— A new technique has been proposed for TiO 2 synthesis via oxidative hydrolysis of TiN powder. We have examined the effect of factors determining the rate of TiN dissolution (temperature, concentration, and nature of the oxidant) on the phase composition and particle size of resulting TiO 2 powders and assessed the photocatalytic activity of the synthesized powders in comparison with commercially available photocatalysts.

The photocatalytic activity of crystalline titania nanopowders synthesized in a stream of ultrahigh-frequency discharge oxygen-containing low-temperature plasma was assessed. To this end, oxidation of an organic dye was carried out in UV-irradiated aqueous suspensions of TiO2 at different concentrations and varied irradiation times.

The electrolytic deposition of composite copper-based coatings with an ultradispersed phase (TiN or Al2O3) was studied. Conditions for obtaining coatings with the maximum microhardness were determined.

The interaction of ultrafine and coarse powders of titanium nitride with a chromium electrolyte at various temperatures was considered with the aim to prepare a composite electrolyte. It was found that upon interaction with chromic acid, TiN is converted to titanium dioxide, which is present in solution in the form of a highly dispersed precipitate. It was shown that the dependence of the content of the components of the composite electrolyte on the heating time, passing through a maximum, reaches an equilibrium state that is reached more quickly in the case of higher temperatures and finer powder.

The ultradisperse powders of boron nitride with the mean particle size of 5.3–66 nm showed marked anisotropic deformation of the crystal lattice as a result of the structural stresses which are caused by the dimensional factor and are distributed nonuniformly through the volume of the particle.

In the hydrogen reduction of TiCl4, and thermal decomposition of Mo(CO)6 in a stream of shf discharge nitrogen plasma the main reaction products are titanium nitride and molybdenum. The impurity elements in the composite (carbon and oxygen) react with the titanium nitride, forming the titanium oxycarbonitride TiNxOyCz (where x + y + z = 1, y < 0.10, and z < 0.05). The formation of nitride particles takes place before the instant of full pyrolysis of Mo(C0)6, and molybdenum therefore does not cover them, but condenses in the form of free spherical particles whose mean size is about half that of the particles forming during the pyrolysis of the carbonyl without a TiCl4 addition to the reactor. A characteristic feature of the resultant fine molybdenum-nitride composite powders is a high uniformity of distribution of Ti and Mo in them.

Vacuum annealing at a temperature above 900°K enables the specific surfaces of very fine loose tungsten and molybdenum powders to be varied in a wide range. The vacuum sintering of compacts pressed from very fine (particle size less than 0.05μm tungsten and molybdenum powders is accompanied by severe cracking. In the hot pressing of very fine Mo and W powders produced by the pyrolysis of carbonyls in a stream of high-temperature plasma, a specimen density close to theoretical is reached at 1600°K i.e., at a temperature not less than 400°K lower than the sintering temperatures of powders of particle size more than 1 μm. Sintering lowers the amounts of carbon and oxygen in Mo and W by more than half compared with the starting condition.

AbstractDurch Azotierungen von Cr‐Mn‐Schmelzen bei 800‐1100°C werden feste Lösungen der Zusammensetzungen Cr0,50Mn0,50N0,92, Cr0,60Mn0,40N0,89, Cr0,70Mn0,30N0,87, Cr0,80Mn0,20N0,94, Cr0,90Mn0,10N0,98 und Cr0,95Mn0,05N0,98 erhalten; in allen Fällen liegen Gitter‐Strukturen vom NaCl‐Typ vor.