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The degradation of nanodimensional platinum catalysts in concentrated phosphoric acid and the related changes in the kinetics of cathodic oxygen reduction have been studied in the course of accelerated corrosion tests. The results of structural and electrochemical investigations showed that the stability of such electrocatalytical systems substantially depends on the type of supporting carbon and the metal phase composition.

The co-reduction of cobalt and molybdate ions with dimethylamine borane in pyrophosphate solutions is shown to produce Co-Mo-B alloy coatings. Molybdate is reduced concurrently with cobalt to metal forming a solid solution in cobalt matrix with a hexagonal lattice. The alloy deposits have a pronounced [001] texture with the easy magnetization direction normal to the coating surface. The composition of alloys is heterogeneous in their thickness. The alloys contain cobalt and molybdenum hydroxide admixtures, as well as intermediate products of molybdenum reduction, in the superficial layers.

The structures, chemical states of elements, and catalytic activities of Ni-Mo-B alloys with different molybdenum contents, which were obtained by catalytic electroless reduction of metal ions, were studied. The rates of the partial reactions (heterogeneous hydrolysis of dimethylamine borane, reduction of nickel ions, and evolution of molecular hydrogen) were found to make a bell-shaped curve when plotted versus the concentration of molybdate ions in solution.

The effect of the introduction of Al2O3 and SiC particles into the base chrome-plating sulfate-oxalate Cr (III) bath on the electrochemical characteristics of chromium deposition, as well as the structure and mechanical properties of deposits, is studied. It is shown that Al2O3 particles are incorporated only into the surface film and are not detected in the bulk of the coating. Particles SiC are incorporated into both the surface film and the deposit. Introducing the particles into the bath makes the cathode polarization at a fixed current density, as well as the current efficiency and the bath throwing power, increase.

The effect of surface oxidation on the corrosion behavior of amorphous Fe70Cr15B15 alloys in the acidic sulfate media with constant ionic strength is studied. It is found that the main factor determining the electrochemical behavior of alloy is not only the elemental composition of the surface, but primarily, its chemical composition. Surface nanooxide films have the strongest effect. Films with spinel structure are most corrosion-resistant. Oxidation has an effect predominantly on the anodic process.

Morphology, phase composition, and chemical state of the elements in the superficial oxide layers on Ni-Mo-B alloy coatings obtained by chemical catalytic reduction of metal ions with dimethylamine borane are studied. The coatings were oxidized at 600°C and an air pressure of 2 × 104 Pa. The difference in the growth morphology of the oxide layers on freshly deposited coatings and those preliminarily heated in a vacuum is revealed. The oxide films are composed of the MoO2, Mo2C, as well as amorphous and nanocrystalline NiO, phases. Electron Auger spectroscopy has shown that boron in the form of B(OH)3 is present in segregations along spheroid boundaries. Upon the oxidation of freshly deposited coatings, pits are formed as a result of the “explosive” removal of water vapors from the coating.

Kinetics of the high-temperature oxidation of Ni-Mo-B alloys containing 11 wt. % Mo (obtained by means of chemical catalytic reduction with the use of dimethylamine borane) is investigated. A strong dependence between the oxidation rate and the sublimation of volatile compounds on the prehistory of deposits is disclosed. Freshly obtained deposits exhibit an anomalous short-term weight loss caused by the “explosive” character of the removal of water vapors, evolved as a result of the reduction of molybdenum and boron oxides with hydrogen at heightened temperatures. Preliminarily heating the specimens in a vacuum decreases the intensity of or completely eliminates the anomalous phenomenon. When oxidizing the coatings in air at 600°C, two processes take place, namely, the oxidation of the coating components (a growth of the oxide layer) and the sublimation of volatile compounds.

The effect of temperature and solution components of the chemical catalytic reduction on the composition of Ni-W-B alloy coatings is studied. The x-ray photoelectron spectroscopy in combination with the layer-by-layer profile analysis is used to determine the chemical state of elements and the composition of surface and bulk layers of the coatings containing 28 and 1.8 wt % (10 and 12 at. %) tungsten and boron, respectively. The surface of such coatings is shown to contain up to 90 and 80 at. % reduced nickel and boron, respectively. The deposits have amorphous structure. The effect of thermal treatment conditions on the structure and microhardness of the coatings is investigated. The coatings with a tungsten content of 10 at. % are shown to be nonmagnetic.

The distribution of elements in Ni–Cr alloy deposits is studied with the use of x-ray photoelectron spectroscopy and electron Auger spectroscopy. Nickel is shown to catalyze the deposition of chromium, while chromium catalyzes the reduction of oxalates to carbon. The alloys have nanocrystal fcc structures based on nickel lattice. At a high chromium content (88 at. %), a phase with hexagonal lattice forms.

The hydrogen content in electroplated chromium layers and multilayer nickel–chromium coatings applied by periodic current from sulfate–oxalate baths is discussed. Chromium electroplating at periodic and pulsed currents is found to increase the hydrogen content to 54 cm3 /g as compared with 24 cm3 /g for chromium deposits obtained in a direct-current mode. The hydrogen content in multilayer Ni–Cr coatings is found to be substantially lower. As shown by mass-spectrometric studies, hydrogen preferentially absorbs in chromium layers. The peculiarities of concurrent hydrogen evolution and chromium deposition giving supersaturated solid solutions are discussed.

The chemical state of elements and the composition of surface and bulk layers of Ni–B coatings with the volume concentration of boron of 3.7 and 27.1 at. % obtained by electroless catalytic reduction are studied with x-ray photoelectron spectroscopy combined with layer-by-layer profile analysis. Up to 90% of nickel and 80% of boron are shown to be reduced on the surface of the coatings. The effect of the conditions of heat treatment in a vacuum and in air on the composition of the surface layer is analyzed. The original nonuniformity of the in-depth distribution of the elements is found to be most of all affected by heating in air at a temperature of 700°C that provides the surface formation of a B2O3 oxide layer containing no nickel. A stabilized composition of the alloys is observed at a depth of 10 to 60 nm depending on the conditions of heat treatment.

The chemical composition of chromium deposits obtained from acidic (pH 1.5 to 1.7) chromium (III) oxalate-sulfate solutions was studied with the use of x-ray photoelectron spectroscopy. From the solutions containing more than 100 g/l Cr2(SO4)3·6H2O, an amorphous carbide close to Cr23C6 with inclusions of metallic chromium clusters is deposited on the cathode. From less acidic solutions poorer in chromium, metallic chromium is deposited.

The kinetics of individual and concurrent discharge of nickel and chromium ions from oxalate–sulfate solutions is studied. At a high cathodic potential (–1.2 V), the process of nickel deposition is sharply decelerated due to the surface passivation of the cathode with nickel oxides and the adsorption of organic products. During the coreduction of the ions with the formation of an alloy, the discharge rate of nickel ions is sharply decreased and the deposition of chromium is accelerated, compared to the electrodeposition of individual metals. The phenomenon observed is accounted for by a sharp decrease in the rate constant of the electrochemical reaction of nickel discharge on the surface of an alloy.

Based on the data of x-ray photoelectron spectroscopy and resistometry, a possibility of the electroless reduction of iron from solutions containing hypophosphite ions as reducing agent, and glycine as ligand is shown. Some regularities of the deposition of iron coatings are determined.