Research Status on Anticorrosion Coating for Copper and Copper Alloys
Citations
Li Jie,Yang Yang,Wu Ping,Zhu Dehao,Liang Yan,Pu Xinran,Liu Jing,Wen Jiaxin. Research status on anticorrosion coating for copper and copper alloys[J]. Copper Engineering,2026(3):67-76.
2.Chongqing Industry Polytechnic University,Chongqing401120,China
Citations
Li Jie,Yang Yang,Wu Ping,Zhu Dehao,Liang Yan,Pu Xinran,Liu Jing,Wen Jiaxin. Research status on anticorrosion coating for copper and copper alloys[J]. Copper Engineering,2026(3):67-76.
Abstract
Copper and copper alloys have remarkable advantages such as strong plasticity, good processing performance, and excellent electrical and thermal conductivity, which are widely used in defense technology, electrical engineering, construction and light industry. Surface coating is an important technology widely used for corrosion protection of copper and copper alloys. Common anti-corrosion coatings used on the surface of copper and copper alloys mainly include non-metallic coatings, metallic coatings, and graphene coatings. In particular, non-metallic coatings include polymer coatings, self-assembled monomolecular films, and sol-gel coatings. Metallic coatings are classified into conventional electroplating coatings, thermal spray coatings, laser cladding layers and so on. In the aspects of application situation, the main corrosion types and protection measurements of copper and copper alloys, this paper summarized research development of the anti-corrosion coatings for copper and copper alloys, and focused on the main components, preparation methods, performance characteristics, and application prospects of various coatings. Meanwhile, this paper illuminated corrosion protection mechanisms of various coatings on copper and copper alloys, pointed out the shortcomings of various coatings, and then provided an outlook for development trends of the anti-corrosion coatings for copper and copper alloys, including four key research directions.
Keywords
copper and copper alloys;corrosion protection;nonmetallic coating;metallic coating;graphene coating;
以纯铜为基体加入一种或几种其他元素所构成的合金称为铜合金。按照纯铜基体中添加元素的种类不同,铜及其合金可以分为纯铜、青铜、黄铜和白铜等4种类型。铜的热力学性质较稳定,电位比较正[0.34 V vs. 标准氢电极(SHE)],金属铜经过化学或电化学反应,表面可形成一层具有防护性能的致密氧化膜,抑制铜基体的腐蚀[ 辛嘉木,范林,刘亚鹏,等. 铜及其合金在海洋环境中的腐蚀机理研究进展 [J]. 装备环境工程,2024,21(10):127-136. 3]。然而,当铜及其合金长期服役于潮湿大气环境中时,其表面会因腐蚀而形成蓝绿色或绿棕色的腐蚀产物——铜绿。铜绿的主要成分是碱式碳酸铜,服役环境中如存在SO2、NO2和Cl−等侵蚀性较强的粒子,还可加剧铜及其合金的腐蚀。
