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Solid-Solution Effects on the High-Temperature Oxidation Behavior of Polymer-Derived (Hf,Ta)C/SiC and (Hf,Ti)C/SiC Ceramic Nanocomposites

Wen, Qingbo and Riedel, Ralf and Ionescu, Emanuel (2019):
Solid-Solution Effects on the High-Temperature Oxidation Behavior of Polymer-Derived (Hf,Ta)C/SiC and (Hf,Ti)C/SiC Ceramic Nanocomposites.
In: Advanced Engineering Materials, Wiley VCH, Weinheim, Germany, p. 1800879, 21, (5), ISSN 14381656,
DOI: 10.1002/adem.201800879,
[Online-Edition: https://doi.org/10.1002/adem.201800879],
[Article]

Abstract

In the present study, two concepts to improve the oxidation resistance at high‐temperatures of ceramic nanocomposites consisting of 85–90 vol% SiC, 5–8 vol% group IV metal carbides (i.e., HfC, TaC), and 5–7 vol% carbon are introduced and discussed. First improvement concept relates to the passivation of the samples upon short‐term oxidation at 1400 °C (30 min). This is a critical step, especially with respect to silica formation, which is relatively sluggish at temperatures lower than 1000–1200 °C. Moreover, solid‐solution metal carbides (Hf,Ta)C and (Hf,Ti)C are shown to be clearly more oxidation resistant than the binary HfC and TaC phases. Whereas, the solid‐solution effect contributes to a significant improvement of the short‐term oxidation resistance of the studied nanocomposites, the passivation of the materials prior exposure of high‐temperature oxidation conditions provides a remarkably improved long‐term behavior thereof. Possible mechanisms involved in the oxidation processes of (Hf,Ta)C/SiC and (Hf,Ti)/SiC ceramic nanocomposites are highlighted and critically assessed.

Item Type: Article
Erschienen: 2019
Creators: Wen, Qingbo and Riedel, Ralf and Ionescu, Emanuel
Title: Solid-Solution Effects on the High-Temperature Oxidation Behavior of Polymer-Derived (Hf,Ta)C/SiC and (Hf,Ti)C/SiC Ceramic Nanocomposites
Language: English
Abstract:

In the present study, two concepts to improve the oxidation resistance at high‐temperatures of ceramic nanocomposites consisting of 85–90 vol% SiC, 5–8 vol% group IV metal carbides (i.e., HfC, TaC), and 5–7 vol% carbon are introduced and discussed. First improvement concept relates to the passivation of the samples upon short‐term oxidation at 1400 °C (30 min). This is a critical step, especially with respect to silica formation, which is relatively sluggish at temperatures lower than 1000–1200 °C. Moreover, solid‐solution metal carbides (Hf,Ta)C and (Hf,Ti)C are shown to be clearly more oxidation resistant than the binary HfC and TaC phases. Whereas, the solid‐solution effect contributes to a significant improvement of the short‐term oxidation resistance of the studied nanocomposites, the passivation of the materials prior exposure of high‐temperature oxidation conditions provides a remarkably improved long‐term behavior thereof. Possible mechanisms involved in the oxidation processes of (Hf,Ta)C/SiC and (Hf,Ti)/SiC ceramic nanocomposites are highlighted and critically assessed.

Journal or Publication Title: Advanced Engineering Materials
Volume: 21
Number: 5
Publisher: Wiley VCH, Weinheim, Germany
Uncontrolled Keywords: hafnium carbide, high‐temperature oxidation, passivation, solid solution, ultrahigh‐temperature ceramic nanocomposites
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
Date Deposited: 23 Jan 2019 08:10
DOI: 10.1002/adem.201800879
Official URL: https://doi.org/10.1002/adem.201800879
Funders: Financial support from the German Science Foundation (DFG; Bonn, Germany) was gratefully acknowledged., Financial support from the &D Convergence Program of MSIP (Ministry of Science, ICT and Future Planning) and NST (National Research Council of Science & Technology) of Republic of Korea (Grant: CMIP‐13‐4‐KIMS) were gratefully acknowledged.
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