Ceramiche ultra refrattarie

Le ceramiche ultra refrattarie o Ultra-high-temperature ceramics (UHTCs) sono una classe di ceramiche refrattarie che offrono un'eccellente stabilità a temperature superiori a 2000 °C^[1] studiate come possibili materiali di protezione termica (TPS), rivestimenti per materiali soggetti a temperature elevate e materiali monolitici per elementi riscaldanti. In generale, gli UHTC sono boruri, carburi, nitruri e ossidi dei metalli di transizione dei primi gruppi (III-V). Gli attuali sforzi si sono concentrati su boruri di metalli di transizione pesanti come il diboruro di afnio (HfB₂) e il diboruro di zirconio (ZrB₂);^[2]^[3] ulteriori UHTC studiati per applicazioni come TPS includono nitruro di afnio (HfN),^[4] nitruro di zirconio (ZrN),^[5] carburo di titanio (TiC),^[6] nitruro di titanio (TiN), diossido di torio (ThO₂),^[7]^[8] carburo di tantalio (TaC) e loro compositi associati.^[9]

^ (EN) Wuchina, E., UHTCs: ultra-high temperature ceramic materials for extreme environment applications, in The Electrochemical Society Interface, vol. 16, 2007, p. 30.
^ (EN) Zhang, Guo-Jun, Ultrahigh temperature ceramics (UHTCs) based on ZrB₂ and HfB₂ systems: Powder synthesis, densification and mechanical properties, in Journal of Physics: Conference Series, vol. 176, 2009.
^ (EN) Lawson, John W., Murray S. Daw e Charles W. Bauschlicher, Lattice thermal conductivity of ultra high temperature ceramics ZrB₂ and HfB₂ from atomistic simulations, in Journal of Applied Physics, vol. 110, 2011, pp. 083507-083507, DOI:10.1063/1.3647754.
^ (EN) Monteverde, Frédéric e Alida Bellosi, Efficacy of HfN as sintering aid in the manufacture of ultrahigh-temperature metal diborides-matrix ceramics, in Journal of Materials Research and Technology, vol. 19, 2004, pp. 3576-3585, DOI:10.1557/jmr.2004.0460.
^ (EN) Zhao, Hailei, In situ synthesis mechanism of ZrB2-ZrN composite, in Materials Science and Engineering: A, vol. 452, 2007, pp. 130-134.
^ (EN) Zhu, Chun-Chen, Xing-Hong Zhang e Xiao-Dong He, Self-propagating High-temperature Synthesis of TiC-TiB₂/Cu Ceramic-matrix Composite, in Journal of Inorganic Materials, vol. 4, 2003, p. 026.
^ (EN) Chen, TJ, Fracture characteristic of ThO₂ ceramics at high-temperature, in American Ceramic Society Bulletin, vol. 60, 1981, p. 923.
^ (EN) Curtis, C E. e J.R. Johnson, Properties of thorium oxide ceramics, in Journal of the American Ceramic Society, vol. 40, 1957, pp. 63-68, DOI:10.1111/j.1151-2916.1957.tb12576.x.
^ (EN) Sannikova, S.N., T. A. Safronova e E.S. Lukin, The effect of a sintering method on the properties of high-temperature ceramics, in Refractories and Industrial Ceramics, vol. 47, 2006, pp. 299-301, DOI:10.1007/s11148-006-0113-y.

[Reference1-1] (EN) Wuchina, E., UHTCs: ultra-high temperature ceramic materials for extreme environment applications, in The Electrochemical Society Interface, vol. 16, 2007, p. 30.

[Reference39-2] (EN) Zhang, Guo-Jun, Ultrahigh temperature ceramics (UHTCs) based on ZrB₂ and HfB₂ systems: Powder synthesis, densification and mechanical properties, in Journal of Physics: Conference Series, vol. 176, 2009.

[reference3-3] (EN) Lawson, John W., Murray S. Daw e Charles W. Bauschlicher, Lattice thermal conductivity of ultra high temperature ceramics ZrB₂ and HfB₂ from atomistic simulations, in Journal of Applied Physics, vol. 110, 2011, pp. 083507-083507, DOI:10.1063/1.3647754.

[Reference4-4] (EN) Monteverde, Frédéric e Alida Bellosi, Efficacy of HfN as sintering aid in the manufacture of ultrahigh-temperature metal diborides-matrix ceramics, in Journal of Materials Research and Technology, vol. 19, 2004, pp. 3576-3585, DOI:10.1557/jmr.2004.0460.

[Reference5-5] (EN) Zhao, Hailei, In situ synthesis mechanism of ZrB2-ZrN composite, in Materials Science and Engineering: A, vol. 452, 2007, pp. 130-134.

[Reference6-6] (EN) Zhu, Chun-Chen, Xing-Hong Zhang e Xiao-Dong He, Self-propagating High-temperature Synthesis of TiC-TiB₂/Cu Ceramic-matrix Composite, in Journal of Inorganic Materials, vol. 4, 2003, p. 026.

[Reference7-7] (EN) Chen, TJ, Fracture characteristic of ThO₂ ceramics at high-temperature, in American Ceramic Society Bulletin, vol. 60, 1981, p. 923.

[Reference8-8] (EN) Curtis, C E. e J.R. Johnson, Properties of thorium oxide ceramics, in Journal of the American Ceramic Society, vol. 40, 1957, pp. 63-68, DOI:10.1111/j.1151-2916.1957.tb12576.x.

[Reference10-9] (EN) Sannikova, S.N., T. A. Safronova e E.S. Lukin, The effect of a sintering method on the properties of high-temperature ceramics, in Refractories and Industrial Ceramics, vol. 47, 2006, pp. 299-301, DOI:10.1007/s11148-006-0113-y.

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