Sergey F. Tikhov

The three-dimensional microporous structure of alumina synthesized through the aluminum hydrothermal oxidation route

The structural properties and porosity of a γ-alumina sample prepared by the hydrothermal treatment of powdered aluminum were investigated using techniques of nitrogen adsorption, mercury porosimetry, and electron microscopy. The information available from each technique is used to present a more complete picture of the three-dimensional pore structure of this sample, in terms of size, shape, distribution, crystallographic orientation and accessibility of pores.

Synthesis and properties of highly porous MeOX/Al2O3/Al composites (Me = Mg, Ca, La, Ti, Al)

The influence of various oxide additives, such as CaO, MgO, La2O3, TiO2, and alumina on the reactivity of aluminium particles during their hydrothermal oxidation as well as on the thermal decomposition of hydroxides during the composite preparation has been studied. For some promoters, these additives were found to affect the crushing strength of composite granules and their microporous structure.

Synthesis of alumina through hydrothermal oxidation of aluminum powder conjugated with surfactant-directed oriented growth

Sergey F. Tikhov, Yulia V. Potapova, Vladislav A. Sadykov, Vladimir B. Fenelonov, Ivan V. Yudaev, Olga B. Lapina, Aleksey N. Salanov, Vladimir I. Zaikovkii, Galina S. Litvak Addresses for Correspondence: S.F.Tikhov, Boreskov Institute of Catalysis, Av.Lavrentieva,5, Novosibirsk, 630090. Russia; tikhov@catalysis.nsk.su; Tel: 007 383 3308764; Fax: 007 383 3308056

Porous Al2O3/Al metal ceramics prepared by the oxidation of aluminum powder under hydrothermal conditions followed by thermal dehydration: III. The reactivity of aluminum, the reaction mechanism of its oxidation with water vapor, and the microtexture of cermets

The macrokinetics of aluminum oxidation under hydrothermal conditions at 150–250°C and water vapor pressures of ∼0.5–4.5 MPa was studied. The apparent kinetic characteristics of the process were determined. The diffusion of water through the layer of a hydrated product was found to be a rate-limiting step. It was found that diffusion coefficients for various aluminum samples differed by almost two orders of magnitude; the main reaction steps were revealed. Changes in the texture of aluminum oxide in cermets in the course of the hydrothermal oxidation reaction were analyzed. This texture was found to depend on the ratio between the specific rate of the oxidation reaction and the rate of aging of the oxidation products under hydrothermal conditions.

Kinetics of Aluminium Powder Oxidation by Water Vapor at Moderate Temperatures

For the first time the detailed kinetics of aluminium oxidation by water vapor at 150-250 °C range and steam pressure of 500-5000 kPa was investigated. A «shrinking sphere» model was used for kinetic description. The effective kinetic parameters, such as the apparent activation energy and the reaction order were estimated.

Porous Al2O3/Al metal ceramics prepared by the oxidation of aluminum powder under hydrothermal conditions followed by thermal dehydration: IV. Effect of oxide additives on the composition and texture characteristics of MOx/Al2O3/Al composites

The synthesis, structure, and texture of metal ceramics based on Al2O3/Al with powdered oxide additives (CaO, MgO, Al2O3, La2O3, and TiO2) were studied. Analytic expressions were derived to relate the main macroscopic characteristics of the composites.

Porous Al2O3/Al metal ceramics prepared by the oxidation of aluminum powder under hydrothermal conditions followed by thermal dehydration: I. Composition and macrocharacteristics of composites

The macrotexture and mechanical properties of porous Al2O3/Al metal ceramics prepared by the hydrothermal treatment of aluminum powder in a closed space are studied using gravimetry, pycnometry, mercury porosimetry, and scanning electron microscopy. Analytical expressions that relate the porosity, density, and mechanical strength of parent materials and final products to the composite synthesis conditions are derived.