Stanislav P. Gordienko

Reaction of Titanium with Boron Nitride under Self-Propagating High-Temperature Synthesis Conditions

We have used the ASTRA computer program for thermodynamic analysis of the chemical reaction of mixtures of titanium with boron nitride in the composition range of 1-26 mass% BN under adiabatic conditions. We have calculated the adiabatic temperatures, the heat change, and the concentration of the reaction products. We have established that under self-propagating high-temperature synthesis (SHS) conditions, we can obtain alloys of titanium with titanium nitride and monoboride and alloys of titanium nitride with titanium borides. Experimental synthesis of the alloys under SHS conditions confirm the thermodynamic analysis results.

Thermodynamic Characteristics of Iron Subgroup Borides

Standard enthalpies of formation and atomization Cpº(298.15 K), Sº (298.15 K), Hº (298.15 K) ― Hº(0 K) and the temperature dependence of the heat capacity in the range 298.15 K-Tmp have been determined for iron subgroup borides.

Role of Nitrogen during Oxidation of Titanium Diboride in Air

We have studied the effect of nitrogen on oxidation of titanium diboride in air. By thermodynamic analysis of the reaction in the TiB2 – air system, we have established that the oxide film is layered. When the air content in the system is less than 50 mass%, the predominant reaction products are boron and titanium nitrides, which suggests a special role for nitrogen during oxidation.

Thermodynamic modeling of chemical reactions in the heating of stainless steel H18N15 with Cr2C3, MoS2, and carbon additions in a hydrogen atmosphere

A thermodynamic modeling of the chemical reactions occurring during the heating of H18N35 stainless steel with Cr3C2, MoS2 and C additions in a hydrogen atmosphere at the 1000–1800 K temperature interval has been conducted. The formation of CrS, MoS2, Cr7C2, and the (Cr0.66Fe0.34)2.52C double carbide with the emission of H2S, CH4, C2H2, and the components of the steel into the gaseous phase at 1600 K (or above) has been detected. The results of the thermodynamic modeling are confirmed by the experimental data.

Thermodynamic Analysis of High-Temperature Oxidation of Material in the Cr – TiB2 – TiSi2 System in Air

We have carried out a thermodynamic analysis of the chemical processes in the system Cr – TiB2 – TiSi2 at temperatures of 1400 K to 1800 K in air. We have established that titanium diboride plays the role of a protective layer while titanium disilicide is the substrate for a layer protecting from reaction with air.

Thermodynamic Modeling of Reactions in the System SiO2 ― TiO2 ― C when Excess Nitrogen is Present

We have used the thermodynamic modeling method to study reaction in the system SiO2 ― TiO2 ― C when excess nitrogen is present. We have established that at temperatures of 1200-1800 K, one can obtain a composite material: a mixture of silicon and titanium carbonitrides, the content of which is determined by the composition of the starting mixtures and the compositions of which are determined by the synthesis temperature. The thermodynamic modeling data are supported by the results of chemical and x-ray analysis of the reaction products in the system SiO2 ― TiO2 ― C in a stream of nitrogen.

Interaction of Boron Carbide with Nickel Oxide

Thermodynamic methods and x-ray analysis have been applied to the chemical interactions in 0.9625 B4C + 0.05 NiO + 0.0375 C, B4C + NiO, B4C + 4 NiO + 3 C mixtures; stages occur in the processes there that correspond to various temperature ranges. It is found that NiB always contains small amounts of lower borides, whose quantity does not exceed 2 mass% when the synthesis conditions are optimal.

Atomization Enthalpies for Compounds of Rare-Earth Metals with Subgroup Vb Elements

The comparative method of evaluating standard atomization enthalpies for binary compounds has been extended to rare-earth metal compounds Ln ― X (X = N, P, As, Sb, Bi). A correlation equation has been derived for the comparative method. The atomization enthalpies of compounds that have not been investigated can be estimated with an error of ±5%.