根据腐蚀环境的不同,铜及其合金的腐蚀主要有大气腐蚀、海水腐蚀、土壤腐蚀和化学介质腐蚀等类型。大气腐蚀是金属应用中覆盖面最广、破坏性最大的一种腐蚀形式。绝大多数的铜及其合金材料服役于大气环境中,大气对其产生的腐蚀包含了一系列复杂的物理化学过程,其本质是薄液膜下的化学和电化学反应[ Dante J F,Kelly R G. The evolution of the adsorbed solution layer during atmospheric corrosion and its effects on the corrosion rate of copper [J]. Journal of the Electrochemical Society,1993,140(7):1890-1897. 4]。其次是海水腐蚀。铜及其合金在水环境下广泛使用,其在淡水介质中耐蚀性能优异,但在海水介质中,由于含有大量侵蚀性Cl−,面临的腐蚀问题较为严重[ 李川,罗茜,张薇. 典型舰船用金属材料腐蚀与防护研究进展 [J]. 装备环境工程,2023,20(8):80-89. 5]。
有机高分子涂层由有机高分子涂料涂覆在金属基体表面制备而成。该涂层防护技术基于将金属基体与外界腐蚀介质隔离,以及通过化学钝化或缓蚀机制,实现基体表面腐蚀防护的功能,具有施工方便、适用性强和涂层装饰性好的优势[ 杲广尧,曹凤婷,高雅,等. 金属表面有机防腐涂层研究进展 [J]. 材料研究与应用,2023,17(2):251-264. 10]。近年来,在船舶、装备制造等领域,环氧树脂涂层、氯化橡胶涂层、醇酸树脂涂层等高分子涂层已经广泛应用于铜及其合金的防腐和防污[ 孙宇海漩,贺春林,杨杰,等. 铜合金在海水中的腐蚀与防护研究进展 [J]. 中国材料进展,2023,42(11):874-883. 13],而且这些涂层附着力、防腐性能等方面还有进一步改善和提升的空间。Cheng等[ Cheng Y Y,Wu B,Ma X F,et al. Facile preparation of high density polyethylene superhydrophobic/superoleophilic coatings on glass,copper and polyurethane sponge for self-cleaning,corrosion resistance and efficient oil/water separation [J]. Journal of Colloid and Interface Science,2018,525:76-85. 14]采用高密度聚乙烯树脂通过滴涂法在铜基体表面制备了超疏水涂层,研究发现,聚乙烯涂层不但有效抑制了铜基体的腐蚀过程(其腐蚀电流密度降低至2.867×10−6 A/cm2,如图1所示),而且具有良好的超疏水性能(疏水角150°)及油水分离作用。Kumar等[ Kumar V,Kumar Arya N,Ullas A V,Ji G. Coating of epoxy resin and MMT clay nanocomposite on copper and examination of their corrosion behaviours in NaCl [J]. Materials Today:Proceedings,2023 https://doi.org/10.1016/j.matpr.2023.02.172. 15]在铜基体表面制备了环氧树脂-纳米蒙脱土复合涂层,并在0.5 mol/L NaCl溶液中测试了所制备复合涂层对铜基体的防腐蚀性能,结果显示,该环氧复合涂层对铜基体具有良好的腐蚀防护作用,且当蒙脱土质量分数为5.0%时其防腐蚀效果最好。白雪等[ 白雪,刘希燕,蒋健明. 铜合金管路用防腐涂料的制备 [J]. 上海涂料,2013,51(4):19-21. 16]在海洋船舶上的铜合金管表面制备了环氧树脂防腐涂层,该涂层附着力可达10.2 MPa,耐盐雾时长可达5000 h,50 cm耐冲击试验合格,可为铜合金管路提供良好的腐蚀防护。Liu等[ Liu J,Lu Z H,Zhang L W,et al. Studies of corrosion behaviors of a carbon steel/copper-nickel alloy couple under epoxy coating with artificial defect in 3.5 wt.% NaCl solution using the WBE and EIS techniques [J]. Progress in Organic Coatings,2020,148:105909. 17]先在铜镍合金上涂覆环氧树脂涂层,然后通过丝束电极(wire beam electrode,WBE)和电化学阻抗谱技术研究了环氧涂层在质量分数为3.5%的NaCl溶液中对铜镍合金的腐蚀防护性能。研究结果表明,当环氧涂层铜镍合金作为阴极时,铜合金基材的腐蚀得到了一定程度的抑制,但由于环氧涂层铜镍合金在电偶腐蚀过程中存在电化学不均匀性,导致阴极腐蚀电流出现先增大后趋于平稳的现象。
图1 铜网在NaCl质量分数为3.5%的水溶液中的动电位极化Tafel曲线
Fig. 1 Potentiodynamic polarization Tafel curves of copper mesh in 3.5% NaCl aqueous solution[ Cheng Y Y,Wu B,Ma X F,et al. Facile preparation of high density polyethylene superhydrophobic/superoleophilic coatings on glass,copper and polyurethane sponge for self-cleaning,corrosion resistance and efficient oil/water separation [J]. Journal of Colloid and Interface Science,2018,525:76-85. 14]
采用单一成膜树脂制备的高分子涂层对铜及其合金的防腐效果往往不能满足要求,而通过掺杂纳米材料改性是增强高分子涂层防腐性能的有效手段之一。Bahari等[ Bahari H S,Ye F,Carrillo E A T,et al. Chitosan nanocomposite coatings with enhanced corrosion inhibition effects for copper [J]. International Journal of Biological Macromolecules,2020,162:1566-1577. 18]在铜表面通过自组装的方法制备了壳聚糖涂层,并向涂层中掺杂了2-巯基苯并噻唑(MBT)和纳米SiO2,研究结果表明,壳聚糖涂层铜基体具有良好的防腐性能,且纳米SiO2的加入降低了涂层的溶胀率,提高了涂层的热稳定性和耐蚀性能。
