Effect of the Polyphosphate/Me Molar Ratio in an Aqueous Electrolyte on the Composition of Anodic-Spark Layers at Aluminum Alloys

The manner in which the molar ratio n = [sodium polyphosphate]/[Me cation] in aqueous electrolytes is related to the thickness h and the element content (EC) of anodic layers formed on aluminum and its alloys during electric microbreakdowns (sparks, microarcs) is established. The polyphosphate structure, the electrolyte pH, and the nature and charge of Me cation do not affect dependences of EC and h on n in the case of Mn(II), Pb(II), Mg(II), Zn(II), Ni(II), Y(III), and Eu(III). The film growth mechanism changes with n. The incorporation of P, Me(II), or Me(III) is due to thermolysis of precipitate from electrolyte containing hydrated polyphosphates of Me(II) or Me(III), the thermolysis occurring at the anode under the action of electric breakdowns.     

Optical Properties of ZrO2–Containing Anodic Coatings on Aluminum

Anodic oxide coatings (AOC) formed at the potentials of spark breakdowns in aqueous solutions of potassium hexafluorozirconate (K₂ZrF₆) contain up to 36 wt.% of Zr. The modification of ZrO₂ in AOC is tetragonal. The reflection coefficients of AOC have been measured in the range 430–670 nm. After UV irradiation for a few hours the reflection coefficient decreases by several percent. The treatment of AOC in a solution containing F^– and [Fe(CN)]^3– ions leads to a change in the aluminum and zirconium concentrations in the surface layer and to an increase of the AOC reflectivity.     

Stability and Instability of Steady States for a Branching Random Walk

Methodology and Computing in Applied Probability - We consider the time evolution of a lattice branching random walk with local perturbations. Under certain conditions, we prove the Carleman type...     

On Composition of Anodic-Spark Coatings Formed on Aluminum Alloys in Electrolytes with Polyphosphate Complexes of Metals

Anodic layers containing M(II) phosphates, e.g., Mg₃(PO₄)₂, Mn₂P₂O₇, Mn(PO₃)₂, and NaZnPO₄, were obtained.     

Deposition,composition, and activity in CO oxidation of anodic layers with platinum on aluminum and titanium

Pt + TiO₂/Ti(Al) and Pt + CeO₂ + ZrO₂ + TiO₂/Ti composites were formed by plasma electrolytic oxidation and their surface composition and catalytic activity in CO oxidation to CO₂ were studied.     

Transformations of diepoxy derivatives of limonene in homogeneous acidic media

Transformations of diepoxy derivatives of limonene under conditions of homogeneous acid catalysis were studied, and their results were compared with those obtained over heterogeneous catalysts. A number of previously unknown compounds were isolated. The most possible transformation pathways were analyzed by computer simulation using molecular-mechanics and quantum-chemical methods.     

Manganese-Containing Anodic Layers on Titanium

Data on formation of anodic layers containing MnTiO₃, -Mn₂TiO₄, Mn₂O₃, Mn₃O₄, and Mn₃(BO₃)₂ on titanium from aqueous electrolytes at sparking voltages are presented.     

Transformations of Isocaryophyllene Diepoxide under Conditions of Homogeneous and Heterogeneous Acid Catalysis

Transformations of isocaryophyllene diepoxide (an isomer of widely spread natural sesquiterpene) were studied in various acidic media under conditions of homogeneous and heterogeneous catalysis. A number of previously unknown compounds were thus obtained. The experimental data were compared with the results of molecular-mechanics and quantum-chemical simulation of the most probable transformation paths.     

Use of spectral methods to study branching processes with diffusion in a noncompact phase space

Moscow State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 88, No. 1, pp. 25–30, July, 1991.