Research activity information

• Sintering and microstructure evolution in highly porous yttrium iron oxide ceramics

  Dmytro Demirskyi, Minoru Takeda

  Abstract The evolution of the microstructure in highly porous compacts was analyzed using scanning electron microscopy on yttrium iron oxide samples exhibiting densities of less than 30% of theoretical density. During grain growth in highly porous compacts, the grains initially form a mesh chain structure, followed by either elongation or the formation of ring‐like structures, and finally assembly into hollow or coarser spheres. The latter process may involve the formation of fine necks growing through the ring structure, acting as the core of a coarser sphere. Thus, YFeO₃ porous materials have macroscopic and microscopic pores, and the total porosity level as well as porous cluster sizes inside granules can be controlled by adjusting temperature or dwell time.

  Wiley, Aug. 2025, Journal of the American Ceramic Society, 108(12) (12)

  Scientific journal


• Iron hydroxide ceramic for ortho-to para-hydrogen conversion: Synthesis, phase evolution, and long-term storage

  Dmytro Demirskyi, Minoru Takeda

  Elsevier BV, Aug. 2025, International Journal of Hydrogen Energy, 159, 150347 - 150347

  Scientific journal


• High‐temperature deformation and consolidation of polycrystalline α‐SiC by spark plasma sintering

  Dmytro Demirskyi, Hossein Sepehri‐Amin, Oleg O. Vasylkiv

  Mar. 2025, International Journal of Applied Ceramic Technology

  Scientific journal


• High‐temperature strength behavior of tantalum diboride to 2000°C

  Oleg Vasylkiv, Dmytro Demirskyi

  Nov. 2023, Journal of the American Ceramic Society

  Scientific journal


• Preparation of high‐strength (Ta,W)C solid‐solutions by spark plasma sintering

  Dmytro Demirskyi, Kyosuke Yoshimi, Tohru S. Suzuki, Oleg O. Vasylkiv

  Abstract (Ta,W)C bulks were prepared by spark plasma sintering. Densification kinetics and solid‐solution formation kinetics were performed on the powder mixtures using TaC and W powders. The as‐received tungsten powder had a spherical shape and rather coarse size. By using the crushed and as‐received powder, it can be suggested that sintering at 2000°C limits the reaction volume to 3–6 μm and hence allows forming a complete solid‐solution using finer powders. The lattice parameter, hardness, toughness, and strength were investigated as a function of the TaC content. The flexural strength of the (Ta,W)C ceramic bulks was investigated up to 2000°C and it was found that the maximum strength was for the 60 mol.% TaC composition. Strength as a function of the temperature tended to increase up to 1200°C followed by a gradual decrease to 2000°C. When the TaC was reinformed by coarse W spheres, the flexural strength monotonically decreased from 570 MPa at room temperature to 220 MPa at 2000°C.

  Wiley, May 2023, International Journal of Applied Ceramic Technology, 20(5) (5), 2747 - 2759

  Scientific journal


• Reactive consolidation of tough, deformation resistant tantalum monoboride

  D. Demirskyi, K. Yoshimi, T.S. Suzuki, O. Vasylkiv

  Elsevier BV, May 2023, Scripta Materialia, 229, 115383 - 115383

  Scientific journal


• High-strength, medium entropy Zr-Ta-Nb diboride ceramics

  D. Demirskyi, T. Nishimura, K. Yoshimi, O. Vasylkiv

  Elsevier BV, Mar. 2023, Scripta Materialia, 225, 115170 - 115170

  Scientific journal


• High‐temperature reactive synthesis of the Zr–Ta multiboride with a supercomposite structure

  Dmytro Demirskyi, Tohru S. Suzuki, Kyosuke Yoshimi, Oleg Vasylkiv

  Wiley, Nov. 2022, Journal of the American Ceramic Society, 105(11) (11), 6989 - 7002

