Mg(OH)2 Film on Micro-arc Oxidation Ceramic Coating of AZ31 Magnesium Alloy: Preparation and Corrosion Resistance

doi:10.15541/jim20190426

Abstract

Abstract:

The micro-arc oxidation (MAO) ceramic coating on AZ31 magnesium alloy was treated by hydrothermal treatment in NaOH solution to study the effect of the concentration of NaOH solution on the microstructure and corrosion resistance of the obtained Mg(OH)₂/MAO composite coating, the formation mechanism and the corrosion mechanism of the hydrothermal film was annalysed at the same time. The results showed that MgO in the surface of MAO ceramic layer was partially dissolved during hydrothermal reaction. And the released Mg ²⁺ was combined with OH ^- in hydrothermal solution to form Mg(OH)₂ nanosheets which deposited on the surface of ceramic layer and inner wall of the pores. With increasing of NaOH concentration of the hydrothermal solution, more Mg(OH)₂ formed during hydrothermal reaction and sealed the inherent defects such as pores and cracks in the MAO ceramic layer, which improved the compactness of the coating. In addition, the electrochemical test results demonstrated that the Mg(OH)₂/MAO composite coating prepared by MAO and hydrothermal treatment achieved better corrosion resistance than the single MAO ceramic layer, and the corrosion resistance of Mg(OH)₂/MAO composite coating increased with the increasing concentration of the hydrothermal solution. And the immersion test showed that Mg(OH)₂/MAO composite coating could provide long-term corrosion protection for magnesium alloy.

Key words: magnesium alloy, micro-arc oxidation, hydrothermal treatment, composite coating, corrosion resistance

CLC Number:

TG174
TG179

WANG Zhihu,ZHANG Jumei,BAI Lijing,ZHANG Guojun. Mg(OH)₂ Film on Micro-arc Oxidation Ceramic Coating of AZ31 Magnesium Alloy: Preparation and Corrosion Resistance[J]. Journal of Inorganic Materials, 2020, 35(6): 709-716.

Figures/Tables 10

Fig. 1 XRD patterns of AZ31 substrate, MAO coating and HT/MAO composite coating

Fig. 2 Surface morphologies of MAO coating and HT/MAO composite coating (a) MAO; (b) HT-0/MAO; (c) HT-0.2/MAO; (d) HT-0.5/MAO; (e) HT-2.0/MAO; (f) HT-2.0/MAO in high magnification

Fig. 3 EDS spectra and element contents of (a) MAO and (b) HT-2.0/MAO

Fig. 4 Static contact angles of MAO coating and HT/MAO composite coating (a)MAO; (b) HT-0/MAO; (c)HT-0.2/MAO; (d)HT-0.5/MAO; (e)HT-2.0/MAO

Fig. 5 Potentiodynamic polarization curves of AZ31 substrate, MAO, HT-0.2/MAO and HT-2.0/MAO

Table 1 Fitting parameters derived from the potentiodynamic polarization curves

Samples	E_corr/V	I_corr/(μA·cm^-2)	β_a/V	β_c/V	R_P/(kΩ·cm²)	C_R/(mm·a^-1)
Bare AZ31	-1.460	22.34	0.284	0.395	3.211	510.5×10^-3
MAO	-1.383	0.0530	1.340	0.209	1.481×10³	1.211×10^-3
HT-0.2/MAO	-1.376	0.0345	0.938	0.409	3.585×10³	0.788×10^-3
HT-2.0/MAO	-1.350	0.0187	1.226	0.208	4.129×10³	0.427×10^-3

Fig. 6 Nyquist and Bode plots of bare AZ31 and coated samples as well as equivalent circuit (a) Nyquist plots of bare AZ31; (b) Nyquist plots of coated samples; (c) Bode plots of all samples; (d-e) physical model and equivalent circuit for coated samples

Fig. 7 Rout, Rinn and Rtotal values of three coatings

Fig. 8 XRD patterns of MAO and HT-0.2/MAO before and after immersion in 3.5wt% NaCl solution

Fig. 9 Surface morphologies of MAO and HT-0.2 /MAO after immersion in 3.5wt% NaCl solution for 14 d (a-b) MAO; (c-d) HT-0.2/MAO

