| 引用本文: | 刘璐琪,尹玉莹,黄美茹,马付良,曾志翔.多孔吸液芯的多步电沉积法制备及其结合性能[J].中国表面工程,2024,37(6):354~363 |
| LIU Luqi,YIN Yuying,HUANG Meiru,MA Fuliang,ZENG Zhixiang.Bonding Performance and Preparation of Porous Wick via Multistep Electrodeposition[J].China Surface Engineering,2024,37(6):354~363 |
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| 摘要: |
| 氢气泡模板法电沉积技术制备的多孔金属薄膜具有孔隙率高、密度小和成本低的特点，已被广泛用于电化学电容器和储能等领域。近年来，该技术被应用于制备均热板中的吸液芯，旨在得到具有高毛细性能的超薄多孔吸液芯镀层。 但高孔隙率金属镀层的结合力不足的问题尚未得到充分研究和解决。采用多步电沉积法制备出多孔的 CuNi 吸液芯镀层，通过 SEM、XRD、EDS 和 3D 轮廓仪表征多孔镀层的形貌、化学组成和表面粗糙度。采用划格测试和超声测试分别研究 Cu 镀层以及 CuNi 镀层的结合性能。除此以外，对比 Cu 镀层和 CuNi 镀层的润湿性。结果表明：与 Cu 镀层相比，形成 Cu-Ni 固溶体的 CuNi 镀层的结合性能得到提升。经过 30 min 的超声测试，CuNi 镀层的质量损失率（0.61%） 远远低于 Cu 镀层的质量损失率（2.58%）。而且，CuNi 镀层的水滴铺展速率和水爬升速率并未降低。水在 CuNi 镀层 （＜60 μm）上具有 0.43 mm / s 的爬升速率，并可在 0.2 s 内完全铺展。采用多步电沉积法制备具有强结合性能的 CuNi 多孔镀层，可为开发稳定高效的均热板提供新的技术途径。 |
| 关键词: 电沉积 多孔吸液芯 均热板 结合 毛细 |
| DOI：10.11933/j.issn.1007-9289.20240102001 |
| 分类号:TQ153；O614 |
| 基金项目:国家自然科学基金（52105229） |
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| Bonding Performance and Preparation of Porous Wick via Multistep Electrodeposition |
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LIU Luqi1，2，YIN Yuying1，3，HUANG Meiru1，3，MA Fuliang1，ZENG Zhixiang1
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1.Key Laboratory of Advanced Marine Materials, Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences, Ningbo 315201 , China ；2.College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences,Beijing 100049 , China ；3.School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 , China
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| Abstract: |
| The hydrogen-bubble template method is widely used to create porous metal films owing to its high porosity, low density, and low cost. This technology has been applied in various fields, including electrochemistry and energy storage. Recently, it has been innovatively utilized to create porous wicks for vapor chambers to produce ultrathin porous coatings with high capillary performance. However, the subpar mechanical stability of porous wicks hinders efficient two-phase heat transfer from the vapor chamber. The issue of insufficient bonding in high-porosity metal coatings has not been comprehensively investigated or resolved. Hence, a multistep electrodeposition process followed by heat treatment at 500 ℃ is performed to achieve porous CuNi coatings. First, a porous Cu coating is deposited onto a brass substrate. Hydrogen and copper ions reduce simultaneously at the cathode in acidic and overpotential environments. Hydrogen bubbles formed separately from the plating solution serve as a dynamic model that affects the growth of copper particles, thus resulting in the formation of a porous copper coating. Subsequently, a nickel coating is deposited electrochemically and then exposed to 500 ℃ to achieve a CuNi coating. Scanning electron microscopy and energy-dispersive X-ray spectroscopy results show that the copper branch crystals are intertwined and arranged in a honeycomb structure, with a combination of large and small pores. The metal coating, which comprises fine Ni particles, uniformly shielded the porous Cu surfaces. Three-dimensional profilometry is performed to evaluate the surface roughness and thickness of the CuNi coating. The surface roughness (arithmetic mean deviation=12.6 μm) and thickness (59.8 μm) of the CuNi coating are higher than those of porous Cu coatings. Nevertheless, the thickness of the CuNi coating is much lower than that of the wick in most ultrathin vapor chambers. X-ray diffraction analysis show that the Cu and Ni in the CuNi coatings formed a solid solution, thus enhancing the bonding performance of the coatings. To characterize the bonding performance, grid and ultrasonic tests are performed on Cu and CuNi coatings. Referring to the international standard ASTM D3359, a grid test is performed to qualitatively assess the bonding strength of the metal coating, and a tape-tear test is conducted to visually demonstrate the bonding strength. Compared with an unannealed Cu-25 ℃ coating, the Cu coating does not exhibit lumpy removal after tape tearing and satisfies the 5B level. This suggests that annealing improves the coating bonding. Less metal-powder shedding on the CuNi coating indicates its stronger bond. During ultrasonic testing, the extent of damage to the coating is quantified by calculating the mass loss and mass-loss rate of the coating to further evaluate the bond strength. After 30 min of ultrasonic oscillation, the results show that the mass-loss rate of the CuNi coating (0.61%) is significantly lower than that of the Cu coating (2.58%). Ultrasonic tests further demonstrate the superior bonding performance of the CuNi coating. In addition to the improved bonding performance, the enhanced wettability and capillary performance of the CuNi coating are validated through contact-angle and capillary-rise tests. Based on observations, a 3 μL water droplet disperses completely on the surface of the CuNi coating in 0.2 s. Additionally, water ascends on the CuNi coating at a speed of 0.43 mm / s. This phenomenon is primarily due to the significant roughness of the CuNi coating, which enhances the hydrophilicity and capillary force of the porous coating. The formation of ultrathin porous CuNi coatings with excellent bonding and capillary properties via a series of electrodeposition steps can revolutionize the production of stable and efficient vapor chambers. This innovation can increase thermal-management capabilities across a wide range of industries. |
| Key words: electrodeposition porous wick vapor chamber bonding capillary |
