Corrosion resistance and hydrophobicity of myristic acid modified Mg--Al LDH/Mg(OH)₂ steam coating on magnesium alloy AZ31

Abstract

A hydrophobic surface was successfully fabricated on the Mg–Al-layered double hydroxide (Mg–Al LDH)/Mg(OH)₂-coated AZ31 magnesium alloy via an in-situ steam coating (SC) process and a subsequent surface modification with environment-friendly myristic acid (MA). The microstructure, composition and hydrophobicity of SC/MA composite coating were investigated by XRD, SEM, EDS, FTIR, and contact angle (CA) measurement. The corrosion behavior of the hybrid coating was evaluated by potentiodynamic polarization, EIS and hydrogen evolution test in 3.5 wt.% NaCl solution. The results showed that the LDH coating had nano-flake microstructure, which remained unchanged after modification with MA. The CA of the MA-modified coating surface reached up to 129°±3.5°, and the corrosion current density of SC/MA-2 coating decreased about three orders of the magnitude compared to that of the substrate. It is proven that the modified surface has an effective anti-corrosion effect on AZ31 alloy. The formation mechanism and the corrosion mechanism of the coating were also discussed.

Keywords

magnesium alloy / steam coating / layered double hydroxide / corrosion resistance / hydrophobicity

References

[1] Jia P, Wu M, Zhang J, . Effects of Mg‒Zn‒Y quasicrystal addition on the microstructures, mechanical performances and corrosion behaviors of as-cast AM60 magnesium alloy. Materials Research Express, 2018, 5(10): 106512 doi:10.1088/2053-1591/aada70

[2] Pan F S, Zeng B, Jiang B, . Enhanced mechanical properties of AZ31B magnesium alloy thin sheets processed by on-line heating rolling. Journal of Alloys and Compounds, 2017, 693: 414–420

[3] Li F, Liu Y, Li X B. Dynamic recrystallization behavior of AZ31 magnesium alloy processed by alternate forward extrusion. Frontiers of Materials Science, 2017, 11(3): 296–305

[4] Jin T, Wang Y, Yin H, . Corrosion protection properties and mechanism of epoxy/acetic acid-doped polyaniline coating on magnesium alloy. Journal of Nanoscience and Nanotechnology, 2018, 18(7): 4992–5000

[5] Jin H, Yang X, Wang M. Chemical conversion coating on AZ31B magnesium alloy and its corrosion tendency. Acta Metallurgica Sinica (English Letters), 2009, 22(1): 65–70

[6] Ishizaki T, Kudo R, Omi T, . Magnesium hydroxide/magnesium phosphate compounds composite coating for corrosion protection of magnesium alloy by a combination process of chemical conversion and steam curing. Materials Letters, 2012, 68: 122–125

[7] Zhang F, Zhang C L, Song L, . Corrosion resistance of superhydrophobic Mg‒Al layered double hydroxide coatings on aluminum alloys. Acta Metallurgica Sinica (English Letters), 2015, 28(11): 1373–1381 doi:10.1007/s40195-015-0335-4

[8] Li C Y, Fan X L, Zeng R C, . Corrosion resistance of in-situ growth of nano-sized Mg(OH)₂ on micro-arc oxidized magnesium alloy AZ31 — Influence of EDTA. Journal of Materials Science and Technology, 2019, 35(6): 1088–1098

[9] Singh B P, Jena B K, Bhattacharjee S, . Development of oxidation and corrosion resistance hydrophobic graphene oxide‒polymer composite coating on copper. Surface and Coatings Technology, 2013, 232: 475–481

[10] Zeng R C, Qi W C, Song Y W, . In vitro degradation of MAO/PLA coating on Mg‒1.21Li‒1.12Ca‒1.0Y alloy. Frontiers of Materials Science, 2014, 8(4): 343–353

