Mechanism of microarc oxidation on AZ91D Mg alloy induced by β-Mg₁₇Al₁₂ phase

Abstract

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution of β-Mg₁₇Al₁₂ phase in AZ91D Mg alloy. Two kinds of nano-particles (ZrO₂ and TiO₂) were designed to be added into the substrate of Mg alloy by friction stir processing (FSP). Then, Mg alloy sample designed with different precipitated morphology of β-Mg₁₇Al₁₂ phase was treated by microarc oxidation (MAO) in Na₃PO₄/Na₂SiO₃ electrolyte. The characteristics and performance of the MAO coating was analyzed using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle meter, and potentiodynamic polarization. It was found that the coarse α-Mg grains in extruded AZ91D Mg alloy were refined by FSP, and the β-Mg₁₇Al₁₂ phase with reticular structure was broken and dispersed. The nano-ZrO₂ particles were pinned at the grain boundary by FSP, which refined the α-Mg grain and promoted the precipitation of β-Mg₁₇Al₁₂ phase in grains. It effectively inhibited the “cascade” phenomenon of microarcs, which induced the uniform distribution of discharge pores. The MAO coating on Zr-FSP sample had good wettability and corrosion resistance. However, TiO₂ particles were hardly detected in the coating on Ti-FSP sample.

Keywords

AZ91D Mg alloy / microarc oxidation / friction stir processing / ZrO₂ / TiO₂ / β-Mg₁₇Al₁₂

References

[[1]] Hegy AA, Smith R, Gauthier ER, Gray-Munro JE. Investigation of a cyanine dye assay for the evaluation of the biocompatibility of magnesium alloys by direct and indirect methods. Bioact. Mater., 2020, 5(1): 26, pmcid: 6957867

[[2]] Chen HW, Yuan B, Zhao R, et al.. Evaluation on the corrosion resistance, antibacterial property and osteogenic activity of biodegradable Mg–Ca and Mg–Ca–Zn–Ag alloys. J. Magnesium Alloys, 2022, 10(12): 3380,

[[3]] S.S. Park, U. Farwa, I. Park, B.G. Moon, S.B. Im, and B.T. Lee, In-vivo bone remodeling potential of Sr–d-Ca–P/PLLA-HAp coated biodegradable ZK60 alloy bone plate, Mater. Today Bio, 18(2023), art. No. 100533.

[[4]] Yao WH, Wu L, Wang JF, et al.. Micro-arc oxidation of magnesium alloys: A review. J. Mater. Sci. Technol., 2022, 118: 158,

[[5]] Fattah-alhosseini A, Chaharmahali R, Babaei K, Nouri M, Keshavarz MK, Kaseem M. A review of effective strides in amelioration of the biocompatibility of PEO coatings on Mg alloys. J. Magnesium Alloys, 2022, 10(9): 2354,

[[6]] D.D. Wang, X.T. Liu, Y. Wang, et al., Role of the electrolyte composition in establishing plasma discharges and coating growth process during a micro-arc oxidation, Surf. Coat. Technol., 402(2020), art. No. 126349.

[[7]] X.N. Ly, S. Yang, and T. Nguyen, Effect of equal channel angular pressing as the pretreatment on microstructure and corrosion behavior of micro-arc oxidation (MAO) composite coating on biodegradable Mg–Zn–Ca alloy, Surf. Coat. Technol., 395(2020), art. No. 125923.

[[8]] Mi T, Jiang B, Liu Z, et al.. Self-organization kinetics of microarc oxidation: Nonequilibrium-state electrode reaction kinetics. J. Electrochem. Soc., 2016, 163(5): C184,

[[9]] L. Casanova, M. Arosio, M.T. Hashemi, M. Pedeferri, G.A. Botton, and M. Ormellese, A nanoscale investigation on the influence of anodization parameters during plasma electrolytic oxidation of titanium by high-resolution electron energy loss spectroscopy, Appl. Surf. Sci., 570(2021), art. No. 151133.

[[10]] D.S. Tsai and C.C. Chou, Influences of growth species and inclusions on the current–voltage behavior of plasma electrolytic oxidation: A review, Coatings, 11(2021), No. 3, art. No. 270.

[[11]] Liu CC, Xu T, Shao QY, et al.. Effects of beta phase on the growth behavior of plasma electrolytic oxidation coating formed on magnesium alloys. J. Alloys Compd., 2019, 784: 414,

[[12]] Xue YN, Pang X, Jiang BL, Jahed H, Wang D. Characterization of the corrosion performances of as-cast Mg–Al and Mg–Zn magnesium alloys with microarc oxidation coatings. Mater. Corros., 2020, 71(6): 992,

[[13]] E.Y. Liu, Y.F. Niu, S.R. Yu, et al., Micro-arc oxidation behavior of fly ash cenospheres/magnesium alloy degradable composite and corrosion resistance of coatings, Surf. Coat. Technol., 391(2020), art. No. 125693.

