Abstract We demonstrate the deposition of Pt film on a nickel-based superalloy (CMSX-4) via a combination of galvanic displacement reaction and chemical reduction. The aqueous plating bath contains an optimized mixture of Pt precursor (H2PtCl6), pH adjuster (NaOH), and reducing agent (HCHO). Both time-evolved UV–Vis and X-ray absorption spectra on the plating bath indicate a sequential chemical reduction of Pt4+ → Pt2+ → Pt. In addition, a parasitic galvanic displacement reaction occurs in which Ni, Al, and Co from the CMSX-4 suffer from corrosive dissolution whereas the Pt4+ ions from the plating bath are reduced directly. This surface-mediated galvanic displacement reaction produces numerous Pt nanoparticles serving as the nucleation sites for chemical reduction of Pt4+ from HCHO. Therefore, typical sensitization and activation steps for electroless plating are not necessary in our plating bath. From X-ray diffraction pattern, the Pt film adopts a fcc polycrystalline structure. Images from scanning electron microscope confirm the formation of a dense and continuous Pt film with 1 μm thickness.

中文翻译：

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通过电置换反应和化学还原的组合在镍基高温合金上沉积铂

摘要 我们展示了通过电置换反应和化学还原的组合在镍基高温合金 (CMSX-4) 上沉积 Pt 薄膜。水性电镀浴包含 Pt 前体 (H2PtCl6)、pH 调节剂 (NaOH) 和还原剂 (HCHO) 的优化混合物。电镀浴上随时间演化的 UV-Vis 和 X 射线吸收光谱都表明 Pt4+ → Pt2+ → Pt 的顺序化学还原。此外，还会发生寄生电流置换反应，其中来自 CMSX-4 的 Ni、Al 和 Co 遭受腐蚀溶解，而来自镀浴的 Pt4+ 离子直接被还原。这种表面介导的电流置换反应产生大量 Pt 纳米粒子，作为从 HCHO 中化学还原 Pt4+ 的成核位点。所以，在我们的电镀槽中，化学镀的典型敏化和活化步骤不是必需的。从 X 射线衍射图可以看出，Pt 薄膜采用 fcc 多晶结构。来自扫描电子显微镜的图像证实了 1 μm 厚的致密连续 Pt 膜的形成。