  Scientific journal


• Reactive consolidation and high-temperature strength of HfB2–SiB6

  D. Demirskyi, T. Nishimura, T. S. Suzuki, K. Yoshimi, O. Vasylkiv

  Sep. 2022, Journal of the European Ceramic Society, 42(12) (12), 4783 - 4792

  Scientific journal


• Consolidation and high‐temperature properties of ceramics in the TaC–NbC system

  Dmytro Demirskyi, T. Nishimura, T. S. Suzuki, K. Yoshimi, Oleg Vasylkiv

  Wiley, Jul. 2022, Journal of the American Ceramic Society, 105(12) (12), 7567 - 7581

  Scientific journal


• Consolidation and high-temperature strength of monolithic lanthanum hexaboride

  Dmytro Demirskyi, Tohru S. Suzuki, Kyosuke Yoshimi, Oleg O. Vasylkiv

  Jun. 2022, Journal of the American Ceramic Society, 105(6) (6), 4277 - 4290

  Scientific journal


• Ultra-high temperature flexure and strain driven amorphization in polycrystalline boron carbide bulks

  D. Demirskyi, H. Sepehri-Amin, T. S. Suzuki, K. Yoshimi, O. Vasylkiv

  Mar. 2022, Scripta Materialia, 210

  Scientific journal


• Fracture peculiarities and high-temperature strength of bulk polycrystalline boron

  D. Demirskyi, P. Badica, A. Kuncser, O. Vasylkiv

  Mar. 2022, Materialia, 21

  Scientific journal


• Deformation-resistant Ta0.2Hf0.8C solid-solution ceramic with superior flexural strength at 2000°C

  Dmytro Demirskyi, Hanna Borodianska, Toshiyuki Nishimura, Tohru S. Suzuki, Kyosuke Yoshimi, Oleg Vasylkiv

  Jan. 2022, Journal of the American Ceramic Society, 105(1) (1), 512 - 524

  Scientific journal


• High-temperature deformation in bulk polycrystalline hafnium carbide consolidated using spark plasma sintering

  D. Demirskyi, O. Vasylkiv, K. Yoshimi

  Dec. 2021, Journal of the European Ceramic Society, 41(15) (15), 7442 - 7449

  Scientific journal


• Allotropic strengthening and in situ phase transformations during ultra-high-temperature flexure of bulk tantalum nitride

  D. Demirskyi, O. Vasylkiv, K. Yoshimi

  Oct. 2021, Materials Science and Engineering A, 826

  Scientific journal


• Synthesis of medium-entropy (Zr1/3Hf1/3Ta1/3)B2 using the spark plasma consolidation of diboride powders

  Dmytro DEMIRSKYI, Tohru S. SUZUKI, Kyosuke YOSHIMI, Oleg VASYLKIV

  Nov. 2020, Journal of the Ceramic Society of Japan, 128(11) (11), 977 - 980

  Scientific journal


• Synthesis and high-temperature properties of medium-entropy (Ti,Ta,Zr,Nb)C using the spark plasma consolidation of carbide powders

  D. Demirskyi, T.S. Suzuki, K. Yoshimi, O. Vasylkiv

  Elsevier BV, Jul. 2020, Open Ceramics, 2, 100015 - 100015

  [Refereed]

  Scientific journal


• High-temperature strength of boron carbide with Pt grain-boundary framework in situ synthesized during spark plasma sintering

  O. Vasylkiv, D. Demirskyi, H. Borodianska, A. Kuncser, P. Badica

  Elsevier BV, May 2020, Ceramics International, 46(7) (7), 9136 - 9144

  [Refereed]

  Scientific journal


• High-temperature toughening in ternary medium-entropy (Ta1/3Ti1/3Zr1/3)C carbide consolidated using spark-plasma sintering

  D. Demirskyi, T. Nishimura, T. S. Suzuki, Y. Sakka, O. Vasylkiv, K. Yoshimi

  2020, Journal of Asian Ceramic Societies, 8(4) (4), 1262 - 1270

  Scientific journal


• Bulks of Al-B-C obtained by reactively spark plasma sintering and impact properties by Split Hopkinson Pressure Bar

