The reduction of niobium and tantalum pentoxides by silicon in vacuum
The reduction of niobium and tantalum pentoxides by silicon in vacuum
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DOI：
10.1016/s0925-8388(00)01274-3
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发表时间：
2001-02-09
影响因子：
6.2
通讯作者：
Garg, SP
中科院分区：
文献类型：
--
作者：
Awasthi, A;Bhatt, YJ;Garg, SP
研究了在高温真空条件下用硅作还原剂还原Nb_2O_5和Ta_2O_5得到金属的方法。由于通过挥发性一氧化硅SiO（v）的蒸发除去氧而发生还原。利用已发表的热力学数据绘制了Nb-Si-O和Ta-Si-O体系的Pourbaix-Ellingham图。通过真空热重实验和产物的X射线衍射（XRD）分析，也观察到了这些图所示的还原顺序。对于铌和钽系统，还原在1150 ℃左右开始，并且随着温度在真空下升高到1600 ℃而平稳地进行。还原的程度被认为是超过在碳热还原在可比的温度，压力和持续时间的水平观察。产物为Nb-Si-O或Ta-Si-O合金，其可通过高温真空处理精炼为纯金属。(C)2001 Elsevier Science B. V.保留所有权利。
The use of silicon as a reducing agent for Nb2O5 and Ta2O5 to obtain the metals under pyrovacuum conditions has been investigated. Reduction occurs due to the removal or oxygen by evaporation of volatile silicon monoxide, SiO(v). Pourbaix-Ellingham diagrams for Nb-Si-O and Ta-Si-O systems were constructed using the published thermodynamic data. The sequences of reduction, as indicated by these diagrams, were also observed by vacuum thermogravimetry experiments and X-ray diffraction (XRD) analysis of products. The reduction starts at around 1150 degreesC for both niobium and tantalum systems and proceeds smoothly as the temperature is raised to 1600 degreesC under vacuum. Thr extents of reduction were found to be more than that observed in carbothermic reductions at comparable levels of temperature, pressure and durations. The product was an Nb-Si-O or Ta-Si-O alloy, which is refineable to the pure metal by pyrovacuum treatment at a higher temperature. (C) 2001 Elsevier Science B.V. All rights reserved.