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FeCrWMoC metallic glass (MG) is synthesized in the form of coatings by electric spark treatment in grain media consisting of individual components. It is demonstrated that the amorphous phase fraction in the composition of the coatings increases with the time of the granule treatment increasing to 100–150 min. The proposed approach offers the potential for the one-stage synthesis of MG in the form of coatings in the automatic mode.

Crystalline FeWMoCrBC electrode materials were prepared by conventional powder metallurgy. Metallic glass (MG) coatings were produced by electrospark deposition onto AISI 1035 steel in argon atmosphere. X-ray diffraction and scanning electron microscopy verified the amorphous structure of the as-deposited coatings. The coatings have a thickness of about 40 microns and a uniform structure. The results of dry sliding wear tests against high-speed steel demonstrated that Fe-based MG coatings had a lower friction coefficient and more than twice the wear resistance for 20 km sliding distance with respect to AISI 1035 steel. High-temperature oxidation treatment of the metal glass coatings at 1073 K in air for 12 h revealed that the oxidation resistance of the best coating was 36 times higher than that for bare AISI 1035 steel. These findings are expected to broaden the applications of electrospark Fe-based MG as highly protective and anticorrosive coatings for mild steel.

Thermostable monodisperse nanoparticles of anatase with a diameter of 35–50 nm doped with tungsten were obtained by the method of hydrothermal synthesis. It was found that the temperature of the phase transition from anatase to rutile decreases from 905 to 650°С with the increase in the content of tungsten oxide from 0.35 to 4% in the precursor. Diffuse reflection spectra of the synthesized nanoparticles were obtained, and the values of the band gap were determined. The band gap varies with changes in tungsten content from 3.15 eV for pure anatase to 2.91 eV for TiO2/WO3(4%), leading to an increase in the optical absorption in the visible and the ultraviolet regions.

Electrospark deposition was employed to clad WC-10%Co, W/C1.6-10%Co, and W/C0.5-10%Co hard alloys on steel 1035, and the tribological properties of the coatings obtained were examined. The influence of the W/C ratio in the electrode materials on the decarburization of tungsten carbide was studied. It is shown that the degree of tungsten carbide degradation can be reduced by increasing the concentration of carbon in the WC-Co electrode materials, and also that the WC decarburization reaction is reversible on annealing. Coatings deposited using new electrode materials with an excess of carbon (W/C0.5) and/or tungsten (W/C1.6) have increased microhardness and improved frictional characteristics compared with the conventional coating.

The structure and properties of coatings based on WC-Co alloys containing additives of 1% - 5% aluminium oxide and 2.5% - 4.5% carbon were investigated. The coatings had a nanocrystalline structure. Depending on the duration and frequency of the discharge pulses, the ratio between WC and W2C in the coatings was different. The additives in the hard alloy allowed us increase the microhardness and wear resistance of the coatings by a factor of 2 - 3 in comparison to coatings created using a conventional WC-10%Co alloy.

In the electrospark deposition (ESD) of WC-Co materials on low carbon steel, tungsten carbide (WC) decarburization is observed. The use of an inert atmosphere (argon) does not eliminate the problem of tungsten carbide decarburization during electrospark processing. The effect of the carbon concentration of electrode materials on the phase composition and mechanical properties of WC (10 wt% of Co) ESD coatings has been investigated in this work. The introduction of additional carbon (graphite) in the electrode material on the basis of the WC-10%Co leads to an increased amount of WC in the obtained coatings and thus improves their wear resistance.

Experimental evidence is presented that the growth of tungsten whiskers during CO reduction of NiWO4 follows the vapor-liquid-solid mechanism. A liquid phase appears at 940°C owing to the melting of NiWO4-Na2WO4 eutectic regions which seem to result from the segregation of sodium impurities present in the reagents used. The presence of the liquid phase ensures comparable rates of Ni and W liberation from the crystal lattice of nickel tungstate, leading to the formation of α-W + NiW two-phase regions. The directional growth of tungsten whiskers during further CO reduction of the tungstate melt is associated with W deposition on the growth surfaces of α-W single crystals in the two-phase regions.

The microstructure and phase composition of a copper foil subjected to single low-voltage discharges of different duration and power have been studied. It was found that the grain size decreases from 200 μm to 10 nm with approaching the center of the discharge-affected zone. The electron-microscopic examinations showed that the compounds formed by electrode materials and oxygen were regularly distributed depending on the distance from the center of the discharge-affected region.