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Microstructural evolution of Si(HfₓTa₁₋ₓ)(C)N polymer-derived ceramics upon high-temperature anneal

Thor, Nathalie ORCID iD icon 1; Bernauer, Jan 1; Petry, Nils-Christian 1; Ionescu, Emanuel 1; Riedel, Ralf 1; Pundt, Astrid 1,2; Kleebe, Hans-Joachim 1
1 Graduiertenkolleg 2561: Materials Compounds from Composite Materials (GRK 2561), Karlsruher Institut für Technologie (KIT)
2 Institut für Angewandte Materialien – Werkstoffkunde (IAM-WK), Karlsruher Institut für Technologie (KIT)


Ultra-high temperature ceramic nanocomposites (UHTC-NC) within the Si(HfxTa1−x)(C)N system were synthesized via the polymer-derived ceramics (PDC) synthesis route. The microstructure evolution of the materials was investigated upon pyrolysis and subsequent heat treatment. The crystallization behavior and phase composition were studied utilizing X-ray diffraction, scanning- and transmission electron microscopy. Single-source-precursors were converted into amorphous single-phase ceramics, with the exception of surface crystallization effects, at 1000 °C in NH3. Annealing in N2 at 1600 °C resulted in fully crystalline UHTCs. The powder samples revealed microstructures consisting of two characteristic regions, bulk and surface; displaying intrinsic microstructure and phase composition differences. Instead of the expected nitrides, transition metal carbides (TMC) were detected upon high-temperature anneal. The residual carbon available in the system triggered a decomposition reaction, resulting in the formation of TMCs plus gaseous nitrogen and SiC. Experimental data underline that N-containing PDCs are prone to phase separation accompanied by thermal decomposition and diffusion-controlled coarsening.

DOI: 10.1016/j.jeurceramsoc.2022.11.060
Zitationen: 10
Zitationen: 10
Zugehörige Institution(en) am KIT Graduiertenkolleg 2561: Materials Compounds from Composite Materials (GRK 2561)
Institut für Angewandte Materialien – Werkstoffkunde (IAM-WK)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 12.2022
Sprache Englisch
Identifikator ISSN: 0955-2219
KITopen-ID: 1000153468
HGF-Programm 38.05.01 (POF IV, LK 01) Anthropogenic Carbon Cycle
Erschienen in Journal of the European Ceramic Society
Verlag Elsevier
Band 43
Heft 4
Seiten 1417-1431
Projektinformation GRK 2561; MatCom-ComMat (DFG, DFG KOORD, GRK 2561/1 - 2020)
Vorab online veröffentlicht am 26.11.2022
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