The very high capture cross-section of (epi)thermal neutrons by the boron isotope ¹⁰B makes elemental boron and its compounds and composites prospective for serving as materials intensively interacting with neutron irradiation. In their nanostructured form, boron-rich materials reveal properties that improve their radiation-performance characteristics. In this regard, new technologies have been proposed for the synthesis of nanocomposites with matrices of boron carbide B₄C and hexagonal boron nitride h-BN. For the first time, boron carbide-tungsten and hexagonal boron nitride–(iron,magnetite) composites were obtained, respectively, in the form of layered/sandwich structures of components B₄C and W and h-BN nanopowders coated/intercalated with magnetic nanoclusters of iron Fe or magnetite Fe₃O₄. Studying of their chemical/phase composition, structure/morphology, and some other properties leads to the conclusion that the developed B₄C–W and h-BN–(Fe,Fe₃O₄) composites would be useful for solving important problems of boron-based neutron shielding and BNCT (Boron Neutron Capture Therapy), such as attenuating the gamma-radiation accompanying the absorption of neutrons by ¹⁰B nuclei and targeted delivery of ¹⁰B nuclei, as BNCT therapeutic agents, to tumor tissues using control by an external magnetic field, respectively.

Tungsten carbide WC-based materials characterized by high hardness and wear resistance have long been widely used in manufacturing cutting and mining tools. They are alloyed or modified with different ceramic phases to improve operational characteristics further. There are obtained the hard tungsten carbide–cobalt WC–Co and tungsten carbide–titanium carbide–cobalt WC–TiC–Co metal-ceramic alloys ultradispersed powders modified with quasieutectic ceramic alloy B4C–30wt.%TiB2 and complex samples compacted from them. The quasieutectic alloy used as a modifier has almost as high hardness as pure boron carbide. Still, it is characterized by higher electrical and thermal conductivities of several orders of magnitude. Two groups of hard alloys modified with B4C–30wt.%TiB2 were studied: ВK8 grade WC–Co and T30K4 and T15K6 grades WC–TiC–Co. Metal-ceramic composite powders of different concentrations are obtained by chemical synthesis and mechanical dispersion in an attritor. The particle size of chemically synthesized composite powders is ≤0.3 μm, and those obtained by mechanical dispersion are ≤0.8 μm. SPS (Spark-Plasma Sintering) and HTS (High-Temperature Sintering) methods compact these powder materials. Phase composition of the obtained materials, distribution of chemical elements in them, and structural features are investigated by the XRD (X-Ray Diffraction) method and EDX (Energy Dispersive (micro)X-ray) spectrometry and optical and electron microscopies, respectively. Key physical-mechanical characteristics of the received samples, such as hardness, microhardness, and bending strength, are studied. Ultradispersed (≤0.8 μm) metal-ceramic alloys of the WC–Co–B4C–TiB2 system with interesting characteristics have been obtained using the WC–Co hard alloy of BK8 grade as the matrix. A SPS-compacted sample's hardness, microhardness, and bending strength are 93.0 HRA, 3350 kgf/mm2, and 100 kgf/mm2, respectively. Among the WC–TiC–Co system materials, the Т15K6 grade-based hard alloy modified with 15wt.%(B4C–30wt.%TiB2) has the best characteristics with hardness, microhardness, and bending strength of 91.5 HRA, 2900, and 117 kgf/mm2, respectively. A preliminary study of the problem of environmentally safe utilization of tungsten-containing scrap and tungsten waste is also carried out as part of the work. In particular, the tungsten heater waste is treated in hydrogen peroxide, and by adding specific liquid components to the tungsten-containing proper solution in a single utilization–synthesis cycle, the target product – ultradispersed WC–Co hard alloy is obtained.