Corrosion behavior of the nickel/nickel interface during the copper‐sacrificial layer release process in micro‐electroforming
Corrosion behavior of the nickel/nickel interface during the copper‐sacrificial layer release process in micro‐electroforming
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DOI：
10.1002/maco.202112815
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发表时间：
2021-04
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影响因子：
--
通讯作者：
Lili Wang;M. Ye;Yingying Wang;Dong Tian;Zuoyan Ye;Chao Wang
中科院分区：
文献类型：
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作者：
Lili Wang;M. Ye;Yingying Wang;Dong Tian;Zuoyan Ye;Chao Wang
研究了多层微电铸中铜牺牲层释放过程中镍/镍（Ni/Ni）界面的腐蚀行为。通过改变多层微电铸的预处理和后处理（电镀、原位阳极处理、酸洗、再钝化和热处理），获得了六种不同类型的Ni/Ni界面。通过开路电位和X射线光电子能谱研究了预处理的Ni基底的活性和表面特性。采用扫描电镜对制备的Ni/Ni界面的微观结构进行了测定;在氯化铁溶液中释放牺牲层后，在超景深三维显微镜下观察其腐蚀形貌和腐蚀深度。Ni/Ni界面显示出预先存在的钝化层和界面缺陷。界面比镍基地更容易被攻击。沿着界面边界的点蚀通过三个主要过程发生--萌生、生长和点蚀合并--并相应降低界面粘附强度，最终降低结构完整性。基体改性（酸洗和酸洗）和热后处理的组合有效地避免了局部腐蚀。我们相信表面活化和热致扩散已经起作用。
This study investigates the corrosion behavior of the nickel/nickel (Ni/Ni) interface during the release of the copper‐sacrificial layer in multilayered micro‐electroforming. By altering the pre‐ and posttreatment of multilayered micro‐electroforming (degreasing, in situ anodic treatment, pickling, repassivation, and heat treatment), six different types of Ni/Ni interfaces were obtained. The activities and surface characteristics of the pretreated Ni substrates were investigated via open circuit potential and X‐ray photoelectron spectroscopy. The microstructures of the as‐prepared Ni/Ni interfaces were determined using scanning electron microscopy; after releasing the sacrificial layer in the ferric chloride solution, their corrosion morphologies and corrosion depths were observed under a three‐dimensional microscope with an ultra‐depth of field. The Ni/Ni interface showed a pre‐existing passive layer and interfacial defects. The interface was more prone to attack than the Ni base. Pitting corrosion along the interface boundary occurs via three main processes—initiation, growth, and pit coalescence—with a corresponding reduction in the interfacial adhesion strength and ultimately the structural integrity. The combination of substrate modification (degreasing and pickling) and heat posttreatment effectively avoids localized corrosion. We believe that the surface activation and thermally induced diffusion have worked.