  O. Vasylkiv, H. Borodianska, D. Demirskyi, P. Li, T. S. Suzuki, M. A. Grigoroscuta, I. Pasuk, A. Kuncser, P. Badica

  Springer Science and Business Media LLC, Dec. 2019, Scientific Reports, 9(1) (1)

  [Refereed]

  Scientific journal


• Fracture and property relationships in the double diboride ceramic composites by spark plasma sintering of TiB 2 and NbB 2

  Dmytro Demirskyi, Ievgen Solodkyi, Toshiyuki Nishimura, Oleg O. Vasylkiv

  Wiley, Jul. 2019, Journal of the American Ceramic Society, 102(7) (7), 4259 - 4271

  [Refereed]

  Scientific journal


• Microstructure and flexural strength of hafnium diboride via flash and conventional spark plasma sintering

  D. Demirskyi, T.S. Suzuki, S. Grasso, O. Vasylkiv

  Elsevier BV, Apr. 2019, Journal of the European Ceramic Society, 39(4) (4), 898 - 906

  [Refereed]

  Scientific journal


• High-temperature flexural strength performance of ternary high-entropy carbide consolidated via spark plasma sintering of TaC, ZrC and NbC

  D. Demirskyi, H. Borodianska, T.S. Suzuki, Y. Sakka, K. Yoshimi, O. Vasylkiv

  Apr. 2019, Scripta Materialia, 164, 12 - 16, English

  [Refereed]

  Scientific journal


• High-temperature strength and plastic deformation behavior of niobium diboride consolidated by spark plasma sintering

  Dmytro Demirskyi, Ievgen Solodkyi, Toshiyuki Nishimura, Yoshio Sakka, Oleg Vasylkiv

  Nov. 2017, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 100(11) (11), 5295 - 5305, English

  [Refereed]

  Scientific journal


• Flexural strength behavior of a ZrB2-TaB2 composite consolidated by non-reactive spark plasma sintering at 2300 degrees C

  Dmytro Demirskyi, Oleg Vasylkiv

  Aug. 2017, INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, 66, 31 - 35, English

  [Refereed]

  Scientific journal


• Spark plasma sintering and high-temperature strength of B6O-TaB2 ceramics

  Dmytro Demirskyi, Oleg Vasylkiv

  Jul. 2017, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 37(8) (8), 3009 - 3014, English

  [Refereed]

  Scientific journal


• Analysis of the high-temperature flexural strength behavior of B4C-TaB2 eutectic composites produced by in situ spark plasma sintering

  Dmytro Demirskyi, Oleg Vasylkiv

  Jun. 2017, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 697, 71 - 78, English

  [Refereed]

  Scientific journal


• Ultra-high elevated temperature strength of TiB2-based ceramics consolidated by spark plasma sintering

  Dmytro Dernirskyi, Hanna Borodianska, Yoshio Sakka, Oleg Vasylkiv

  Jan. 2017, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 37(1) (1), 393 - 397, English

  [Refereed]

  Scientific journal


• Hot-spots generation, exaggerated grain growth and mechanical performance of silicon carbide bulks consolidated by flash spark plasma sintering

  Dmytro Demirskyi, Oleg Vasylkiv

  Jan. 2017, JOURNAL OF ALLOYS AND COMPOUNDS, 691, 466 - 473, English

  [Refereed]

  Scientific journal


• Mechanical properties of SiC-NbB2 eutectic composites by in situ spark plasma sintering

  Dmytro Demirskyi, Oleg Vasylkiv

  Dec. 2016, CERAMICS INTERNATIONAL, 42(16) (16), 19372 - 19385, English

  [Refereed]

  Scientific journal


• Consolidation and grain growth of tantalum diboride during spark plasma sintering

  Dmytro Demirskyi, Oleg Vasylkiv

  Nov. 2016, CERAMICS INTERNATIONAL, 42(14) (14), 16396 - 16400, English

  [Refereed]

  Scientific journal


• Microstructure and mechanical properties of boron suboxide ceramics prepared by pressureless microwave sintering

