المؤلفون: Šebek M., Falat L., Kováč F., Petryshynets I., Horňak P., Girman V.

المصدر: Archives of Metallurgy and Materials, Vol 62, Iss 3, Pp 1721-1726 (2017)

مصطلحات موضوعية: Hot work tool steel, laser hardening, microstructure, hardness, wear resistance, Mining engineering. Metallurgy, TN1-997, Materials of engineering and construction. Mechanics of materials, TA401-492

الوصف: The present study deals with the effects of laser surface treatment on microstructure evolution and wear resistance of AISI H11 hot work tool steel in quenched and tempered condition. The most upper laser-affected zone is characterized by re-melted microstructure consisting of dendrite cells with fresh non-tempered martensite, retained austenite and inter-dendritic carbidic network. The subsolidus microstructure just beneath the re-melted zone represents the most laser surface hardened zone consisting of fresh non-tempered martensite with fine and coarse carbides as a result of overheating the original QT substrate microstructure. The highest microhardness values in the range from 775 to 857 HV were measured for the LSH microstructure and the most softened microstructure exhibited the minimum hardness of 530 HV. The laser treated samples showed the improvement of their surface wear resistance by 35%.

وصف الملف: electronic resource

العلاقة: http://www.degruyter.com/view/j/amm.2017.62.issue-3/amm-2017-0262/amm-2017-0262.xml?format=INTTest; https://doaj.org/toc/2300-1909Test

الوصول الحر: https://doaj.org/article/576d64d6df654f309b49819ede918a11Test

المؤلفون: Bera, C., Streckova, M., Orinakova, R., Guboova, A., Bystron, T., Girman, V., Kromka, F., Podobova, M., Bouzek, K.

المساهمون: Agentúra Ministerstva Školstva, Vedy, Výskumu a Športu SR, Slovak Research and Development Agency, European Regional Development Fund, Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, Slovenská Akadémia Vied, Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky, Society for Anthropological Sciences

المصدر: International Journal of Hydrogen Energy ; volume 60, page 118-132 ; ISSN 0360-3199

مصطلحات موضوعية: Energy Engineering and Power Technology, Condensed Matter Physics, Fuel Technology, Renewable Energy, Sustainability and the Environment

الإتاحة: https://doi.org/10.1016/j.ijhydene.2024.02.195Test
https://api.elsevier.com/content/article/PII:S0360319924006177?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0360319924006177?httpAccept=text/plainTest

المؤلفون: Khmara, I., Antal, I., Jurikova, A., Kubovcikova, M., Zavisova, V., Girman, V., Koneracka, M.

المساهمون: European Regional Development Fund, Agentúra na Podporu Výskumu a Vývoja

المصدر: Journal of Magnetism and Magnetic Materials ; volume 591, page 171748 ; ISSN 0304-8853

مصطلحات موضوعية: Condensed Matter Physics, Electronic, Optical and Magnetic Materials

الإتاحة: https://doi.org/10.1016/j.jmmm.2024.171748Test
https://api.elsevier.com/content/article/PII:S0304885324000386?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0304885324000386?httpAccept=text/plainTest

المؤلفون: Najafzadehkhoee, A., Talimian, A., Girman, V., Sedlák, R., Hvizdoš, P., Maca, K., Galusek, D.

المساهمون: Horizon 2020 Marie Skłodowska-Curie Actions, Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky, Slovak Research and Development Agency, Horizon 2020

المصدر: Journal of the European Ceramic Society ; volume 44, issue 1, page 383-392 ; ISSN 0955-2219

مصطلحات موضوعية: Materials Chemistry, Ceramics and Composites

الإتاحة: https://doi.org/10.1016/j.jeurceramsoc.2023.08.055Test
https://api.elsevier.com/content/article/PII:S0955221923006817?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0955221923006817?httpAccept=text/plainTest

المؤلفون: Casalegno V., Perero S., Girman V., Sedlak R., Scarpellini A., Dorow-Gerspach D., Heuer S., Ferraris M.

المساهمون: Casalegno, V., Perero, S., Girman, V., Sedlak, R., Scarpellini, A., Dorow-Gerspach, D., Heuer, S., Ferraris, M.

مصطلحات موضوعية: W/steel joints, sputtering, joining, nuclear

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:001009154300001; volume:35; firstpage:1; lastpage:11; numberofpages:11; journal:NUCLEAR MATERIALS AND ENERGY; https://hdl.handle.net/11583/2978092Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85150779241; https://www.sciencedirect.com/science/article/pii/S2352179123000601?via=ihubTest

الإتاحة: https://doi.org/10.1016/j.nme.2023.101421Test
https://hdl.handle.net/11583/2978092Test
https://www.sciencedirect.com/science/article/pii/S2352179123000601?via=ihubTest

المؤلفون: Zeleňáková, A., Hrubovčák, P., Berkutova, A., Šofranko, O., Kučerka, N., Ivankov, O., Kuklin, A., Girman, V., Zeleňák, V.

