Preparation and property of self-sealed plasma electrolytic oxide coating on magnesium alloy

Abstract

Plasma electrochemical oxidation (PEO) is a surface modification technology to form ceramic coatings on magnesium alloys. However, its application is limited due to its defects. This work reports a novel preparation of in-situ sealing of PEO coatings by four-layer voltage and sol addition. The morphology and structure were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffractometer (XRD). Image-Pro Plus 6.0 was used to determine the porosity of the coating, which was decreased from 8.53% to 0.51%. Simultaneously, the coating thickness was increased by a factor of four. The anti-corrosion performance of each sample was evaluated using electrochemical tests, and the findings revealed that the corrosion current density of coatings (i _corr) of the samples were lowered from 9.152 × 10⁻² to 6.152 × 10−⁴ mA·cm−², and the total resistance (R _T) of the samples were enhanced from 2.19 × 10⁴ to 2.33 × 10⁵ Ω·cm². The salt spray test used to simulate the actual environment showed that corrosion points appeared on the surface of the coating only at the 336 h. In addition, the mechanism of PEO self-sealing behavior was described in this article.

Keywords

magnesium alloy / in-situ sealing / plasma electrolytic oxidation / corrosion resistance

References

[1] Yang Y, Xiong XM, Chen J, Peng XD, Chen DL, Pan FS. Research advances in magnesium and magnesium alloys worldwide in 2020. J. Magnes. Alloys, 2021, 9(3): 705.

[2] Luo K, Zhang L, Wu GH, Liu WC, Ding WJ. Effect of Y and Gd content on the microstructure and mechanical properties of Mg—Y—RE alloys. J. Magnes. Alloys, 2019, 7(2): 345.

[3] Huang HL, Yang WL. Corrosion behavior of AZ91D magnesium alloy in distilled water. Arab. J. Chem., 2020, 13(7): 6044.

[4] Kang GZ, Li H. Review on cyclic plasticity of magnesium alloys: Experiments and constitutive models. Int. J. Miner. Metall. Mater., 2021, 28(4): 567.

[5] Samadpour F, Faraji G, Siahsarani A. Processing of AM60 magnesium alloy by hydrostatic cyclic expansion extrusion at elevated temperature as a new severe plastic deformation method. Int. J. Miner. Metall. Mater., 2020, 27(5): 669.

[6] Chu JH, Tong LB, Wen M, et al. Inhibited corrosion activity of biomimetic graphene-based coating on Mg alloy through a cerium intermediate layer. Carbon, 2020, 161, 577.

[7] L.X. Li, Z.H. Xie, C. Fernandez, et al., Development of a thiophene derivative modified LDH coating for Mg alloy corrosion protection, Electrochim. Acta, 330(2020), art. No. 135186.

[8] Duan GQ, Yang LX, Liao SJ, et al. Designing for the chemical conversion coating with high corrosion resistance and low electrical contact resistance on AZ91D magnesium alloy. Corros. Sci., 2018, 135, 197.

[9] Bayrak Ghahramanzadeh Asl H, Ak A. Protein adsorption, cell viability and corrosion properties of Ti₆Al₄V alloy treated by plasma oxidation and anodic oxidation. Int. J. Miner. Metall. Mater., 2020, 27(9): 1269.

[10] Zhang ZQ, Wang L, Zeng MQ, et al. Corrosion resistance and superhydrophobicity of one-step polypropylene coating on anodized AZ31 Mg alloy. J. Magnes. Alloys, 2021, 9(4): 1443.

[11] Jiang D, Zhou H, Wan S, Cai GY, Dong ZH. Fabrication of superhydrophobic coating on magnesium alloy with improved corrosion resistance by combining micro-arc oxidation and cyclic assembly. Surf. Coat. Technol., 2018, 339, 155.

[12] Zhao YB, Shi LQ, Ji XJ, et al. Corrosion resistance and antibacterial properties of polysiloxane modified layer-by-layer assembled self-healing coating on magnesium alloy. J. Colloid Interface Sci., 2018, 526, 43.

[13] Ashassi-Sorkhabi H, Moradi-Alavian S, Jafari R, Kazempour A, Asghari E. Effect of amino acids and montmorillonite nanoparticles on improving the corrosion protection characteristics of hybrid sol—gel coating applied on AZ91 Mg alloy. Mater. Chem. Phys., 2019, 225, 298.