1.2 自组装单分子膜
20世纪80年代以来,作为构建新型超薄有机薄膜的分子自组装技术得到了快速发展。将金属基体浸泡于含活性分子的溶液或其他介质中,有机活性分子可通过化学键自发地吸附在金属基体界面上,形成一层热力学稳定且致密有序的单层分子膜,这层分子膜即自组装单分子膜,其结构如图2所示。单分子膜自组装技术不受金属基体形状的限制,且操作简单,已经被应用于二次电池铜集流体的腐蚀防护、铜及其合金部件的短期保护等领域[ Choi K,Choi H,Min J,et al. A short review on interface engineering of perovskite solar cells:a self-assembled monolayer and its roles [J]. Solar RRL,2020,4(2):1900251. 19]。
图2 自组装单分子膜的结构示意图
Fig. 2 Schematic diagram of self-assembled monomolecular film[ Choi K,Choi H,Min J,et al. A short review on interface engineering of perovskite solar cells:a self-assembled monolayer and its roles [J]. Solar RRL,2020,4(2):1900251. 19]
Fig. 3 (a) Potentiodynamic polarization curves and (b) electrochemical impedance spectra of the bare Cu and copper electrodes modified by non-hydrophobic and super-hydrophobic self-assembled films after immersion in sterile seawater for 1 day[ Liu T,Chen S G,Cheng S,et al. Corrosion behavior of super-hydrophobic surface on copper in seawater [J]. Electrochimica Acta,2007,52(28):8003-8007. 22]
然而,单一成分容易导致有机硅溶胶-凝胶涂层交联致密度低、附着力差,并会导致其对铜及其合金的防腐效果低于其对Al、Mg等金属的防腐效果[ Zheng S X,Li J H. Inorganic-organic sol gel hybrid coatings for corrosion protection of metals [J]. Journal of Sol-Gel Science and Technology,2010,54(2):174-187. 25]。为了提高溶胶-凝胶涂层对铜及其合金的防腐性能,研究人员尝试了多种方法。
Langenfeld等[ Langenfeld S, Jonschker G, Schmidt H. Neue sol-gel-beschichtungen als korrosions-und verschleißschutz Für NE-metalle [J]. Materialwissenschaft und Werkstofftechnik, 1998, 29(1): 23-29. 26]先以3-缩水甘油基氧丙基三甲氧基硅烷为原料制备了硅溶胶溶液,再在纯铜基体表面制备了一种有机硅溶胶-凝胶涂层,并研究了该涂层对铜基体的腐蚀防护性能。沈路力等[ 沈路力,彭叔森,王刚,等. 巯基有机硅溶胶-凝胶涂层对铜合金H90的腐蚀防护性能研究 [J]. 表面技术,2018,47(10):30-36. 27]以乙酸为催化剂制备了四乙氧基硅烷与γ-巯丙基三甲氧基硅烷混合溶胶溶液,并在铜合金H90表面制备了一种复合溶胶-凝胶涂层。经测试,该涂层的硬度不低于5H,附着力为0级,自腐蚀电流密度低至1.16×10−8 A/cm2,耐盐雾时长可超720 h。Karthik等[ Karthik N,Sethuraman M G. Improved copper corrosion resistance of epoxy-functionalized hybrid sol-gel monolayers by thiosemicarbazide [J]. Ionics,2015,21(5):1477-1488. 28]以3-(2,3-环氧丙氧基)丙基三甲氧基硅烷(KH560)、四乙氧基硅烷和氨基硫脲为前驱体制备了混合溶胶-凝胶涂层,制备原理如图4所示。结果表明,混合溶胶-凝胶涂层对铜基体的防腐性能优异,特别是氨基硫脲的加入可明显改善涂层的腐蚀防护性能,这主要是因为多种含硫基团前驱体的协同作用促进了有机硅溶胶-凝胶涂层对铜合金腐蚀防护性能的提高。
图4 铜表面混合溶胶-凝胶单分子层自组装原理
Fig. 4 Self-assembly of the mixed sol-gel monolayers onto copper surface[ Karthik N,Sethuraman M G. Improved copper corrosion resistance of epoxy-functionalized hybrid sol-gel monolayers by thiosemicarbazide [J]. Ionics,2015,21(5):1477-1488. 28]