References 29

[1]	SANKARE NARAYANAN T S N, PARK Il S, LEE M H . Strategies to improve the corrosion resistance of microarc oxidation (MAO) coated magnesium alloys for degradable implants: prospects and challenges. Prog. Mater. Sci., 2014,60:1-71. DOI URL
[2]	ZHAO J M, XIE X, ZHANG C . Effect of the graphene oxide additive on the corrosion resistance of the plasma electrolytic oxidation coating of the AZ31 magnesium alloy. Corros. Sci., 2017,114:146-155. DOI URL
[3]	ZHU Y Y, ZHANG S F, ZHAO R F , et al. Influences of Na₂SiO₃ and EDTA-ZnNa₂ concentration on properties of zinc-containing coatings on WE43 magnesium alloys. Surf. Coat. Technol., 2018,356:108-122. DOI URL
[4]	LU X P, BLAWERT C, HUANG Y D , et al. Plasma electrolytic oxidation coatings on Mg alloy with addition of SiO₂ particles. Electrochim. Acta, 2016,187:20-33. DOI URL
[5]	TOORANI M, ALIOFKHAZRAEI M, SABOUR ROUHAGHDAM A . Microstructural, protective, inhibitory and semiconducting properties of PEO coatings containing CeO₂ nanoparticles formed on AZ31 Mg alloy. Surf. Coat. Technol., 2018,352:561-580. DOI URL
[6]	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., 2019,360:153-171. DOI URL
[7]	BAI L J, DONG B X, CHEN G T , et al. Effect of positive pulse voltage on color value and corrosion property of magnesium alloy black micro-arc oxidation ceramic coating. Surf. Coat. Technol., 2019,374:402-408. DOI URL
[8]	EZHILSELVI V, NITHIN J, BALARAJU J N , et al. The influence of current density on the morphology and corrosion properties of MAO coatings on AZ31B magnesium alloy. Surf. Coat. Technol., 2016,288:221-229. DOI URL
[9]	LYU G H, CHEN H, GU W C , et al. Effects of current frequency on the structural characteristics and corrosion property of ceramic coatings formed on magnesium alloy by PEO technology. J. Mater. Process. Tech., 2008,208(1/2/3):9-13. DOI URL
[10]	ZOU B, LÜ G H, ZHANG G L , et al. Effect of current frequency on properties of coating formed by microarc oxidation on AZ91D magnesium alloy. Trans. Nonferrous Met. Soc. China, 2015,25(5):1500-1505. DOI URL
[11]	CHANG L R, CAO F H, CAI J S , et al. Influence of electric parameters on MAO of AZ91D magnesium alloy using alternative square-wave power source. Trans. Nonferrous Met. Soc. China, 2011,21(2):307-316. DOI URL
[12]	GU Y H, BANDOPADHYAY S, CHEN C F , et al. Effect of oxidation time on the corrosion behavior of micro-arc oxidation produced AZ31 magnesium alloys in simulated body fluid. J. Alloys Compd., 2012,543:109-117. DOI URL
[13]	GNEDENKOV S V, SINEBRYUKHOV S L, MASHTALYAR D V , et al. Composite coatings formed on the PEO-layers with the use of solutions of tetrafluoroethylene telomers. Surf. Coat. Technol., 2018,346:53-62. DOI URL
[14]	LUO D, LIU Y, YIN X M , et al. Corrosion inhibition of hydrophobic coatings fabricated by micro-arc oxidation on an extruded Mg-5Sn-1Zn alloy substrate. J. Alloys Compd., 2018,731:731-738. DOI URL