المساهمون: Agentúra na Podporu Výskumu a Vývoja, Ministery of Education Slovakia, Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, Joint Institute for Nuclear Research

المصدر: Scientific Reports ; volume 12, issue 1 ; ISSN 2045-2322

مصطلحات موضوعية: Multidisciplinary

الوصف: The series of advanced nanocomposites consisting of Gd 2 O 3 nanoparticles (NPs) embedded into periodic porous SiO 2 matrix have been investigated with respect to their structural and magnetocaloric properties. By means of small angle neutron scattering and transmission electron microscopy, regular nanopores organized in the cubic or hexagonal superlattice have been documented. The pores are occupied by the NPs of progressive concentration within the nanocomposite series. All of the examined systems have exhibited extraordinarily high values of magnetic entropy change (up to 70 J kg −1 K −1 ) at low temperatures with the absence of thermal hysteresis, indicating their perspective utilization in cryogenic refrigeration. Profound analysis of magnetic entropy change data via scaling laws has been applied to the nanocomposite materials for the very first time. With the aid of scaling analysis, conclusions on magnetic properties and phase transition type have been made, even for the conditions unavailable in the laboratory.

الإتاحة: https://doi.org/10.1038/s41598-022-06132-8Test
https://www.nature.com/articles/s41598-022-06132-8.pdfTest
https://www.nature.com/articles/s41598-022-06132-8Test

المؤلفون: Lofaj, F., Kabátová, M., Klich, M., Medveď, D., Girman, V.

المصدر: Cerâmica. January 2019 65(1)

مصطلحات موضوعية: W-C:H coatings, DC magnetron sputtering (DCMS), high power impulse magnetron sputtering (HiPIMS), high target utilization sputtering (HiTUS), hardness, coefficient of friction

الوصف: The evolution of structure, mechanical properties and friction behavior of DC magnetron sputtered (DCMS), high power impulse magnetron sputtered (HiPIMS) and high target utilization sputtered (HiTUS) W-C:H coatings was investigated as a function of the addition of acetylene and hydrogen into Ar atmosphere. The gradual addition of reactive gases caused a transition from PVD toward hybrid PVD-PECVD and even PECVD dominant processes. The coating structure evolved from nanocrystalline toward nanocomposite and amorphous structure with the increase of acetylene addition. Deposition rates in all techniques increased linearly with the increase of acetylene flow until certain saturation limit due to the limited energy available for acetylene fragmentation during hybrid PVD-PECVD deposition. Hardness and coefficient of friction in DCMS and HiTUS W-C:H coatings deposited in this regime followed standard congruent tendencies whereas PECVD dominated deposition process produced coatings with different dependencies. In contrary, HiPIMS W-C:H coatings showed low sensitivity to the influence of acetylene and hydrogen additions. Lower coefficients of friction (<0.1) and moderate hardness (around 20 GPa) of HiPIMS W-C:H coatings over a wide range of acetylene additions seem to be a principal advantage of HiPIMS compared to DCMS and HiTUS techniques in this class of coatings.

وصف الملف: text/html

الوصول الحر: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132019000500058Test

المؤلفون: Porodko, O., Fabián, M., Kolev, H., Lisnichuk, M., Zukalová, M., Vinarčíková, M., Girman, V., Da Silva, K. L., Šepelák, V.

المصدر: Zeitschrift fur Physikalische Chemie, 236 (6-8), 713–726 ; ISSN: 0942-9352, 0044-3336, 0372-8501, 0372-9656, 0372-9664, 2196-7156

مصطلحات موضوعية: ddc:600, Technology, info:eu-repo/classification/ddc/600

الوصف: For the first time, a spinel-type high entropy oxide (Zn$_{0.25}$Cu$_{0.25}$Mg$_{0.25}$Co$_{0.25}$)Al$_{2}$O$_{4}$ as well as its derivative lithiated high entropy oxyfluoride Li$_{0.5}$(Zn$_{0.25}$Cu$_{0.25}$Mg$_{0.25}$Co$_{0.25}$)$_{0.5}$Al$_{2}$O$_{3.5}$F$_{0.5}$ and oxychloride Li$_{0.5}$(Zn$_{0.25}$Cu$_{0.25}$Mg$_{0.25}$Co$_{0.25}$)$_{0.5}$Al$_{2}$O$_{3.5}$Cl$_{0.5}$ are prepared in the nanostructured state via high-energy co-milling of the simple oxide precursors and the halides (LiF or LiCl) as sources of lithium, fluorine and chlorine. Their nanostructure is investigated by XRD, HR-TEM, EDX and XPS spectroscopy. It is revealed that incorporation of lithium into the structure of spinel oxide together with the anionic substitution has significant effect on its short-range order, size and morphology of crystallites as well as on its oxidation/reduction processes. The charge capacity of the as-prepared nanomaterials tested by cyclic voltammetry is found to be rather poor despite lithiation of the samples in comparison to previously reported spinel-type high entropy oxides. Nevertheless, the present work offers the alternative one-step mechanochemical route to novel classes of high entropy oxides as well as to lithiated oxyfluorides and oxychlorides with the possibility to vary their cationic and anionic elemental composition.