[11] Jin T, Han Y, Bai R, . Corrosion protection properties of nano NH₂-reduced graphene oxide/epoxy composite coatings formed by self-curing on magnesium alloy. Journal of Nanoscience and Nanotechnology, 2018, 18(7): 4971–4981

[12] Liang J, Zhang R H, Peng Z J, . One-step electrochemical fabrication of bilayered MgO/polymer coating on magnesium alloy. Frontiers of Materials Science, 2014, 8(3): 307–312

[13] Jin T, Kong F M, Bai R Q, . Anti-corrosion mechanism of epoxy-resin and different content Fe₂O₃ coatings on magnesium alloy. Frontiers of Materials Science, 2016, 10(4): 367–374

[14] Li L Y, Cui L Y, Zeng R C, . Advances in functionalized polymer coatings on biodegradable magnesium alloys — A review. Acta Biomaterialia, 2018, 79: 23–36

[15] Zhang G, Wu L, Tang A T, . Growth behavior of MgAl-layered double hydroxide films by conversion of anodic films on magnesium alloy AZ31 and their corrosion protection. Applied Surface Science, 2018, 456: 419–429

[16] Wu L, Yang D N, Zhang G, . Fabrication and characterization of Mg‒M layered double hydroxide films on anodized magnesium alloy AZ31. Applied Surface Science, 2018, 431: 177–186

[17] Zhang G, Wu L, Tang A T, . Active corrosion protection by a smart coating based on a MgAl-layered double hydroxide on a cerium-modified plasma electrolytic oxidation coating on Mg alloy AZ31. Corrosion Science, 2018, 139: 370–382

[18] Ishizaki T, Kamiyama N, Watanabe K, . Corrosion resistance of Mg(OH)₂/Mg‒Al layered double hydroxide composite film formed directly on combustion-resistant magnesium alloy AMCa602 by steam coating. Corrosion Science, 2015, 92: 76–84

[19] Guo L, Zhang F, Lu J C, . A comparison of corrosion inhibition of magnesium aluminum and zinc aluminum vanadate intercalated layered double hydroxides on magnesium alloys. Frontiers of Materials Science, 2018, 12(2): 198–206

[20] Chen J, Song Y W, Shan D Y, . Study of the in situ growth mechanism of Mg‒Al hydrotalcite conversion film on AZ31 magnesium alloy. Corrosion Science, 2012, 63: 148–158

[21] Chen J, Song Y, Shan D, . Study of the corrosion mechanism of the in situ grown Mg–Al–CO₃²⁻ hydrotalcite film on AZ31 alloy. Corrosion Science, 2012, 65: 268–277

[22] Zeng R C, Li X T, Liu Z G, . Corrosion resistance of Zn‒Al layered double hydroxide/poly(lactic acid) composite coating on magnesium alloy AZ31. Frontiers of Materials Science, 2015, 9(4): 355–365

[23] Li D D, Wang F Y, Yu X, . Anticorrosion organic coating with layered double hydroxide loaded with corrosion inhibitor of tungstate. Progress in Organic Coatings, 2011, 71(3): 302–309

[24] Zeng R C, Liu Z G, Zhang F, . Corrosion of molybdate intercalated hydrotalcite coating on AZ31 Mg alloy. Journal of Materials Chemistry A: Materials for Energy and Sustainability, 2014, 2(32): 13049–13057

[25] Yao Q S, Zhang F, Song L, . Corrosion resistance of a ceria/polymethyltrimethoxysilane modified Mg‒Al-layered double hydroxide on AZ31 magnesium alloy. Journal of Alloys and Compounds, 2018, 764: 913–928

[26] Kamiyama N, Panomsuwan G, Yamamoto E, . Effect of treatment time in the Mg(OH)₂/Mg‒Al LDH composite film formed on Mg alloy AZ31 by steam coating on the corrosion resistance. Surface and Coatings Technology, 2016, 286: 172–177

