Abstract According to the PEO coatings remarkable properties, this surface process is extensively used in order to modify the surface and improve the properties of valve metals and their alloys. However, few articles about PEO treatment on niobium have been published. This study reviews effects of electrolyte composition and different voltages on the surface behaviors of formed PEO coatings on niobium. The PEO treatment of niobium in silicate electrolytes showed this procedure enables the accommodation of Si in the oxide coatings. The PEO procedure indicated that the oxide layers that were produced before the breakdown of 0.1 M H3PO4 solution are amorphous, whereas after the breakdown they become fairly crystalline and mostly consisted of Nb2O5. The PEO procedure in Ca- and P-containing electrolytes showed that the voltage has an important effect on the sparks nature that were produced within the growth of oxide and the properties of the coatings highly depend on the kind of sparks. Also, corrosion behavior of the PEO coatings in these electrolytes do not only depend on the coating thickness but also its structure is controlled by the spark regime. Finally, the PEO procedure of Nb in silicate-, phosphate- and aluminate-based solutions indicated that the corrosion resistance declines in the order of phosphate-> aluminate-> silicate-based solutions.

中文翻译：

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铌的等离子体电解氧化（PEO）研究进展：机理、性能和应用

摘要 由于PEO涂层的显着性能，该表面处理被广泛用于对阀门金属及其合金进行表面改性和提高性能。然而，关于铌的 PEO 处理的文章很少发表。本研究回顾了电解质组成和不同电压对形成的 PEO 涂层在铌上的表面行为的影响。硅酸盐电解质中铌的 PEO 处理表明该程序能够在氧化物涂层中容纳 Si。PEO 程序表明，在 0.1 M H3PO4 溶液击穿之前产生的氧化层是无​​定形的，而击穿后它们变得相当结晶，主要由 Nb2O5 组成。含钙和含磷电解质中的 PEO 程序表明，电压对氧化物生长过程中产生的火花性质有重要影响，涂层的性能高度依赖于火花的种类。此外，这些电解质中 PEO 涂层的腐蚀行为不仅取决于涂层厚度，而且其结构受火花状态控制。最后，Nb 在硅酸盐、磷酸盐和铝酸盐基溶液中的 PEO 过程表明，耐腐蚀性能按照磷酸盐-> 铝酸盐-> 硅酸盐基溶液的顺序下降。PEO 涂层在这些电解质中的腐蚀行为不仅取决于涂层厚度，而且其结构受火花状态控制。最后，Nb 在硅酸盐、磷酸盐和铝酸盐基溶液中的 PEO 过程表明，耐腐蚀性能按照磷酸盐-> 铝酸盐-> 硅酸盐基溶液的顺序下降。PEO 涂层在这些电解质中的腐蚀行为不仅取决于涂层厚度，而且其结构受火花状态控制。最后，Nb 在硅酸盐、磷酸盐和铝酸盐基溶液中的 PEO 过程表明，耐腐蚀性能按照磷酸盐-> 铝酸盐-> 硅酸盐基溶液的顺序下降。