Abstract

The effect of the anode material on the rate of electrodeposition of Fe−W alloy coatings from a citrate bath is studied. Both Fe and Ni soluble anodes and Pt and graphite insoluble anodes are addressed. The effects associated with the anode material are attributed to anodic oxidation of an Fe(II)−citrate complex involved in electrodeposition. In addition to its likely oxidation at the anode, this complex catalyzes reduction of W-containing species and acts as precursor to Fe deposition; these processes unfold via the formation of corresponding intermediates, their surface coverage determining the alloy composition. X-ray photoelectron spectroscopy characterization of deposited alloys indicates that the intermediate FeOH_ads is oxidized by water to form surface oxides. This process can explain the previously reported macroscopic size effect, i.e., the effect of the volume current density on the microhardness of deposited alloys. By using a soluble iron anode, we achieve an unprecedentedly high rate of alloy deposition (25 μm/h at a current density of 20 mA/cm²).

中文翻译：

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柠檬酸盐浴中Fe-W合金的电沉积：阳极材料的影响

摘要

研究了阳极材料对柠檬酸盐浴中Fe-W合金涂层电沉积速率的影响。涉及Fe和Ni可溶阳极以及Pt和石墨不溶阳极。与阳极材料相关的影响归因于参与电沉积的柠檬酸Fe（II）-络合物的阳极氧化。除了在阳极可能氧化外，这种络合物还催化还原含W物质，并作为Fe沉积的前体。这些过程通过形成相应的中间体而展开，它们的表面覆盖率决定了合金的成分。沉积合金的X射线光电子能谱法表征表明中间FeOH_广告被水氧化形成表面氧化物。该过程可以解释先前报道的宏观尺寸效应，即体积电流密度对沉积合金的显微硬度的影响。通过使用可溶性铁阳极，我们实现了前所未有的高合金沉积速率（电流密度为20 mA / cm ²时为25μm/ h ）。