The data on computer simulation of the phase composition of Fe–Cr–Ni–Ti using the example of ZI 130 steel were presented. The purpose of simulation was the precise determination of percentage of titanium, at which alloys has a maximum corrosion resistance. Simulation data can be a basis for correction of chemical composition of corrosion resistant alloys stabilized by titanium.

The results of an investigation of the chemical composition, structure, topography, and mechanical properties of surface layers of armco-iron after implantation of nitrogen ions under various conditions are given. Using X-ray electron spectroscopy, the implanted nitrogen distribution profiles are determined and the formation of nonstoichiometric iron nitrides and oxynitrides is shown. Using X-ray analysis and electron energy-loss spectroscopy of dimensional fine structures, the atomic and local atomic structure of the ion-modified layers is studied.

The simultaneous application of optical and electrochemical methods has allowed us to investigate in detail the initial stages of the local dissolution of steel in a chloride-containing solution. The incubation period, the rate of defect formation on the surface, and the rate of individual defects development have been evaluated with high precision. It has been demonstrated that the emergence and development of local defects is possible under potentials more negative than the pitting potential determined from the polarization curve. The metal dissolution rates that occur at the initial stages of pitting formation from an individual defect have been calculated. It has been established that the initial process of defect formation under anode polarization consisted of two stages. The first stage corresponds to the emergence and intense formation of the freshly formed defect and is primarily determined by electrode potential. The second stage is shown by the development of a defect that did not depend on potential.

A comparative estimation of long-term prediction of corrosion losses of carbon steel and zinc has been performed. Predictions have been obtained by means of the exponential-linear function and the dose-response function for the continental part of Russia.

The adsorption, protective, and passivating effect of some sodium salts of higher carboxylates and sodium dioctyl phosphate on zinc in borate buffer solution with pH of 7.4 were studied. It has been shown that sodium oleyl sarcosinate has the best protective and adsorption properties. It has been established that the adsorption of oleyl sarcosinate on zinc is multilayer, which contributes to its best protection under anodic dissolution and in a humid atmosphere with periodic condensation of moisture on the samples. Treatment of Zn in aqueous solutions of inhibitors increases the time until the appearance of the first corrosion lesions on it under conditions of humid atmosphere 2.5–4.5 times.

This article studies corrosion of 08PS steel in 2 M H₂SO₄, 2 M H₃PO₄ and their mixtures (t = 20–80°C). Addition of a mixture comprised of 4.5 mM IFKhAN-92, a triazole derivant, and 0.5 mM KNCS inhibits corrosion of low carbon steel in these media. The existence of Fe(III) in the solutions worsens steel protection by this composition of inhibitors. The most stable against the impact of Fe(III) cations are the solutions of H₃PO₄ or its mixture with sulfurous acid with high content of H₃PO₄. Addition of hexamethylenetetramine (0.20 M) to these media enables protection of low carbon steels in acid mixed solutions with high content of H₂SO₄ (up to 60%) containing Fe(III). Upon etching of steels or acid washing of steel equipment in the case of potential accumulation of Fe(III) salts in such media accelerating metal corrosion, H₂SO₄ + H₃PO₄ solutions are recommended containing up to 60% H₂SO₄ and IFKhAN-92 + KNCS + hexamethylenetetramine composition, since in such a solution steel corrosion is minimized due to its interaction with Fe(III) compounds.

The present paper is devoted to the study of a limiting stage of silicon carbide diffusion growth at the pyrocarbon–silicon melt interface. The main diffusion parameters of the process have been determined using a generalized kinetic equation and experimental data. The main kinetic law has been written for this stage.

The presence of copper-containing intermetallide phases significantly decreases the corrosion resistance of 1441 aluminum alloy. Because the possibility of the preparation of high-performance conversion coatings (CCs) in IFKhANAL-3 chromateless solution, which have protective properties that are no worse than those of chromate CCs according, has been previously demonstrated, the effect of various complexing agents on the oxidation of 1441 alloy and the protective properties of the CCs on it have been further studied. It has been shown that CC-modifying additives adsorb corrosion inhibitors and increase their protective properties.

In the present work, the possibility of using integrated fiber-optic deformation sensors (Bragg’s sensors) to control the state of the fiberglass on an epoxy anhydride hot cure binder is studied. Sensors are located in different layers of the layered plastic reinforced by a biaxial fiberglass cloth. A package has a quasi-isotropic structure. A sample is prepared by the method of vacuum impregnation and it is exposed to the action of water vapor with the relative humidity of 95% at 80°C. It is found that the moisture sorption in the composite occurs by a relaxation mechanism and is accompanied by a nonmonotonic change of swelling deformation in different layers of epoxy fiberglass. The swelling deformations in different layers of fiberglass are detected, their evolution during heat-humidity corrosion is shown, and, based on these data, the working capacity of the system of the measurements of the humid deformations of the fiberglass using for pipe production is confirmed.

The mechanism of aging of plasticized PVC coexposed to several factors—temperature and Aspergillus niger microscopic fungus—is elucidated. Long-term exposure to Aspergillus niger increases electrical insulation resistance, probably because the content of plasticizing additive in the polymer decreases.

The growth of oxide films on the surface of magnesium in 5M NaOH and a borate buffer solution with pH of 11.2 is studied. The thickness of the oxide film on the surface of magnesium reaches about 70 nm in an 5M solution of NaOH and about 50 nm in a borate buffer solution with pH of 11.2 over 120 min. Isotherms of adsorption of 5-chlorobenzotriazole and dioctyl phosphate in a borate buffer solution with pH of 11.2 are obtained. The free energy of adsorption of these compounds is the same, 50.2 kJ/mol.