وصف الملف: application/pdf

العلاقة: info:eu-repo/semantics/altIdentifier/issn/0942-9352; info:eu-repo/semantics/altIdentifier/issn/0044-3336; info:eu-repo/semantics/altIdentifier/issn/0372-8501; info:eu-repo/semantics/altIdentifier/issn/0372-9656; info:eu-repo/semantics/altIdentifier/issn/0372-9664; info:eu-repo/semantics/altIdentifier/issn/2196-7156; https://publikationen.bibliothek.kit.edu/1000139367Test; https://publikationen.bibliothek.kit.edu/1000139367/139670566Test; https://doi.org/10.5445/IR/1000139367Test

الإتاحة: https://doi.org/10.5445/IR/1000139367Test
https://doi.org/10.1515/zpch-2021-3106Test
https://publikationen.bibliothek.kit.edu/1000139367Test
https://publikationen.bibliothek.kit.edu/1000139367/139670566Test

المؤلفون: Stelmakova, M., Streckova, M., Orinakova, R., Guboova, A., Balaz, M., Girman, V., Mudra, E., Bera, C., Batkova, M.

المساهمون: Agentúra Ministerstva Školstva, Vedy, Výskumu a Športu SR, Agentúra na Podporu Výskumu a Vývoja

المصدر: Chemical Papers ; volume 76, issue 2, page 855-867 ; ISSN 0366-6352 2585-7290

مصطلحات موضوعية: Materials Chemistry, Industrial and Manufacturing Engineering, General Chemical Engineering, Biochemistry, General Chemistry

الإتاحة: https://doi.org/10.1007/s11696-021-01897-0Test

المؤلفون: Skurikhina, O., Senna, M., Fabián, M., Witte, R., Tarasenko, R., Tkáč, V., Orendáč, M., Kaňuchová, M., Girman, V., Harničárová, M., Valíček, J., Šepelák, V., Tóthová, E.

المصدر: Ceramics international, 46 (10; Part A), 14894-14901 ; ISSN: 0272-8842, 1873-3956

مصطلحات موضوعية: ddc:600, Technology, info:eu-repo/classification/ddc/600

الوصف: Lithium-iron methasilicate (LiFeSi$_{2}$O$_{6}$, LFS), a member of clinopyroxene family, is an attractive compound for its multiferroic properties and applicability in energy-related devices. Conventional preparative method requires heating at elevated temperatures for long periods of time, with inevitable severe grain growth. We demonstrate that α-FeO(OH) (goethite) is superior as an iron source toward phase pure LFS over conventional hematite, α-Fe$_{2}$O$_{3}$. The exact phase purity, i.e., no trace of iron containing reactant, is confirmed in the goethite-derived LFS by 57Fe Mössbauer spectroscopy. The grain growth of LFS during heating is suppressed to keep its crystallite size of 120 nm. Higher reactivity of goethite in comparison with hematite is mainly attributed to the dehydration of goethite, which in our case was accelerated by Li$_{2}$O. Related reaction mechanisms with the possible product pre-nucleation during mechanical activation are also mentioned. The magnetic properties of goethite-derived LFS are equivalent to those prepared via a laborious solid-state route. Thus, the presented preparative method offers a more sustainable route than conventional processing, and thus enables practical application of LFS.

وصف الملف: application/pdf

العلاقة: info:eu-repo/semantics/altIdentifier/wos/000533511200064; info:eu-repo/semantics/altIdentifier/issn/0272-8842; info:eu-repo/semantics/altIdentifier/issn/1873-3956; https://publikationen.bibliothek.kit.edu/1000118236Test; https://publikationen.bibliothek.kit.edu/1000118236/142739025Test; https://doi.org/10.5445/IR/1000118236Test

الإتاحة: https://doi.org/10.5445/IR/1000118236Test
https://doi.org/10.1016/j.ceramint.2020.03.016Test
https://publikationen.bibliothek.kit.edu/1000118236Test
https://publikationen.bibliothek.kit.edu/1000118236/142739025Test