We investigated the conditions for low-temperature synthesis of ZrC fine powder from ZrO
2–Mg–CH
4. The synthesis utilizes a thermite-type reaction, with Mg as the reducing agent, and a reaction between Mg and CH
4 gas as a carbon source. The Mg/ZrO
2 molar ratio as well as the heating rate were varied. Because C can be continuously fed into the reaction group by the cyclic reaction of Mg through the formation and decomposition of Mg
2C
3 (2Mg + 3CH
4→ Mg
2C
3+ 6H
2→ 2Mg + 3C), a molar ratio of 2.2 for Mg/ZrO
2 was sufficient for the synthesis of single-phase ZrC. ZrC powders were synthesized under the following conditions: Mg/ZrO
2 molar ratio = 2.2, heating rate = 20°C/min, and temperature maintained at 750°C for 30 min. The amount of reaction heat produced in the reduction reaction of ZrO
2 by Mg depended on the Mg/ZrO
2 molar ratio, specifically, the amount of ZrO
2 contained. Moreover, the cyclic reaction of Mg-Mg
2C
3–Mg was influenced by the amount of reaction heat described above and by the heating rate. The ZrC fine powder showed little aggregation and high dispersibility.
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