Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides
This paper is devoted to the celebration of 75 years’ jubilee of Professor Zulkhair Mansurov. One of the authors (Roberto Orrù) would like to acknowledge Zulkhair Mansurov for his vigorous effort given for the development and diffusion of the Eurasian Chemico-Technological Journal. The fabr...
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| Format: | Article |
| Language: | English |
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al-Farabi Kazakh National University
2021-11-01
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| Series: | Eurasian Chemico-Technological Journal |
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| Online Access: | https://ect-journal.kz/index.php/ectj/article/view/1104 |
| _version_ | 1819161691125972992 |
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| author | S. Barbarossa M. Murgia R. Orrù G. Cao |
| author_facet | S. Barbarossa M. Murgia R. Orrù G. Cao |
| author_sort | S. Barbarossa |
| collection | DOAJ |
| description |
This paper is devoted to the celebration of 75 years’ jubilee of Professor Zulkhair Mansurov. One of the authors (Roberto Orrù) would like to acknowledge Zulkhair Mansurov for his vigorous effort given for the development and diffusion of the Eurasian Chemico-Technological Journal.
The fabrication by Spark Plasma Sintering (SPS) of bulk high entropy ceramics from powders obtained by Self-propagating High temperature Synthesis (SHS) is addressed in this work. The effect produced by the introduction of 1 wt.% of graphite to the powders before SPS is investigated under different temperature conditions. The final density and composition of sintered (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 and (Hf0.2Mo0.2Zr0.2Ti0.2Nb0.2)B2 ceramics are found to be negatively affected by the presence of oxide impurities in the powders. While product composition can be progressively improved when the temperature is increased from 1800 to 1950 °C, residual porosities remain relatively high if using additive-free powders. In contrast, the introduction of 1 wt.%C markedly allows for oxides elimination by carbothermal reduction mechanism. Products consolidation is correspondingly enhanced so that relative densities of about 97% are attained. Other than the latter effect, surface oxides removal also makes powders more reactive, thus the synthesis of single-phase products is promoted. In particular, fully homogeneous (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 ceramics are obtained at relatively lower temperature conditions (1850 °C).
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| first_indexed | 2024-12-22T17:16:22Z |
| format | Article |
| id | doaj.art-7e40212a99cf4d30b4f6312d89d28059 |
| institution | Directory Open Access Journal |
| issn | 1562-3920 2522-4867 |
| language | English |
| last_indexed | 2024-12-22T17:16:22Z |
| publishDate | 2021-11-01 |
| publisher | al-Farabi Kazakh National University |
| record_format | Article |
| series | Eurasian Chemico-Technological Journal |
| spelling | doaj.art-7e40212a99cf4d30b4f6312d89d280592022-12-21T18:18:58Zengal-Farabi Kazakh National UniversityEurasian Chemico-Technological Journal1562-39202522-48672021-11-0123310.18321/ectj1104Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy DiboridesS. Barbarossa0M. Murgia1R. Orrù2G. Cao3Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Unità di Ricerca del Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Università degli Studi di Cagliari, via Marengo 2, 09123 Cagliari, ItalyDipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Unità di Ricerca del Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Università degli Studi di Cagliari, via Marengo 2, 09123 Cagliari, ItalyDipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Unità di Ricerca del Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Università degli Studi di Cagliari, via Marengo 2, 09123 Cagliari, ItalyDipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Unità di Ricerca del Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Università degli Studi di Cagliari, via Marengo 2, 09123 Cagliari, Italy This paper is devoted to the celebration of 75 years’ jubilee of Professor Zulkhair Mansurov. One of the authors (Roberto Orrù) would like to acknowledge Zulkhair Mansurov for his vigorous effort given for the development and diffusion of the Eurasian Chemico-Technological Journal. The fabrication by Spark Plasma Sintering (SPS) of bulk high entropy ceramics from powders obtained by Self-propagating High temperature Synthesis (SHS) is addressed in this work. The effect produced by the introduction of 1 wt.% of graphite to the powders before SPS is investigated under different temperature conditions. The final density and composition of sintered (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 and (Hf0.2Mo0.2Zr0.2Ti0.2Nb0.2)B2 ceramics are found to be negatively affected by the presence of oxide impurities in the powders. While product composition can be progressively improved when the temperature is increased from 1800 to 1950 °C, residual porosities remain relatively high if using additive-free powders. In contrast, the introduction of 1 wt.%C markedly allows for oxides elimination by carbothermal reduction mechanism. Products consolidation is correspondingly enhanced so that relative densities of about 97% are attained. Other than the latter effect, surface oxides removal also makes powders more reactive, thus the synthesis of single-phase products is promoted. In particular, fully homogeneous (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 ceramics are obtained at relatively lower temperature conditions (1850 °C). https://ect-journal.kz/index.php/ectj/article/view/1104UHTCsHEBsoxidesgraphiteSPSSHS |
| spellingShingle | S. Barbarossa M. Murgia R. Orrù G. Cao Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides Eurasian Chemico-Technological Journal UHTCs HEBs oxides graphite SPS SHS |
| title | Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides |
| title_full | Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides |
| title_fullStr | Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides |
| title_full_unstemmed | Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides |
| title_short | Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides |
| title_sort | processing conditions optimization for the synthesis and consolidation of high entropy diborides |
| topic | UHTCs HEBs oxides graphite SPS SHS |
| url | https://ect-journal.kz/index.php/ectj/article/view/1104 |
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