[14] Lu TX, Chen CG, Guo ZM, Li P, Guo MX. Tungsten nanoparticle-strengthened copper composite prepared by a solgel method and in situ reaction. Int. J. Miner. Metall. Mater., 2019, 26(11): 1477.

[15] Dehnavi V, Binns WJ, Noël JJ, Shoesmith DW, Luan BL. Growth behaviour of low-energy plasma electrolytic oxidation coatings on a magnesium alloy. J. Magnes. Alloys, 2018, 6(3): 229.

[16] Roknian M, Fattah-Alhosseini A, Gashti SO, Keshavarz MK. Study of the effect of ZnO nanoparticles addition to PEO coatings on pure titanium substrate: Microstructural analysis, antibacterial effect and corrosion behavior of coatings in Ringer’s physiological solution. J. Alloys Compd., 2018, 740, 330.

[17] Lu XP, Blawert C, Kainer KU, Zheludkevich ML. Investigation of the formation mechanisms of plasma electrolytic oxidation coatings on Mg alloy AM50 using particles. Electrochim. Acta, 2016, 196, 680.

[18] Tang H, Gao Y. Preparation and characterization of hydroxyapatite containing coating on AZ31 magnesium alloy by micro-arc oxidation. J. Alloys Compd., 2016, 688, 699.

[19] Mashtalyar DV, Gnedenkov SV, Sinebryukhov SL, Imshinetskiy IM, Puz’ AV. Plasma electrolytic oxidation of the magnesium alloy MA8 in electrolytes containing TiN nanoparticles. J. Mater. Sci. Technol., 2017, 33(5): 461.

[20] Wu KR, Hung CH, Yeh CW, Wu JK. Microporous TiO₂—WO₃/TiO₂ films with visible-light photocatalytic activity synthesized by micro arc oxidation and DC magnetron sputtering. Appl. Surf. Sci., 2012, 263, 688.

[21] Muhaffel F, Cimenoglu H. Development of corrosion and wear resistant micro-arc oxidation coating on a magnesium alloy. Surf. Coat. Technol., 2019, 357, 822.

[22] A. Fattah-Alhosseini, K. Babaei, and M. Molaei, Plasma electrolytic oxidation (PEO) treatment of zinc and its alloys: A review, Surf. Interfaces, 18(2020), art. No. 100441.

[23] Zhu BW, Wang L, Wu YZ, Yue W, Liang J, Cao BC. Improving corrosion resistance and biocompatibility of AZ31 magnesium alloy by ultrasonic cold forging and micro-arc oxidation. J. Biomater. Appl., 2022, 36(9): 1664.

[24] Babaei M, Dehghanian C, Taheri P, Babaei M. Effect of duty cycle and electrolyte additive on photocatalytic performance of TiO₂—ZrO₂ composite layers prepared on CP Ti by micro arc oxidation method. Surf. Coat. Technol., 2016, 307, 554.

[25] Joni M S, Fattah-Alhosseini A. Effect of KOH concentration on the electrochemical behavior of coatings formed by pulsed DC micro-arc oxidation (MAO) on AZ31B Mg alloy. J. Alloys Compd., 2016, 661, 237.

[26] Vakili-Azghandi M, Fattah-Alhosseini A. Effects of duty cycle, current frequency, and current density on corrosion behavior of the plasma electrolytic oxidation coatings on 6061Al alloy in artificial seawater. Metall. Mater. Trans. A, 2017, 48(10): 4681.

[27] Bai LJ, Dong BX, Chen GT, Xin T, Wu JN, Sun XD. Effect of positive pulse voltage on color value and corrosion property of magnesium alloy black micro-arc oxidation ceramic coating. Surf. Coat. Technol., 2019, 374, 402.

[28] Song YW, Dong KH, Shan DY, Han EH. Investigation of a novel self-sealing pore micro-arc oxidation film on AM60 magnesium alloy. J. Magnes. Alloys, 2013, 1(1): 82.

[29] Li Z, Chen Z, Feng S, Zhao T, Wang WZ. Effects of Na₂WO₄ on the MAO coatings on AZ80. Surf. Eng., 2020, 36, 817.

