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バジルキフ オレグ
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305-0047 茨城県つくば市千現1-2-1 [アクセス]
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研究内容

Keywords

ceramic engineering, nano-engineering, nano-composites, spark plasma sintering, reactive consolidation, flash sintering, flash SPS, nano-structured composites, nano-powders, nano-ceramic, hard ceramic, tough ceramic, flexural strength behavior, ultra-high elevated temperature strength, dynamic toughness, highly ordered nano-scale structure, self-assembled magnetite-chitosan nanostructures, boron carbide, boron suboxide, titanium diboride, tantalum boride, tantalum carbide, niobium boride, niobium carbide, zirconium boride, silicon carbide,vanadium diboride, zirconium oxide

The request in new multipurpose ceramic for ultra-hight temperature applications, able to act as plasma-facing parts in fusion reactors as far as a special engine & vehicle protection for aerospace cause the worldwide demand in new class of light-weight ceramic composites with incredibly high strength, sufficient balance between high toughness & hardness, ultra-hardness and high-modulus. In NIMS Dr. Oleg Vasylkiv conducting research in chemical and structural engineering of ultra-hard & ultra-strong boron-rich ceramic composites. Non-Catalytic Facile Synthesis of superhard zero- and two-dimensional B13C2 nanostructures. This B13C2 nanoflakes shows high concentration of (1 0 1) type twinning which enhance the toughness of bulk ceramic. This engineered nanostructure boron carbide later shows great potential in the demand of extreme mechanical application, particularly in the construction of complex hierarchical structure nanocomposites. Deep analysis of novel highly ordered nano-scale structure of green-lipped mussel perna canaliculus been performed. The three-dimensional highly ordered nanostructure framework allows understanding the complex growth mechanism and serves as a guide to biomimetic design of artificial nacre-like, high strength, tough composites. Dr. Vasylkiv has combined the merits of powder chemical synthesis, design of artificial nacre-like, high strength, tough composites, Electric Current Activated Processing Techniques and of processing strategies for the design of technologies, applied on powder body with establishing morpho-structural and compositional features, which lead to fabrication of bulk multi-functional high-temperature ceramics within reactive & non-reactive approaches. Currently been confirmed that high-temperature (RD-ECAST) multilevel design of composites of MeIV–VB2, MeIV–V carbides & carbo-borides, nitrides and carbo-nitrides is beneficial in strength increase, elasticity & HT plasticity resulting in improving both room and high-temperature performance. Ultra-high temperature (UHTC) bulk non-oxide and oxide ceramic show excellent properties controlled by composition, grains and by grain boundaries. They are composites where grains and boundaries are the ‘components’. The concept of ‘multilevel design’ from nano to macro levels and concept ‘composite within a composite’ are emerging. Engineering of bulk B13C2, B6O, B4C–TiB2, TiB2–B, B4C–TaB2, B6O-B4C, TiB2–NbC, ZrB2–TaB2, NbB2 composites with unique structure, strength, hardness and toughness by combining the merits of powder synthesis, Electric Current Activated Processing Techniques (ECAST) and of processing strategies of establishing morpho-structural and compositional features, for fabrication of multi-functional UHTC. Reaction-driven spark plasma sintering technique (RDSPS) allows generation of unique bulk high-temperature ceramic composites of practical size and unchallengeable combination of thermo-mechanical properties. Hard and tough BaCb-(BxOy/BN) composites with 3D mesh-like lamellar grain-boundary structure by reactive SPS. There is a growing interest in lightweight covalent ceramics containing B, Ti, Al, C, O and N, which show high stability, chemical resistance, exceptional hardness to specific weight ratio & unique high temperature strength at elevated temperatures. The complex relation between SPS consolidation conditions, features of B4C (B13C2) ceramics and static and dynamic mechanical properties of consolidated ceramics been analyzed. Six-time improved dynamic toughness of massive BaCb-(BxOy/BN) ceramics 6.73 to 35.9 MJ/m2 by structural & GB engineering under RD-SPS conditions. Structural and GB engineering leads to increase in strength, meaning that both strengthening and toughening been activated during consolidation of boron carbide based monoliths by the RD-SPS. We SPSed a B4C–TiB2 system where TiB2 served either as a matrix and a reinforcement phase with stiff covalent skeleton of B4C. This ceramic exhibited RT strength of up to 0.9 GPa with increasing to 1.1 GPa at 1600 °C and 3.8 GPa at 1800 °C. Highly stoichiometric multilayer pentagonal star-shaped only covalent B6Ox (x > 0.85) powder been synthesized. The B6O-based composites are solving the problem of monolithic boron suboxide densification, as the oxygen deficiency in the rhombohedral cell at the 6c position; (x in B6Ox) affects the ‘sinterability’ of as-synthesized boron suboxide powders. B6O bulks exhibit 42 GPa Vickers hardness at 100 N load. The effect of specific star-shape on the high-temperature strength of boron suboxide been investigated. The increase in strength was associated with unique microstructure of B6O grains, and suggests GPa strength at above 1800 °C. Further increase in strength for boron suboxide bulk was associated with grain structure deformation prior to temperatures for B6O dissociation at 1800 °C. In addition the orthorhombic phase AlB24C4, the most compact with the closest packing to ideal cubic one among the Al-B-C phases containing 12-type icosahedra been obtained via RD-SPS. Ternary single-phase high-entropy TaZrNb carbide was obtained using reaction driven-ECAST. Phase analysis and lattice parameter measurements using x-ray diffraction showed multi-stage formation of the single-phase high-entropy-type carbide with lattice parameter of 4.535 Å. This is expected to be also true for other multicomponent high-entropy carbides, as metal atoms have a different diffusivity in newly formed phases. Flexural strength of TaZrNb carbide showed a peak of strength at 1600 °C. Above this temperature, carbide phase fractured in a different manner and been accompanied with decrease in strength and elastic modulus. High-strength boron-based eutectic composites via in situ SPS. B4C-TaB2 eutectic composites by spark plasma sintering. High-strength TiB2-TaC ceramic composites prepared using reactive spark plasma consolidation. Mechanical properties of SiC–NbB2 eutectic composites by in situ spark plasma sintering. High-temperature reactive spark plasma consolidation of TiB2-NbC. Synthesis of iron oxide nanoparticles with different morphologies by precipitation method with and without chitosan addition. B4C-VB2 eutectic ceramics by spark plasma sintering. Bulk Ti1-xAlxN nanocomposite via spark plasma sintering of nanostructured Ti1-xAlxN-AlN powders. Flash spark plasma sintering of ultrafine yttria-stabilized zirconia ceramics. Hot-spots generation, exaggerated grain growth and mechanical performance of silicon carbide bulks consolidated by flash-SPS. Nanoexplosion synthesis of multimetal oxide ceramic nanopowders. Nano-engineering of zirconia-noble metals composites. Nanoreactor engineering and SPS densification of multimetal oxide ceramic nanopowders. Synthesis and magnetic properties of self-assembled magnetite-chitosan nanostructures. Tough yttria-stabilized zirconia nanoceramic by low-temperature SPS. High-toughness tetragonal zirconia and zirconia/alumina nano-ceramics. Tough yttria-stabilized zirconia nanoceramic by low-temperature presureless consolidation. Nanoblast synthesis and SPS of nanostructured oxides for SOFC.

出版物2004年以降のNIMS所属における研究成果や出版物を表示しています。

会議録
特許

所属学会

The Ceramic Society of Japan

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第二期開発予定
第二期開発予定

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