热喷涂技术是一种表面工程技术。其原理是:利用各种不同的热源,将欲喷涂的各种材料(如金属、合金、陶瓷、塑料及其各类复合材料)的丝材或粉末加热至熔化状态,然后通过高速气流将其雾化成微粒并喷射到经过预处理的基材表面,待冷却固化后形成连续涂层。该技术具有工艺简单、生产效率高、涂层厚度可控、适合大规模工业化生产等优点[ Tekmen C,Ozdemir I,Fritsche G,et al. Structural evolution of mechanically alloyed Al-12Si/TiB2/h-BN composite powder coating by atmospheric plasma spraying [J]. Surface and Coatings Technology,2009,203(14):2046-2051. 33]。铜及其合金的热喷涂技术已发展出多种类型的工艺方法,其中应用较为广泛、技术较为成熟的是火焰喷涂技术和等离子喷涂技术。Xi等[ Xi H H,He P F,Wang H D,et al. Microstructure and mechanical properties of Mo coating deposited by supersonic plasma spraying [J]. International Journal of Refractory Metals and Hard Materials,2020,86:105095. 34]借助超声等离子喷涂技术在铜基体表面制备了Mo涂层。 该Mo涂层的相组成为纯Mo,且涂层的氧化程度极低,结构致密,如图5所示。与铜基体表面相比,涂层表面硬度提高64.3%,弹性模量提高70.0%,磨损试验中材料损失量降低43.5%,涂层表现出良好的耐磨损能力。
Fig. 5 (a) Cross-section image of Mo coating;(b) Enlarged view of area A in (a);(c) EDS analysis of area A; (d) XRD spectrum of Mo coating[ Xi H H,He P F,Wang H D,et al. Microstructure and mechanical properties of Mo coating deposited by supersonic plasma spraying [J]. International Journal of Refractory Metals and Hard Materials,2020,86:105095. 34]
Fig. 6 Morphology of the junction between the Cu-W-Ni alloy cladding layer and substrate:(a) CuW10Ni3;(b) CuW20Ni3;(c) CuW40Ni3[ 薛守洪,李保坤,叶海龙,等. 纯铜触头表面激光熔覆铜基合金的性能试验研究 [J]. 电工材料,2024(1):19-25. 40]
近年来,石墨烯涂层作为铜及其合金表面防腐涂层的研究已初见成效。早期,Chen等[ Chen S S,Brown L,Levendorf M,et al. Oxidation resistance of graphene-coated Cu and Cu/Ni alloy [J]. ACS Nano,2011,5(2):1321-1327. 43]采用CVD法在铜及其合金表面制备出一种石墨烯防腐涂层,该涂层能够有效抑制基材在大气中氧化以及在H2O2溶液中的腐蚀过程。如图7所示,Kirkland等[ Kirkland N T,Schiller T,Medhekar N,et al. Exploring graphene as a corrosion protection barrier [J]. Corrosion Science,2012,56:1-4. 44]为防止纯Cu在NaCl溶液中的腐蚀问题,采用CVD法在纯Cu表面制备出石墨烯涂层,该涂层可通过抑制Cu基体的阴极还原反应来有效阻止腐蚀介质对铜基体的腐蚀,且纯Cu表面石墨烯大部分以单层形式存在,只有少数为多层形式。
图7 铜基体表面石墨烯涂层的(a)光学显微镜照片及(b)不同区域的拉曼光谱图
Fig. 7 (a) Optical microscopy image and (b) Raman spectra of indicated areas for graphene-coated copper[ Kirkland N T,Schiller T,Medhekar N,et al. Exploring graphene as a corrosion protection barrier [J]. Corrosion Science,2012,56:1-4. 44]
然而,最新研究发现,在某些情况下,存在石墨烯涂层促进铜合金表面腐蚀的现象。
Migkovic-Stankovic等[ Mišković-Stanković V,Jevremović I,Jung I,et al. Electrochemical study of corrosion behavior of graphene coatings on copper and aluminum in a chloride solution [J]. Carbon,2014,75:335-344. 45]通过电化学方法研究了多层石墨烯涂层在NaCl溶液中对铜基体腐蚀防护的稳定性和可靠性。结果显示,对于铜基体,这类涂层抑制腐蚀的持续时间有限,约10个月后,防护效果逐渐减弱甚至失效,铜基体会重新出现腐蚀现象,且腐蚀程度甚至超过无涂层铜基体。这是因为石墨烯涂层的高导电性对铜表面的电化学腐蚀具有促进作用,其腐蚀产物主要为铜的氧化物,且腐蚀应力可导致涂层产生裂纹,从而造成新的腐蚀,新的腐蚀甚至比无涂层铜基体更严重。
DanteJ F,KellyR G. The evolution of the adsorbed solution layer during atmospheric corrosion and its effects on the corrosion rate of copper [J]. Journal of the Electrochemical Society,1993,140(7):1890-1897.
