Mechanisms responsible for enhancing low-temperature oxidation resistance of nonstoichiometric (Zr,Ti)C |
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| Authors: | Huilin Lun Junhao Yuan Yi Zeng Xiang Xiong Qing Wang Ziming Ye |
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| Affiliation: | 1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha, China;2. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian, China |
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| Abstract: | A series of (Zr,Ti)Cx (x = 0.7–1.0) samples were fabricated by a modified spark plasma sintering apparatus to investigate the effects of carbon concentration and Ti substitutions on the oxidation behavior. Crushed powders of (Zr,Ti)Cx were oxidized in lab air (N2–20-vol.% O2) from room temperature to 900°C. The results indicated that Zr0.8Ti0.2C0.8, with a nominal carbon concentration x = 0.8, displayed good oxidation resistance, which was attributed to the formation of dense t-(Zr,Ti)O2 oxide solid solution. During the oxidation of (Zr,Ti)Cx, Ti substitutions for Zr enhanced the outward diffusion of carbon, enabling a uniform carbon layer and a Zr–Ti–C–O layer on the surface of carbides. The formed carbon layer improved the oxidation resistance of (Zr,Ti)Cx below 550°C, where carbon is relatively oxidation resistant. Increasing the Ti concentration was found to enhance the oxidation resistance of (Zr,Ti)Cx with an increased oxidation onset temperature (672 ± 2°C for Zr0.8Ti0.2C0.8). |
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| Keywords: | carbides non-stoichiometric (Zr Ti)C oxidation behavior ultra-high temperature ceramics |
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