  Dmytro Demirskyi, Oleg Vasylkiv

  Sep. 2016, CERAMICS INTERNATIONAL, 42(12) (12), 14282 - 14286, English

  [Refereed]

  Scientific journal


• High-Temperature Strength of Boron Suboxide Ceramic Consolidated by Spark Plasma Sintering

  Dmytro Demirskyi, Ievgen Solodkyi, Yoshio Sakka, Oleg Vasylkiv

  Aug. 2016, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 99(8) (8), 2769 - 2777, English

  [Refereed]

  Scientific journal


• Flash spark plasma sintering of ultrafine yttria-stabilized zirconia ceramics

  Oleg Vasylkiv, Hanna Borodianska, Yoshio Sakka, Dmytro Demirskyi

  Aug. 2016, SCRIPTA MATERIALIA, 121, 32 - 36, English

  [Refereed]

  Scientific journal


• High-Strength B4C-TaB2 Eutectic Composites Obtained via In Situ by Spark Plasma Sintering

  Dmytro Demirskyi, Yoshio Sakka, Oleg Vasylkiv

  Jul. 2016, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 99(7) (7), 2436 - 2441, English

  [Refereed]

  Scientific journal


• Room and high temperature flexural failure of spark plasma sintered boron carbide

  O. Vasylkiv, D. Demirskyi, P. Badica, T. Nishimura, A. I. Y. Tok, Y. Sakka, H. Borodianska

  May 2016, CERAMICS INTERNATIONAL, 42(6) (6), 7001 - 7013, English

  [Refereed]

  Scientific journal


• High temperature flexural strength in monolithic boron carbide ceramic obtained from two different raw powders by spark plasma sintering

  Oleg Vasylkiv, Dmytro Demirskyi, Hanna Borodianska, Yoshio Sakka, Petre Badica

  May 2016, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 124(5) (5), 587 - 592, English

  [Refereed]

  Scientific journal


• Hardness and toughness control of brittle boron suboxide ceramics by consolidation of star-shaped particles by spark plasma sintering

  Ievgen Solodkyi, Dmytro Demirskyi, Yoshio Sakka, Oleg Vasylkiv

  Feb. 2016, CERAMICS INTERNATIONAL, 42(2) (2), 3525 - 3530, English

  [Refereed]

  Scientific journal


• High-strength TiB2-TaC ceramic composites prepared using reactive spark plasma consolidation

  Dmytro Demirskyi, Toshiyuki Nishimura, Yoshio Sakka, Oleg Vasylkiv

  Jan. 2016, CERAMICS INTERNATIONAL, 42(1) (1), 1298 - 1306, English

  [Refereed]

  Scientific journal


• Synthesis of Multilayered Star-Shaped B6O Particles Using the Seed-Mediated Growth Method

  Ievgen Solodkyi, Dmytro Demirskyi, Yoshio Sakka, Oleg Vasylkiv

  Dec. 2015, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 98(12) (12), 3635 - 3638, English

  [Refereed]

  Scientific journal


• High-temperature reactive spark plasma consolidation of TiB2-NbC ceramic composites

  Dmytro Demirskyi, Yoshio Sakka, Oleg Vasylkiv

  Nov. 2015, CERAMICS INTERNATIONAL, 41(9) (9), 10828 - 10834, English

  [Refereed]

  Scientific journal


• Consolidation of B4C-VB2 eutectic ceramics by spark plasma sintering

  Dmytro Demirskyi, Yoshio Sakka, Oleg Vasylkiv

  Nov. 2015, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 123(1443) (1443), 1051 - 1054, English

  [Refereed]

  Scientific journal


• High-temperature reaction consolidation of TaC-TiB2 ceramic composites by spark-plasma sintering

  D. Demirskyi, Y. Sakka

  Jan. 2015, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 35(1) (1), 405 - 410, English

  [Refereed]

  Scientific journal


• Fabrication, microstructure and properties of in situ synthesized B4C-NbB2 eutectic composites by spark plasma sintering

