This contribution analyzes the electrochemical etching of copper in a sodium nitrate electrolyte using Raman spectroscopy. Experiments were conducted in a specially designed process chamber at voltages below, at, and above the limiting current plateau. Below the plateau, a Raman peak at 1050 cm is detected, which is attributed to the symmetrical nitrate ion. However, the line shape changes at and above the plateau. Detailed line shape analysis indicates the presence of a copper nitrate surface film by comparison with copper nitrate solutions. In addition, the conductivity and pH of copper nitrate solutions were determined. A 5 M copper nitrate solution exhibits a low conductivity of 55 mS cm and a pH close to 0. A significant influence, especially of the low pH, on the surface structure and therefore on the etching mechanism is assumed.

中文翻译：

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硝酸盐电解液中铜电化学加工过程中表面薄膜存在的原位证据


该贡献使用拉曼光谱分析了硝酸钠电解质中铜的电化学蚀刻。实验是在专门设计的处理室中在低于、等于和高于极限电流平台的电压下进行的。在平台下方，检测到 1050 cm 处的拉曼峰，这归因于对称的硝酸根离子。然而，线的形状在平台处和平台上方发生变化。通过与硝酸铜溶液的比较，详细的线形分析表明存在硝酸铜表面膜。此外，还测定了硝酸铜溶液的电导率和pH值。 5 M 硝酸铜溶液表现出 55 mS cm 的低电导率和接近 0 的 pH 值。假设对表面结构以及蚀刻机制有显着影响，尤其是低 pH 值。