[[14]] Wang YQ, Wang XJ, Zhang T, Wu K, Wang FH. Role of β phase during microarc oxidation of Mg alloy AZ91D and corrosion resistance of the oxidation coating. J. Mater. Sci. Technol., 2013, 29(12): 1129,

[[15]] Chen Y, Yang YG, Zhang W, Zhang T, Wang FH. Influence of second phase on corrosion performance and formation mechanism of PEO coating on AZ91 Mg alloy. J. Alloys Compd., 2017, 718: 92,

[[16]] Mishra RS, Mahoney MW, McFadden SX, Mara NA, Mukherjee AK. High strain rate superplasticity in a friction stir processed 7075 Al alloy. Scr. Mater., 1999, 42(2): 163,

[[17]] Maqbool A, Khan NZ, Siddiquee AN, Badruddin IA, Hussien M, Khan MI. Overcoming challenges in using magnesium-based materials for industrial applications using friction-stir engineering. Mater. Sci. Technol., 2023, 39(9): 1039,

[[18]] Eivani AR, Mehdizade M, Chabok S, Zhou J. Applying multi-pass friction stir processing to refine the microstructure and enhance the strength, ductility and corrosion resistance of WE43 magnesium alloy. J. Mater. Res. Technol., 2021, 12: 1946,

[[19]] Kumar TS, Shalini S, Thankachan T. Friction stir processing based surface modification of AZ31 magnesium alloy. Mater. Manuf. Process., 2023, 38(11): 1426,

[[20]] Khan MA, Butola R, Gupta N. A review of nanoparticle reinforced surface composites processed by friction stir processing. J. Adhes. Sci. Technol., 2023, 37(4): 565,

[[21]] Qiu T, Tan LM, Zhai DJ, Ni P, Shen J. Correlation between plasma electrolytic oxidation coating on Ti₆Al₄V alloy and cathode current. Metall. Mater. Trans. A, 2023, 54(1): 333,

[[22]] Wang XM, Zhang FQ. Influence of anions in phosphate and tetraborate electrolytes on growth kinetics of microarc oxidation coatings on Ti₆Al₄V alloy. Trans. Nonferrous Met. Soc. China, 2022, 32(7): 2243,

[[23]] Mortazavi G, Jiang JC, Meletis EI. Investigation of the plasma electrolytic oxidation mechanism of titanium. Appl. Surf. Sci., 2019, 488: 370,

[[24]] Yi YS, Meng Y, Li DQ, Sugiyama S, Yanagimoto J. Partial melting behavior and thixoforming properties of extruded magnesium alloy AZ91 with and without addition of SiC particles with a volume fraction of 15%. J. Mater. Sci. Technol., 2018, 34(7): 1149,

[[25]] Gao J, Jiang S, Zhang H, et al.. Facile route to bulk ultrafine-grain steels for high strength and ductility. Nature, 2021, 590(7845): 262, pmcid: 7888382

[[26]] Y. Wang, B.W. Yang, M.Q. Gao, E.T. Zhao, and R.G. Guan, Microstructure evolution, mechanical property response and strengthening mechanism induced by compositional effects in Al–6Mg alloys, Mater. Des., 220(2022), art. No. 110849.

[[27]] Fatimah S, Yang HW, Kamil MP, Ko YG. Control of surface plasma discharge considering the crystalline size of Al substrate. Appl. Surf. Sci., 2019, 477: 60,

[[28]] Darband GB, Aliofkhazraei M, Hamghalam P, Valizade N. Plasma electrolytic oxidation of magnesium and its alloys: Mechanism, properties and applications. J. Magnesium Alloys, 2017, 5(1): 74,

[[29]] Zhai DJ, Qiu T, Shen J, Feng KQ. Mechanism of tetraborate and silicate ions on the growth kinetics of microarc oxidation coating on a Ti₆Al₄V alloy. RSC Adv., 2023, 13(8): 5382, pmcid: 9923455

[[30]] Zhai DJ, Feng KQ, Yue HF. Growth kinetics of microarc oxidation TiO₂ ceramic film on Ti₆Al₄V alloy in tetraborate electrolyte. Metall. Mater. Trans. A, 2019, 50(5): 2507,

[[31]] Wu T, Blawert C, Serdechnova M, et al.. PEO processing of AZ91Nd/Al₂O₃ MMC-the role of alumina fibers. J. Magnesium Alloys, 2022, 10(2): 423,

[[32]] Lin JW, He SQ, Wang XX, Zhang HH, Zhan YH. Removal of phosphate from aqueous solution by a novel Mg(OH)₂/ZrO₂ composite: Adsorption behavior and mechanism. Colloids Surf. A, 2019, 561: 301,

[[33]] S.K. Yang, C. Wang, F.Z. Li, et al., One-step in situ growth of a simple and efficient pore-sealing coating on micro-arc oxidized AZ31B magnesium alloy, J. Alloys Compd., 909(2022), art. No. 164710.

[[34]] Liu L, Yu SR, Zhu G, et al.. Corrosion and wear resistance of micro-arc oxidation coating on glass microsphere reinforced Mg alloy composite. J. Mater. Sci., 2021, 56(27): 15379,

[[35]] M. Stern, Electrochemical polarization, J. Electrochem. Soc., 104(1957), No. 9, art. No. 559.

[[36]] Song GL, Atrens A, Wu XL, Zhang B. Corrosion behaviour of AZ21, AZ501 and AZ91 in sodium chloride. Corros. Sci., 1998, 40(10): 1769,

[[37]] C.H. Shih, C.Y. Huang, T.H. Hsiao, and C.S. Lin, The effect of the secondary phases on the corrosion of AZ31B and WE43–T5 Mg alloys, Corros. Sci., 211(2023), art. No. 110920.

[[38]] Muldoon J, Bucur CB, Gregory T. Fervent hype behind magnesium batteries: An open call to synthetic chemists—Electrolytes and cathodes needed. Angew. Chem. Int. Ed., 2017, 56(40): 12064,

[[39]] S.W. Guan, M. Qi, Y.D. Li, and W.Q. Wang, Morphology evolution of the porous coatings on Ti–xAl alloys by Al adding into Ti during micro-arc oxidation in Na₂B₄O₇ electrolyte, Surf. Coat. Technol., 395(2020), art. No. 125948.