Self-propagating high-temperature synthesis of nonstoichiometric wüstite
Self-propagating high-temperature synthesis of nonstoichiometric wüstite
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DOI：
10.1016/j.jallcom.2011.12.057
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发表时间：
2012-04
影响因子：
6.2
通讯作者：
Maki Hiramoto;N. Okinaka;T. Akiyama
中科院分区：
文献类型：
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作者：
Maki Hiramoto;N. Okinaka;T. Akiyama
本文描述了非化学计量 FexO (x=0.833–1) 的自蔓延高温合成 (SHS)，特别关注非化学计量 Fe 含量和稀释剂添加对 SHS 产物相的影响。在SHS工艺中，通过球磨将原料Fe、NaClO4（氧化剂）和NaCl（稀释剂）按照所需比例充分混合，随后对盘状生坯的下表面进行电点燃，通过持续放热反应的传播产生FexO。 X射线衍射分析表明SHS产物包含FexO和Fe3O4双相。与x=0.833的产物相比，0.947≤x≤1.00的产物的峰向较低角度移动，这是由于Fe缺陷导致晶体结构的晶格参数畸变。在 NaCl 稀释剂存在下，原材料在 SHS 过程中转化为高纯度 FexO 粉末。在没有 NaCl 稀释剂的情况下，SHS Fe0.947O 的晶格参数与理论晶格参数相对应。通过SHS无需额外外部加热即可获得非化学计量化合物FexO (0.942≤x≤0.952)。
This paper describes the self-propagating high-temperature synthesis (SHS) of nonstoichiometric FexO (x=0.833–1), with particular focus on the effects of nonstoichiometric Fe content and diluent addition on the phase of the SHS product. In the SHS process, the raw materials Fe, NaClO4(oxidizer), and NaCl (diluent) were thoroughly mixed in the desired ratio by ball milling, and the lower surfaces of the disk-shaped green compacts were subsequently electrically ignited to produce FexO through the propagation of the sustainable exothermic reaction. X-ray diffraction analysis showed that the SHS products comprised double phases of FexO and Fe3O4. The peaks of products with 0.947≤x≤1.00 shifted to lower angles in comparison to those of the product with x=0.833 attributed to the lattice parameter distortion of the crystal structure because of the Fe defects. In the presence of the NaCl diluent, the raw materials were converted to high-purity FexO powders during the SHS process. Without the NaCl diluent, the lattice parameter of SHS Fe0.947O corresponded to the theoretical lattice parameter. Nonstoichiometric compounds of FexO (0.942≤x≤0.952) were obtained through SHS without additional external heating.