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Friction units of modern power turbines require the use of special materials with stable and low coefficients of friction under extreme conditions. Antifriction carbon-graphite materials, in particular isotropic pyrolytic carbon, are most successfully used for these purposes. Isotropic pyrolytic carbon was found to have a lower friction coefficient and wear rate than ATG-S antifriction graphite. The difference in the tribological behavior of materials was proposed to be caused by various destruction mechanisms based on an analysis of the microstructure and fractograms of wear traces. Also, isotropic pyrolytic carbon was shown to decrease the wear rate and friction coefficient with increasing density.

The investigating results are given on the process parameters' influence on the phase and structure formation in the course of the B4C based materials' reactive sintering under the Si molten presence. The interaction of the B4C particles and carbon with the molten silicon was regarded during the reactive sintering. The negative effect of the B4C particles' dissolution in the molten silicon within the reactive sintering was noticed. The methods to raise the boron carbide particles' content in the ceramics based on the reactively sintered boron carbide were discussed.Ill. 10. Ref. 24. Tab. 1.

In this paper we studied the evolution of shock compression waves in hot-pressed ceramics based on boron carbide and silicon carbide at a maximum compressive stress of 32 and 34 GPa, respectively, to determine the possible contribution of relaxation processes to the resistance to high-rate deformation. At a change in sample thickness from 0.5 to 8 mm, an appreciable decay of the elastic precursor was observed in boron carbide while an insignificant anomalous growth of the elastic precursor with a sample thickness was observed in the experiments with silicon carbide samples of various thickness. The measured value of the Hugoniot elastic limit of samples with a thickness of 8 mm was σHEL = 17.2 ± 1.3 GPa for boron carbide and σHEL = 15 ± 0.1 GPa for silicon carbide.

Shrinkage curves of alloys formed from the WC–8% Ni hard-alloy mixture activated by introducing 10% nanodimensional WC and charge without the additive in a temperature range of 800–1500°C are presented. The pore structure and microstructure of the samples at various stages of sintering are investigated. The peculiarity of densification of the modified alloy, which consists in the shift of the shrinkage curve into the lower temperature region, is revealed. This makes it possible to lower the temperature of the vacuumcompression sintering of alloy, form a finer grain structure, and attain high characteristics of hardness–wear resistance without worsening the strength characteristics. Physicomechanical properties and microstructure of compression-sintered samples made of VN8M activated alloy and standard VN8 alloy without additives are investigated.

The shock compression wave profiles in three modifications of boron carbide ceramic are studied in the compressive stress range 3–19 GPa. The Hugoniot elastic limit and the spall strength of the materials are determined. It is confirmed that the spall strength of high-hardness ceramic changes nonmonotonically with the compressive stress in a shock wave.

The results of measurements of shock compression wave profiles for three modifications of carbide ceramics in the stress range 3–19 GPa are presented. The dynamic elasticity and spall strength limits of the materials are determined. It is shown that these characteristics are sensitive to specific characteristics of reaction-sintered ceramics related to technological parameters of the process of their manufacturing. It is confirmed that the spall strength of highly rigid ceramics varies nonmonotonically with increasing compression stress in the shock wave.

The evolution of a shock compression wave in SiC ceramic is measured for determining the possible contribution of relaxation processes to the high-rate straining. No appreciable decay of the elastic precursor and other features of stress relaxation are revealed when the sample thickness changes from 0.5 to 8.3 mm, and the evolution of the compression wave corresponds to a simple wave. The measured values of the Hugoniot elastic limit (σHEL = 8.72 ± 0.17 GPa) and spall strength (σsp = 0.50–0.62 GPa) with allowance for the density of the ceramic are in conformity with the available data.

Boron-containing refractory oxygen-free compounds are used extensively for creating materials (ceramics) for different purposes. Systems based on them, promising for creation of functional and structural ceramics (coatings) for extreme service conditions, are analyzed.

Technology is developed for manufacturing dispensing nozzles made of zirconium dioxide. Test-industrial batches of objects, manufactured using separate and combined stabilization of ZrO2, are produced and tested under industrial conditions. Dispensing nozzles differ in open porosity. The service behavior for the objects developed and imported analogs is compared. The efficiency of using dispensing nozzles made of zirconium dioxide with porosity less than 12% during operation in a CBCM is demonstrated.

Technology is developed for preparing refractory components made of partially stabilized zirconium dioxide using an isostatic compaction press. Technology is provided for manufacturing dispensing nozzles using combined and separately stabilized zirconium dioxide, and also indices of the refractories obtained and imported materials are compared.

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