  Dmytro Demirskyi, Yoshio Sakka

  Jan. 2015, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 123(1433) (1433), 33 - 37, English

  [Refereed]

  Scientific journal


• Consolidation of B4C-TaB2 eutectic composites by spark plasma sintering

  Demirskyi, Dmytro, Sakka, Yoshio, Vasylkiv, Oleg

  2015, Journal of Asian Ceramic Societies, 3(4) (4), 369 - 372

  [Refereed]

  Scientific journal


• In Situ Fabrication of B4C-NbB2 Eutectic Composites by Spark-Plasma Sintering

  Dmytro Demirskyi, Yoshio Sakka

  Aug. 2014, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 97(8) (8), 2376 - 2378, English

  [Refereed]

  Scientific journal


• Toughness control of boron carbide obtained by spark plasma sintering in nitrogen atmosphere

  Petre Badica, Hanna Borodianska, Shumao Xie, Ting Zhao, Dmytro Demirskyi, Peifeng Li, Alfred I. Y. Tok, Yoshio Sakka, Oleg Vasylkiv

  Mar. 2014, CERAMICS INTERNATIONAL, 40(2) (2), 3053 - 3061, English

  [Refereed]

  Scientific journal


• Tough ceramics by microwave sintering of nanocrystalline titanium diboride ceramics

  D. Demirskyi, D. Agrawal, A. Raguya

  Jan. 2014, CERAMICS INTERNATIONAL, 40(1) (1), 1303 - 1310, English

  [Refereed]

  Scientific journal


• Densification and grain growth during microwave sintering of titanium diboride

  D. Demirskyi, J. Cheng, D. Agrawal, A. Ragulya

  Oct. 2013, SCRIPTA MATERIALIA, 69(8) (8), 610 - 613, English

  [Refereed]

  Scientific journal


• Comparisons of grain size-density trajectory during microwave and conventional sintering of titanium nitride

  D. Demirskyi, D. Agrawal, A. Ragulya

  2013, Journal of Alloys and Compounds, 581, 498 - 501, English

  [Refereed]

  Scientific journal


• Grain boundary diffusion driven spark plasma sintering of nanocrystalline zirconia

  Hanna Borodianska, Dmytro Demirskyi, Yoshio Sakka, Petre Badica, Oleg Vasylkiv

  Jul. 2012, CERAMICS INTERNATIONAL, 38(5) (5), 4385 - 4389, English

  [Refereed]

  Scientific journal


• Densification Kinetics of Nanocrystalline Zirconia Powder Using Microwave and Spark Plasma Sintering-A Comparative Study

  Oleg Vasylkiv, Dmytro Demirskyi, Yoshio Sakka, Andrey Ragulya, Hanna Borodianska

  Jun. 2012, JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 12(6) (6), 4577 - 4582, English

  [Refereed]

  Scientific journal


• Peculiarities of the neck growth process during initial stage of spark-plasma, microwave and conventional sintering of WC spheres

  Dmytro Demirskyi, Hanna Borodianska, Dinesh Agrawal, Andrey Ragulya, Yoshio Sakka, Oleg Vasylkiv

  May 2012, JOURNAL OF ALLOYS AND COMPOUNDS, 523, 1 - 10, English

  [Refereed]

  Scientific journal


• Low-temperature microwave sintering of TiN-SiC nanocomposites

  Dmytro Demirskyi, Andrey Ragulya

  Apr. 2012, JOURNAL OF MATERIALS SCIENCE, 47(8) (8), 3741 - 3745, English

  [Refereed]

  Scientific journal


• A scaling law study of the initial stage of microwave sintering of iron spheres

  D. Demirskyi, D. Agrawal, A. Ragulya

  Mar. 2012, SCRIPTA MATERIALIA, 66(6) (6), 323 - 326, English

  [Refereed]

  Scientific journal


• Microstructure evolution during field-assisted sintering of zirconia spheres

  D. Demirskyi, H. Borodianska, S. Grasso, Y. Sakka, O. Vasylkiv

  Oct. 2011, SCRIPTA MATERIALIA, 65(8) (8), 683 - 686, English

  [Refereed]