[27] Ishizaki T, Chiba S, Suzuki H. In situ formation of anticorrosive Mg‒Al layered double hydroxide-containing magnesium hydroxide film on magnesium alloy by steam coating. ECS Electrochemistry Letters, 2013, 2(5): C15–C17

[28] Ishizaki T, Chiba S, Watanabe K, . Corrosion resistance of Mg‒Al layered double hydroxide container-containing magnesium hydroxide films formed directly on magnesium alloy by chemical-free steam coating. Journal of Materials Chemistry A: Materials for Energy and Sustainability, 2013, 1(31): 8968–8977

[29] Huang S, Peng H, Tjiu W W, . Assembling exfoliated layered double hydroxide (LDH) nanosheet/carbon nanotube (CNT) hybrids via electrostatic force and fabricating nylon nanocomposites. The Journal of Physical Chemistry B, 2010, 114(50): 16766–16772

[30] Liao H, Jia Y, Wang L, . Size effect of layered double hydroxide platelets on the crystallization behavior of isotactic polypropylene. ACS Omega, 2017, 2(8): 4253–4260

[31] Zhang J, Gu C, Tu J. Robust slippery coating with superior corrosion resistance and anti-icing performance for AZ31B Mg alloy protection. ACS Applied Materials & Interfaces, 2017, 9(12): 11247–11257

[32] Yuan Z, Wang X, Bin J, . Controllable fabrication of lotus-leaf-like superhydrophobic surface on copper foil by self-assembly. Applied Physics A: Materials Science & Processing, 2014, 116(4): 1613‒1620 doi:10.1007/s00339-014-8472-6

[33] Richard E, Aruna S T, Basu B J. Superhydrophobic surfaces fabricated by surface modification of alumina particles. Applied Surface Science, 2012, 258(24): 10199–10204

[34] Cao N, Miao Y Y, Zhang D L, . Preparation of mussel-inspired perfluorinated polydopamine film on brass substrates: Superhydrophobic and anti-corrosion application. Progress in Organic Coatings, 2018, 125: 109–118

[35] Kuang J, Ba Z, Li Z, . Fabrication of a superhydrophobic Mg‒Mn layered double hydroxides coating on pure magnesium and its corrosion resistance. Surface and Coatings Technology, 2019, 361: 75–82

[36] Zhang G, Tang A T, Wu L, . In-situ grown super- or hydrophobic Mg‒Al layered double hydroxides films on the anodized magnesium alloy to improve corrosion properties. Surface and Coatings Technology, 2019, 366: 238–247

[37] Zhao L, Liu Q, Gao R, . One-step method for the fabrication of superhydrophobic surface on magnesium alloy and its corrosion protection, antifouling performance. Corrosion Science, 2014, 80: 177–183

[38] Ding P, Li Z Z, Wang Q, . In situ growth of layered double hydroxide films under dynamic processes: Influence of metal cations. Materials Letters, 2012, 77: 1–3

[39] Ozturk S, Balkose D, Okur S, . Effect of humidity on electrical conductivity of zinc stearate nanofilms. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2007, 302(1‒3): 67–74

[40] Wang Y H, Wang W, Zhong L, . Super-hydrophobic surface on pure magnesium substrate by wet chemical method. Applied Surface Science, 2010, 256(12): 3837–3840

[41] Xi J, Feng L, Jiang L. A general approach for fabrication of superhydrophobic and superamphiphobic surfaces. Applied Physics Letters, 2008, 92(5): 053102

[42] Zhang F, Liu Z G, Zeng R C, . Corrosion resistance of Mg‒Al-LDH coating on magnesium alloy AZ31. Surface and Coatings Technology, 2014, 258: 1152–1158

[43] Zhang F, Zhang C L, Zeng R C, . Corrosion resistance of the superhydrophobic Mg(OH)₂/Mg‒Al layered double hydroxide coatings on magnesium alloys. Metals, 2016, 6(4): 85

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature