Thor, Nathalie ; Bernauer, Jan ; Petry, Nils-Christian ; Ionescu, Emanuel ; Riedel, Ralf ; Pundt, Astrid ; Kleebe, Hans-Joachim (2023)
Microstructural evolution of Si(HfxTa1−x)(C)N polymer-derived ceramics upon high-temperature anneal.
In: Journal of the European Ceramic Society, 43 (4)
doi: 10.1016/j.jeurceramsoc.2022.11.060
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Ultra-high temperature ceramic nanocomposites (UHTC-NC) within the Si(HfxTa1_x)(C)N system were synthe-sized 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 degrees C in NH3. Annealing in N2 at 1600 degrees C resulted in fully crystalline UHTCs. The powder samples revealed microstructures consisting of two characteristic regions, bulk and surface; displaying intrinsic micro-structure 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 decom-position 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.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2023 |
| Autor(en): | Thor, Nathalie ; Bernauer, Jan ; Petry, Nils-Christian ; Ionescu, Emanuel ; Riedel, Ralf ; Pundt, Astrid ; Kleebe, Hans-Joachim |
| Art des Eintrags: | Bibliographie |
| Titel: | Microstructural evolution of Si(HfxTa1−x)(C)N polymer-derived ceramics upon high-temperature anneal |
| Sprache: | Englisch |
| Publikationsjahr: | April 2023 |
| Verlag: | Elsevier |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Journal of the European Ceramic Society |
| Jahrgang/Volume einer Zeitschrift: | 43 |
| (Heft-)Nummer: | 4 |
| DOI: | 10.1016/j.jeurceramsoc.2022.11.060 |
| Kurzbeschreibung (Abstract): | Ultra-high temperature ceramic nanocomposites (UHTC-NC) within the Si(HfxTa1_x)(C)N system were synthe-sized 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 degrees C in NH3. Annealing in N2 at 1600 degrees C resulted in fully crystalline UHTCs. The powder samples revealed microstructures consisting of two characteristic regions, bulk and surface; displaying intrinsic micro-structure 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 decom-position 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. |
| Freie Schlagworte: | polymer-derived ceramic, electron microscopy thermal decomposition, UHTC, transition metal carbide, source-precusor synthesis, oxidation behavior, nanocomposites, decomposition, Hafnium, TAC, polysilzane, composites, resistance, reduction |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Geowissenschaften > Fachgebiet Geomaterialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe |
| Hinterlegungsdatum: | 26 Jan 2023 06:32 |
| Letzte Änderung: | 26 Jan 2023 06:32 |
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