  Scientific journal


• Initial stage sintering of binderless tungsten carbide powder under microwave radiation

  Dmytro Demirskyi, Andrey Ragulya, Dinesh Agrawal

  Mar. 2011, CERAMICS INTERNATIONAL, 37(2) (2), 505 - 512, English

  [Refereed]

  Scientific journal


• Neck growth kinetics during microwave sintering of nickel powder

  D. Demirskyi, D. Agrawal, A. Ragulya

  Feb. 2011, JOURNAL OF ALLOYS AND COMPOUNDS, 509(5) (5), 1790 - 1795, English

  [Refereed]

  Scientific journal


• Densification kinetics of powdered copper under single-mode and multimode microwave sintering

  D. Demirskyi, D. Agrawal, A. Ragulya

  Jul. 2010, MATERIALS LETTERS, 64(13) (13), 1433 - 1436, English

  [Refereed]

  Scientific journal


• INITIAL KINETICS OF MICROWAVE SINTERING OF COPPER

  D. N. Demirskii, A. V. Ragulya

  Jul. 2010, POWDER METALLURGY AND METAL CERAMICS, 49(3-4) (3-4), 147 - 152, English

  [Refereed]

  Scientific journal


• Neck growth kinetics during microwave sintering of copper

  D. Demirskyi, D. Agrawal, A. Ragulya

  Apr. 2010, SCRIPTA MATERIALIA, 62(8) (8), 552 - 555, English

  [Refereed]

  Scientific journal


• Neck formation between copper spherical particles under single-mode and multimode microwave sintering

  D. Demirskyi, D. Agrawal, A. Ragulya

  Mar. 2010, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 527(7-8) (7-8), 2142 - 2145, English

  [Refereed]

  Scientific journal

• 電磁界印加焼結技術の基礎過程とその応用展開

  目 義雄, DEMIRSKYI Dmytro

  日本学術振興会, 科学研究費助成事業, 特別研究員奨励費, 独立行政法人物質・材料研究機構, 01 Apr. 2013 - 31 Mar. 2015

  パルス通電加圧焼結（通称Spark Plasama Sintering (SPS)と称される）は、飛躍的な材料特性の改善とエネルギー効率の大幅な削減が可能な最新粉体加工技術として、近年急速に発展している技術である。SPSはパンチを通して試料が直接通電、加熱される。大電流をパルス的に印加するため短時間焼結が可能であり、ナノ構造材料や特殊複合材料の作製に適しているが、高温材料への適用、反応焼結による高温材料の作製とその評価に関する研究は限られている。本研究では、SPSおよびマイクロ波焼結により、１）B4C－MeB2（Me:Nb, Ta, V)系の共晶組成コンポジットの作製と特性評価、２）反応焼結によるTiB2系高温セラミックスの作製、を行った。 1) B4C-MeB2（Me:Nb, Ta, V)系に関し、温度を2000-2150 °C (共晶温度より100℃低い温度）、加圧力を 5, 10 and 20 MPa と変化させ、プロセスパラメータと得られる組織、特性の関係を検討した。SPSの計測温度はシミュレーションにより実際の温度より低いこと、焼結収縮が急激に起こる温度は圧力が高くなると低下することを実証した。NbB2のロッド径と硬度の関係、NbB2ロッド間距離と硬度、破壊靭性の関係を見出し、プロセスパラメータと組織、特性に関する指針を示すことができた。 ２）TiB2-TaCおよびTiB2-NbC系コンポジットをSPS反応焼結により作製した。TiとNbの固溶度と微構造の関係、TiB2-TaCおよびTiB2-NbC系の組成と微構造、硬度の関係を明らかにし、反応焼結による高性能材料創製のための指針を得た。 これらの成果は、J. Am. Ceram. Soc., J. Ceram. Soc. Jpn., J. Europ. Ceram. Soc.に掲載され、現在２報を投稿中である。