A. L. Borisova

Reactions in the Cr-SiC system under conditions of ordinary and plasma heating

Progress in new fields of technology is inseparably linked with the formulation of materials possessing specialmechanical and physicochemical properties as well as with the use of protective coatings for improving the quality of parts. A promising direction in research on coatings with special properties is the production of multiphase coatings consisting of mixtures of carbides and silicides of transition metals, in particular chromium. One way of producing mixed carbide-silicide coatings or materials is to utilize the reaction of chromium with silicon carbide.

Composite Ti-Si-C System Coatings

Abstract Composite Ti-Si-C system coatings consist of a siilicide matrix and hard carbide containing inclusions. Plasma spraying of the composite powders of desired composition provides coatings combining the high wear and corrosion resistance with a low friction coefficient.

Reaction of boron carbide with titanium under ordinary and plasma heating conditions

ConclusionsAs a result of an investigation, into the high-temperature solid-phase reaction of boron carbide with titanium under ordinary and plasma heating conditions, it has been established that the reaction, which begins at 1300°C, is slow in its final stage, which is due to the appearance of a zone of porosity and to disturbed contact between the reactants. Because of this, in spite of its being accompanied by an appreciable thermal effect, the reaction fails to proceed to completion under conditions of both continual ordinary heating (to 1600°C) and plasma heating. It is possible to obtain spray-deposited coatings of the required composition (TiC+TiB2) by employing preconglomerated or clad Ti -B4C powders and preheated basis plates.

TRANSITION METAL-NONMETALLIC REFRACTORY COMPOUND COMPOSITE POWDERS FOR THERMAL SPRAYING

The study was intended to establish the thermal spraying effectivity of composite povders consisting of transition metals (chrome, titanium, zirconium etc) and nonmetallic high-melting compounds (silioon carbide, boron carbide, silicon nitride, boron nitride). Coatings of these components interactions products (mixtures of carbides, silicides, and carbosilicides; borides and carbides; nitrides and silicides; borides and nitrides) show high wear and corrosion resistance; the synthesis process is exothermic.

Production of powders for thermal spraying of coatings by mechanical alloying and mechanochemical synthesis

Special features of the production of powders for thermal spraying of coatings by mechanical alloying and mechanochemical synthesis are described.

Producing powders for thermal spraying by mechanical alloying and mechanochemical synthesis

Special features of the production of powders for thermal spraying by mechanical alloying and mechanochemical synthesis are described.

Interface interaction and structural transformation in particles of ceramic and cermet composite powders in flame spraying

The behavior of particles of Al2O3, TiO2, Al2O3 - TiO2, Al2O3 - Ni, ZrO2 - Ni, Al2O3 - Ni- Ti powders in flame spraying has been studied. The interaction between the surface tension forces and the wetting forces has been found to produce either a melt shell around the particles core or drops of the second component on the surface of the core. Subsequently a total or partial capture of drops of the second component melt by the core melt or their separation during the movement within the plasma jet volume are possible. At high particle heating and cooling rates, polymorphous transformations, higher - to - lower oxide transformations and metastable phase fixations in the coating take place. These effects influence the conditions of ceramic powder plasma coating formation and also the properties of the coatings.