[15]	CUI L Y, LIU H P, ZHANG W L , et al. Corrosion resistance of a superhydrophobic micro-arc oxidation coating on Mg-4Li-1Ca alloy. J. Mater. Sci. Technol., 2017,33(11):1263-1271. DOI URL
[16]	QIU Z Z, SUN J, WANG R , et al. Magnet-induced fabrication of a superhydrophobic surface on ZK60 magnesium alloy. Surf. Coat. Technol., 2016,286:246-250. DOI URL
[17]	ZHU Y Y, WU G M, ZHANG Y H , et al. Growth and characterization of Mg(OH)₂ film on magnesium alloy AZ31. Appl. Surf. Sci., 2011, 257(14):6129-6137. DOI URL
[18]	WANG C M, SHEN J, ZHANG X K , et al. In vitrodegradation and cytocompatibility of a silane/Mg(OH)₂ composite coating on AZ31 alloy by spin coating. J. Alloys Compd., 2017,714:186-193. DOI URL
[19]	JIN Q, TIAN G Y, LI J X , et al. The study on corrosion resistance of superhydrophobic magnesium hydroxide coating on AZ31B magnesium alloy. Colloid. Surface A, 2019,577:8-16. DOI URL
[20]	JEONG H, YOO Y . Synthesis and characterization of thin films on magnesium alloy using a hydrothermal method. Surf. Coat. Technol., 2015,284:26-30.
[21]	ZHU Y Y, ZHAO Q, ZHANG Y H , et al. Hydrothermal synthesis of protective coating on magnesium alloy using de-ionized water. Surf. Coat. Technol., 2012,206(11/12):2961-2966. DOI URL
[22]	LI C Y, FAN X L, ZENG R C , et al. Corrosion resistance of in-situ growth of nano-sized Mg(OH)₂ on micro-arc oxidized magnesium alloy AZ31—influence of EDTA. J. Mater. Sci. Technol., 2019,35(6):1088-1098.
[23]	AMARAL L F, OLIVEIRA I R, BONADIA P , et al. Chelants to inhibit magnesia (MgO) hydration. Ceram. Int., 2011,37(5):1537-1542. DOI URL
[24]	DUAN H P, DU K Q, YAN C W , et al. Electrochemical corrosion behavior of composite coatings of sealed MAO film on magnesium alloy AZ91D. Electrochim. Acta, 2006,51(14):2898-2908. DOI URL
[25]	CUI L Y, ZENG R C, GUAN S K , et al. Degradation mechanism of micro-arc oxidation coatings on biodegradable Mg-Ca alloys: the influence of porosity. J. Alloys Compd., 2017,695:2464-2476. DOI URL
[26]	FENG J, CHEN Y, LIU X H , et al. In-situ hydrothermal crystallization Mg(OH)₂ films on magnesium alloy AZ91 and their corrosion resistance properties. Mater. Chem. Phys., 2013,143(1):322-329. DOI URL
[27]	ZHANG G, WU L, TANG A T , et al. 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. Corros. Sci., 2018,139:370-382. DOI URL
[28]	LIU Y, YIN X M, ZHANG J J , et al. A electro-deposition process for fabrication of biomimetic super-hydrophobic surface and its corrosion resistance on magnesium alloy. Electrochim. Acta, 2014,125:395-403. DOI URL
[29]	ZHANG G, WU L, TANG A T , et al. A novel approach to fabricate protective layered double hydroxide films on the surface of anodized Mg-Al alloy. Adv. Mater. Interfaces, 2017,4(12):1700163. DOI URL

