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Multicomponent coatings on 20 and Kh18N10T steels formed by the method of vacuum activated diffusion saturation are studied. A mixture of B4C, Al, Ni, Si, Cr, and C powders is used as the saturating medium. A thermodynamic analysis of reactions that accompany the titanizing process. Metallographic, micro-hardness, and X-ray diffraction data are discussed. The cavitation–erosion resistance of multicomponent coatings on steels is studied. It is established that these coatings improve the resistance of steel 20; the destruction rate being the same for both 20 and Kh18N10T steels.

This paper reports on the results of investigations of the development of high-temperature protective coatings on carbon-carbon materials, which are formed through vacuum activated diffusion saturation under conditions of liquid media and self-propagating high-temperature synthesis. The results of testing of the protective coatings in air at temperatures in the range 1600–1950°C are presented.

Complex carboborosilicide and oxide coatings on carbon materials prepared by vacuum activated diffusion impregnation predominantly through a liquid phase, vacuum fusion, and enamelling are studied. It is established that coating formation from the vapor phase hardly reduces the original porosity of carbon materials. The complex protective coatings developed that are formed by vacuum activated diffusion impregnation through a liquid phase lead to a reduction in the original porosity and gas permeability of carbon materials thereby increasing their high-temperature strength and heat resistance at elevated temperatures. It is shown that higher heat resistance in the temperature range 1800–2000 °C is provided by multilayer coatings based on carbides and borides of silicon, titanium and zirconium, borosilicides of tungsten, hafnium, molybdenum, and also oxides of silicon, aluminum, zirconium, and hafnium. It is established that the protective properties of coatings depend markedly both on their composition, structure, preparation method and on the form of the original carbon materials.

An investigation was carried out into the effect of porosity in the range 2–46% and grain size in the range (5–140)·10−6 m on the mechanical properties of boron carbide. It is shown that the level of mechanical properties of boron carbide produced by hot pressing from powders synthesized from the elements is 1.5 times higher than that of boron carbide produced by other methods. Increasing the porosity of boron carbide to 46% decreases its strength by a factor of six or seven. Increasing the grain size to 140·10−6 m has the same effect. An analysis is made of equations describing the dependence of the mechanical properties of boron carbide on porosity and grain size. The constants of these equations have been determined.

1. A study was made of the densification kinetics of B4C in hot pressing at temperatures in the range 1800–2200°C under a pressure of 225 kgf/cm2. 2. The effects of applied pressure in hot pressing at a temperature of 2100°C were investigated over the range 75–375 kgf/cm2. 3. It is demonstrated that the densification of boron carbide is controlled by a process leading to non-linear creep, whose rate is a function of the square of stress.