Cu-Ni-Fe-coated and bare aluminum bronze materials are evaluated as O2-evolving anodes for Al production in low-temperature (700 °C) potassium-based cryolite. The Cu-Ni-Fe coating (~ 0.8 mm thick) is obtained by cold spraying of mechanically alloyed Cu65Ni20Fe15 (wt.%) powder and presents a biphase Cu-rich/Ni-Fe-rich structure. The composition and morphology of the scale formed on both anodes are characterized after different electrolysis times (3 to 50 h). In both cases, the formed surface oxide is porous with significant electrolyte infiltration. However, for the Cu-Ni-Fe-coated anode, there is formation of an inner NiFe2O4-rich layer limiting the outward Cu diffusion at the anode surface. As a result after 50 h of electrolysis, a lower anode wear rate (0.37 versus 3.8 cm year−1) and a higher produced Al purity (98.8 versus 95.4 wt.%) are observed with the Cu-Ni-Fe-coated anode compared to the uncoated aluminum bronze anode.

中文翻译：

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用于无 CO2 铝生产的冷喷涂 Cu-Ni-Fe 阳极

Cu-Ni-Fe 涂层和裸铝青铜材料被评估为用于在低温 (700 °C) 钾基冰晶石中生产铝的 O2 析出阳极。Cu-Ni-Fe 涂层（~ 0.8 mm 厚）是通过机械合金化 Cu65Ni20Fe15 (wt.%) 粉末的冷喷涂获得的，呈现出双相富 Cu/富 Ni-Fe 结构。在不同的电解时间（3 至 50 小时）后，表征在两个阳极上形成的水垢的组成和形态。在这两种情况下，形成的表面氧化物都是多孔的，电解质渗透显着。然而，对于 Cu-Ni-Fe 涂层阳极，形成了一个富含 NiFe2O4 的内部层，限制了阳极表面上的铜向外扩散。因此，电解 50 小时后，阳极磨损率较低（0.37 与 3.8 cm year-1）和更高的铝纯度（98.8 与 95.4 wt.