ChengY Y,WuB,MaX F,et al. Facile preparation of high density polyethylene superhydrophobic/superoleophilic coatings on glass,copper and polyurethane sponge for self-cleaning,corrosion resistance and efficient oil/water separation [J]. Journal of Colloid and Interface Science,2018,525:76-85.
[15]
KumarV,Kumar AryaN,UllasA V,JiG. Coating of epoxy resin and MMT clay nanocomposite on copper and examination of their corrosion behaviours in NaCl [J]. Materials Today:Proceedings,2023https://doi.org/10.1016/j.matpr.2023.02.172.
LiuJ,LuZ H,ZhangL W,et al. Studies of corrosion behaviors of a carbon steel/copper-nickel alloy couple under epoxy coating with artificial defect in 3.5 wt.% NaCl solution using the WBE and EIS techniques [J]. Progress in Organic Coatings,2020,148:105909.
[18]
BahariH S,YeF,CarrilloE A T,et al. Chitosan nanocomposite coatings with enhanced corrosion inhibition effects for copper [J]. International Journal of Biological Macromolecules,2020,162:1566-1577.
[19]
ChoiK,ChoiH,MinJ,et al. A short review on interface engineering of perovskite solar cells:a self-assembled monolayer and its roles [J]. Solar RRL,2020,4(2):1900251.
ZhengS X,LiJ H. Inorganic-organic sol gel hybrid coatings for corrosion protection of metals [J]. Journal of Sol-Gel Science and Technology,2010,54(2):174-187.
[26]
LangenfeldS, JonschkerG, SchmidtH. Neue sol-gel-beschichtungen als korrosions-und verschleißschutz Für NE-metalle [J]. Materialwissenschaft und Werkstofftechnik, 1998, 29(1): 23-29.
KarthikN,SethuramanM G. Improved copper corrosion resistance of epoxy-functionalized hybrid sol-gel monolayers by thiosemicarbazide [J]. Ionics,2015,21(5):1477-1488.
TekmenC,OzdemirI,FritscheG,et al. Structural evolution of mechanically alloyed Al-12Si/TiB2/h-BN composite powder coating by atmospheric plasma spraying [J]. Surface and Coatings Technology,2009,203(14):2046-2051.
[34]
XiH H,HeP F,WangH D,et al. Microstructure and mechanical properties of Mo coating deposited by supersonic plasma spraying [J]. International Journal of Refractory Metals and Hard Materials,2020,86:105095.
ChenS S,BrownL,LevendorfM,et al. Oxidation resistance of graphene-coated Cu and Cu/Ni alloy [J]. ACS Nano,2011,5(2):1321-1327.
[44]
KirklandN T,SchillerT,MedhekarN,et al. Exploring graphene as a corrosion protection barrier [J]. Corrosion Science,2012,56:1-4.
[45]
Mišković-StankovićV,JevremovićI,JungI,et al. Electrochemical study of corrosion behavior of graphene coatings on copper and aluminum in a chloride solution [J]. Carbon,2014,75:335-344.