Mg(OH)₂ Film on Micro-arc Oxidation Ceramic Coating of AZ31 Magnesium Alloy: Preparation and Corrosion Resistance

RichHTML

PDF (PC)

Knowledge

Cited

Abstract

Cite this article

share this article

Figures/Tables 10

References 29

Related Articles 15

Recommended Articles

Metrics

Comments

[1]	HONG Du, NIU Yaran, LI Hong, ZHONG Xin, ZHENG Xuebin. Tribological Properties of Plasma Sprayed TiC-Graphite Composite Coatings [J]. Journal of Inorganic Materials, 2022, 37(6): 643-650.
[2]	FU Ya-Kang,WENG Jie,LIU Yao-Wen,ZHANG Ke-Hong. hBMP-2 Contained Composite Coatings on Titanium Mesh Surface: Preparation and hBMP-2 Release [J]. Journal of Inorganic Materials, 2020, 35(2): 173-178.
[3]	YANG Shaohui, YAN Shufang, LI Shijiang, CHEN Weidong, DU Pei, MA Wen. Effect of Phase Duty Cycle on the Properties of ZrH_1.8 Surface Micro-arc Oxidized Ceramic Layer [J]. Journal of Inorganic Materials, 2020, 35(10): 1112-1116.
[4]	Yan-Zhe ZHOU, Min LIU, Kun YANG, Wei ZENG, Jin-Bing SONG, Chun-Ming DENG, Chang-Guang DENG. Microstructure and Property of MoSi₂-30Al₂O₃ Electrothermal Coating Prepared by Atmospheric Plasma Spraying [J]. Journal of Inorganic Materials, 2019, 34(6): 646-652.
[5]	DU Pei, YAN Shu-Fang, CHEN Wei-Dong, LI Shi-Jiang, MA Wen. Graphene Concentration on Micro-arc Oxidation Ceramic Layer of ZrH_1.8 Surface [J]. Journal of Inorganic Materials, 2019, 34(11): 1175-1180.
[6]	ZHANG Peng-Fei, YAN Shu-Fang, CHEN Wei-Dong, LI Shi-Jiang, GENG Yan-Hua, Wang Hong-Xing. Anode Voltage on Hydrogen Permeation Barrier Performance of Zirconium Hydride with Micro-arc Oxidation [J]. Journal of Inorganic Materials, 2018, 33(7): 793-797.
[7]	ZHANG Peng-Fei, YAN Shu-Fang, CHEN Wei-Dong, LI Shi-Jiang, ZHAO Li, WANG Hong-Xing. Influence of Reaction Time on Hydrogen Resistance Film on the Surface of ZrH_1.8 in Aluminate System [J]. Journal of Inorganic Materials, 2018, 33(3): 284-288.
[8]	YANG Tao, WANG Hai-Bin, SONG Xiao-Yan, LIU Xue-Mei, HOU Chao, WANG Xue-Zheng. Corrosion Resistance of HVOF-sprayed Nano- and Micon-structured WC-η Coatings against Molten Zinc [J]. Journal of Inorganic Materials, 2017, 32(8): 806-812.
[9]	WANG Xue-Zheng, WANG Hai-Bin, LIU Xue-Mei, YANG Tao, SONG Xiao-Yan. Grain Growth Inhibitor on the WC-Co Cemented Carbide Coating [J]. Journal of Inorganic Materials, 2017, 32(8): 813-818.
[10]	LUO Jun-Ming, WU Xiao-Hong, XU Ji-Lin. Electrolytic Composition on Wear Resistance and Corrosion Resistance of the Micro-arc Oxidation Coatings on TiC_P/Ti6Al4V Composites [J]. Journal of Inorganic Materials, 2017, 32(4): 418-424.
[11]	LI Hang, LU Song-Tao, QIN Wei, WU Xiao-Hong. Current Density on Microstructure and Thermal Control Performances of MgO-ZnO Ceramic Coatings [J]. Journal of Inorganic Materials, 2017, 32(12): 1292-1298.
[12]	HE Ling, LI Qian-Kun, LI Weng-Sheng, CUI Shuai. Synthesis and Properties of Self-sensitization Luminescent Composite Coatings [J]. Journal of Inorganic Materials, 2017, 32(1): 56-62.
[13]	WAN Jian-Feng, HU De-Sheng, LU Peng-Hui, LIN Bi-Zhou, CHEN Yi-Lin, GAO Bi-Fen. Preparation of Anatase TiO₂ Nanocube with Exposed (001) Facet and Its Photocatalytic Properties [J]. Journal of Inorganic Materials, 2016, 31(8): 845-849.
[14]	LIU Ze-Hua, QI Qian, YAN Yong-Jie, ZHANG Hui, LIU Xue-Jian, LUO Hong-Jie, HUANG Zheng-Ren. Effect of Residual Phase and Grain Size on Corrosion Resistance of SiC Ceramics in Mixed HF-HNO₃ Acid Solution [J]. Journal of Inorganic Materials, 2016, 31(6): 661-666.
[15]	GUO Wen, MI Guo-Ji, ZHANG Jin-Long, WANG Zhen-Ya. Friction and Wear Behavior of Ni-SiC Composite Coating Prepared on TA15 Alloy [J]. Journal of Inorganic Materials, 2016, 31(2): 195-200.