Electrodeposition of tungsten from ZnCl2–NaCl–KCl–KF–WO3 melt and investigation on tungsten species in the melt
Electrodeposition of tungsten from ZnCl2–NaCl–KCl–KF–WO3 melt and investigation on tungsten species in the melt
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DOI：
10.1016/j.electacta.2009.10.021
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发表时间：
2010
影响因子：
6.6
通讯作者：
K. Nitta;T. Nohira;R. Hagiwara;M. Majima;Shin'ji Inazawa
中科院分区：
文献类型：
--
作者：
K. Nitta;T. Nohira;R. Hagiwara;M. Majima;Shin'ji Inazawa
为了获得更厚的镀层，进一步研究了在250℃时，在氯化锌-氯化钠-氯化钾-氟化钾-三氧化二钨熔体中电沉积钨。在0.08V的普通电解液中，6h后电流密度由1.2mAcm−~2降至0.3mAcm−~2。得到的钨层厚度为2.1μm，电流效率估计为93%。熔融6h后取上清盐和底盐，用电感耦合等离子体原子发射光谱仪和X射线衍射仪进行分析。发现在熔体中，可溶的钨物种慢慢地转变为不溶的钨物种。可溶物种为WO3F-−阴离子。其中一种不溶物被确认为ZnWO4，另一种被认为是K2WO2F4。除每隔2小时间歇加入WO_3外，在相同条件下进行电沉积。电流密度保持在初始值，厚度为4.2μm，断续加入WO_3是获得较厚钨膜的有效方法。
The electrodeposition of tungsten in ZnCl2–NaCl–KCl–KF–WO3melt at 250°C was further studied to obtain a thicker deposit. In the ordinary electrolysis at 0.08V vs. Zn(II)/Zn, the current density decreased from 1.2mAcm−2to 0.3mAcm−2in 6h. A thickness of the obtained tungsten layer was 2.1μm and the estimated current efficiency was 93%. A supernatant salt and a bottom salt were sampled after 6h from the melting and were analyzed by ICP-AES and XRD. It was found that the soluble tungsten species slowly changes to insoluble ones in the melt. The soluble species was suggested to be WO3F−anion. One of the insoluble species was confirmed to be ZnWO4and the other one was suggested to be K2WO2F4. Electrodeposition was carried out under the same condition as above except for the intermittent addition of WO3every 2h. The current density was kept at the initial value and the thickness was 4.2μm. The intermittent addition of WO3was confirmed to be effective to obtain a thicker tungsten film.