Preparation conditions and formation process of ZrC/Al
2O
3 composite powders from the ZrO
2-Al-carbon black or ZrO
2-CH
4 system were examined. The ZrC/Al
2O
3 fine composite powders were prepared from the former system by heating the powder mixture of ZrO
2:Al:C molar ratio=3:4:3 at 950°-1000°C for 1h. The formation process of the ZrC/Al
2O
3 Composite powders was composed of three main reactions: (i) the reduction of ZrO
2 With Al and the formation of Al
2O
3, (ii) the formation of Al
3Zr With Zr and Al, and (iii) the decomposition of Al3Zr with carbon black and the formation of ZrC. The process (i) was interfered by the process (ii). Al
4C
3 was not formed by the process (m). On the other hand, in case of the ZrO
2-Al-CH
4 system, preparation of ZrC/Al
2O
3 composite powder was difficult because of Al
2C
3 and ZrC were formed by reaction between Al
3Zr and CH
4. For the preparation of the ZrC/Al
2O
3 composite powder, it was most important to suppress the formation of Al
4C
3 by controlling the reactivity between Al and carbon source.
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