[30] Zou B, Lü GH, Zhang GL, Tian YY. Effect of current frequency on properties of coating formed by microarc oxidation on AZ91D magnesium alloy. Trans. Nonferrous Met. Soc. China, 2015, 25(5): 1500.

[31] Cui XJ, Liu CH, Yang RS, Li MT, Lin XZ. Self-sealing micro-arc oxidation coating on AZ91D Mg alloy and its formation mechanism. Surf. Coat. Technol., 2015, 269, 228.

[32] Pak SN, Yao ZP, Ju KS, Ri CN, Xia QX. Effect of organic additives on structure and corrosion resistance of MAO coating. Vacuum, 2018, 151, 8.

[33] Nadimi M, Dehghanian C. Incorporation of ZnO—ZrO₂ nanoparticles into TiO₂ coatings obtained by PEO on Ti—6Al—4V substrate and evaluation of its corrosion behavior, microstructural and antibacterial effects exposed to SBF solution. Ceram. Int., 2021, 47(23): 33413.

[34] Krishtal MM, Ivashin PV, Yasnikov IS, Polunin AV. Effect of nanosize SiO₂ particles added into electrolyte on the composition and morphology of oxide layers formed in alloy AK6M2 under microarc oxidizing. Met. Sci. Heat Treat., 2015, 57(7–8): 428.

[35] Li WP, Tang MQ, Zhu LQ, Liu HC. Formation of microarc oxidation coatings on magnesium alloy with photocatalytic performance. Appl. Surf. Sci., 2012, 258(24): 10017.

[36] Shi ZM, Liu M, Atrens A. Measurement of the corrosion rate of magnesium alloys using Tafel extrapolation. Corros. Sci., 2010, 52(2): 579.

[37] He MF, Liu L, Wu YT, Tang ZX, Hu WB. Corrosion properties of surface-modified AZ91D magnesium alloy. Corros. Sci., 2008, 50(12): 3267.

[38] Xiang TF, Zheng SL, Zhang M, Sadig HR, Li C. Bioinspired slippery zinc phosphate coating for sustainable corrosion protection. ACS Sustainable Chem. Eng., 2018, 6(8): 10960.

[39] Ramezanzadeh M, Ramezanzadeh B, Mahdavian M, Bahlakeh G. Development of metal-organic framework (MOF) decorated graphene oxide nanoplatforms for anti-corrosion epoxy coatings. Carbon, 2020, 161, 231.

[40] Behera AK, Das A, Das S, Mallik A. Electrochemically functionalized graphene as an anti-corrosion reinforcement in Cu matrix composite thin films. Int. J. Miner. Metall. Mater., 2021, 28(9): 1525.

[41] Shang W, Wu F, Wen YQ, He CB, Zhan XQ, Li YQ. Corrosion resistance and mechanism of graphene oxide composite coatings on magnesium alloy. Ind. Eng. Chem. Res., 2019, 58(3): 1200.

[42] Wu CQ, Liu Q, Chen RR, et al. Fabrication of ZIF-8@SiO₂ micro/nano hierarchical superhydrophobic surface on AZ31 magnesium alloy with impressive corrosion resistance and abrasion resistance. ACS Appl. Mater. Interfaces, 2017, 9(12): 11106.

[43] Fattah-Alhosseini A, Chaharmahali R, Babaei K. Effect of particles addition to solution of plasma electrolytic oxidation (PEO) on the properties of PEO coatings formed on magnesium and its alloys: A review. J. Magnes. Alloys, 2020, 8(3): 799.

[44] Bordbar-Khiabani A, Yarmand B, Mozafari M. Enhanced corrosion resistance and in-vitro biodegradation of plasma electrolytic oxidation coatings prepared on AZ91 Mg alloy using ZnO nanoparticles-incorporated electrolyte. Surf. Coat. Technol., 2019, 360, 153.

[45] Duan HP, Yan CW, Wang FH. Growth process of plasma electrolytic oxidation films formed on magnesium alloy AZ91D in silicate solution. Electrochim. Acta, 2007, 52(15): 5002.

[46] Z.R. Zheng, M.C. Zhao, L.L. Tan, et al., Corrosion behavior of a self-sealing coating containing CeO₂ particles on pure Mg produced by micro-arc oxidation, Surf. Coat. Technol., 386(2020), art. No. 125456.