Influence of the lithium content on the negative difference effect of Mg-Li alloys

doi:10.1016/j.jmst.2020.03.046

Abstract

Abstract:

The so-called ‘negative difference effect’ (NDE) was often defined by the increasing rate of hydrogen evolution from magnesium (Mg) surface under anodic polarization. In this work, a series of electrochemical tests and microstructure observations were performed to provide an evidence that the NDE of Mg-Li alloys can be retarded by increasing lithium content. Potentiostatic, galvanostatic and potentiodynamic polarization experiments using Mg-xLi (x = 4, 7.5 and 14 wt%) alloys electrodes indicated that Mg-4Li alloy maintained the enhancing NDE prior to anodic dissolution as that of conventional Mg alloys. However, the emergence of β-Li phase weakened the NDE of duplex Mg-7.5Li alloy at a low anodic current density, but it was still enhanced apparently after a high applied anodic value (more than 2 mA/cm ²). The surface observations, including the plane and cross-sectional morphologies, confirmed that the cracked surface film derived from the anodic dissolution resulted in the catalytic activity of NDE for Mg-4Li and Mg-7.5Li alloys. Furthermore, the NDE of Mg-14Li alloy was suppressed obviously after a prior applied anodic polarization, which was attributed to the persistent and integrated surface film which endured a higher level of applied anodic potential and current.

Key words: Mg-Li alloy, Negative difference effect, Electrochemical property, Corrosion, Anodic dissolution

C.Q. Li, D.K. Xu, Z.R. Zhang, E.H. Han. Influence of the lithium content on the negative difference effect of Mg-Li alloys[J]. J. Mater. Sci. Technol., 2020, 57: 138-145.

Figures/Tables 12

Table 1 Chemical compositions (wt%) of Mg-4Li, Mg-7.5Li and Mg-14Li alloys.

Alloys	Mg	Li	Al	Zn	Cu	Fe	Si	Mn	Ni	Co
Mg-4Li	Bal.	4.21	0.002	0.001	0.002	0.006	0.01	0.01	<0.001	<0.001
Mg-7.5Li	Bal.	7.47	0.001	0.002	0.002	0.005	0.01	0.02	<0.001	<0.001
Mg-14Li	Bal.	13.66	0.002	0.001	0.001	0.005	0.01	0.01	<0.001	<0.001

Fig. 1. SEM images of (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys.

Fig. 2. Typical potentiodynamic polarization curve for three Mg-Li alloys in 0.1 M NaCl at 25 °C.

Table 2 Tafel fitting results derived from the polarization curves of Mg-4Li, Mg-7.5Li and Mg-14Li alloys tested in 0.1 M NaCl solution.

Alloys	E_corr (V vs. SCE)	j_corr (μA cm^-2)
Mg-4Li	-1.56 ± 0.02	5.41 ± 0.28
Mg-7.5Li	-1.55 ± 0.01	5.23 ± 0.21
Mg-14Li	-1.64 ± 0.02	6.86 ± 0.25

Fig. 3. Applied and measured electrochemical currents and potentials arising from the application of a custom polarization regime for (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys in 0.1 M NaCl at 25 °C. The regime consisted of increasing the applied anodic current density in a stepwise manner (from 20 to 2500 μA/cm2).

Fig. 4. Summary of data collected as a result of the custom polarization regime from 20 μA/cm2 to 20 mA/cm2 for (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys.

Fig. 5. Typical potentiodynamic cathodic polarization curve of (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys after anodic dissolution/conditioning for 2 min at 10 mA/cm2.

Fig. 6. Typical surface morphologies of (a, d) Mg-4Li, (b, e) Mg-7.5Li and (c, f) Mg-14Li alloys after potentiodynamic cathodic polarization following (a-c) OCP holding for 10 min and (d-f) anodic dissolution/conditioning for 2 min at 10 mA/cm2. Higher-magnification observation to the images (a), (b), (c) and (f) are inserted.

Fig. 7. EIS plots of (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys applied with OCP and +100 mV vs. OCP in 0.1 M NaCl solution.

Fig. 8. Surface morphologies of (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys following anodic dissolution at +100 mV above OCP for 10 min, respectively. Images (d), (e) and (f) are higher-magnification observation to the areas defined in images (a), (c) and (e).

Fig. 9. Cross-sectional morphologies of (a) Mg-4Li, (b) Mg-7.5Li and (c) Mg-14Li alloys following anodic dissolution at +100 mV above OCP for 10 min. Images (d), (e) and (f) are higher-magnification observation to images (a), (b) and (c), respectively.

Fig. 10. XPS analysis of the surface film on Mg-4Li, Mg-7.5Li and Mg-14Li alloys after immersion in 0.1 M NaCl solution for 2 h.

References 62

[1]	B.J. Wang, D.K. Xu, S.D. Wang, L.Y. Sheng, R.C. Zeng, E.H. Han, Int. J. Fatigue 120 (2019) 46-55. DOI URL
[2]	S.Q. Yin, W.C. Duan, W.H. Liu, L. Wu, J.M. Yu, Z.L. Zhao, M. Liu, P. Wang, J.Z. Cui, Z.Q. Zhang, Corros. Sci. (2019), 108419.
[3]	M. Duan, L. Luo, Y. Liu, J. Alloys Compd. 823(2020), 153691. DOI URL
[4]	F. Zhong, H.J. Wu, Y.L. Jiao, R.Z. Wu, J.H. Zhang, L.G. Hou, J. Mater. Sci. Technol. 39(2020) 124-134. DOI URL
[5]	J.H. Zhang, S.J. Liu, R.Z. Wu, L.G. Hou, M.L. Zhang, J. Magnes. Alloys 6 (2018) 277-291. DOI URL
[6]	X.J. Wang, D.K. Xu, R.Z. Wu, X.B. Chen, Q.M. Peng, L. Jin, Y.C. Xing, Z.Q. Zhang, Y. Liu, X.H. Chen, G, G. Chen, K.K. Deng, H.Y. Wang, J. Mater. Sci. Technol. 34(2018) 245-247. DOI URL
[7]	L. Wu, X.X. Ding, Z.C. Zheng, A.T. Tang, G. Zhang, A. Atrens, F.S. Pan, J. Mater. Sci. Technol. (2019), http://dx.doi.org/10.1016/j.jmst.2019.09.031. DOI URL PMID
[8]	B.J. Wang, D.K. Xu, L.Y. Sheng, E.H. Han, J. Sun, J. Mater. Sci. Technol. 35(2019) 2423-2429. DOI URL
[9]	C.Q. Li, D.K. Xu, Z.R. Zeng, B.J. Wang, L.Y. Sheng, X.B. Chen, E.H. Han, Mater. Des. 121(2017) 430-441. DOI URL
[10]	B.J. Wang, D.K. Xu, S.D. Wang, E.H. Han, Front. Mech. Eng. 14(2019) 113-127. DOI URL
[11]	B.J. Wang, D.K. Xu, J. Sun, E.H. Han, Corros. Sci. 157(2019) 347-356. DOI URL
[12]	S. Lebouil, O. Gharbi, P. Volovitch, K. Ogle, Corrosion 71 (2015) 234-241. DOI URL
[13]	J.R. Li, Z.Y. Chen, J.P. Jing, J. Hou, J. Mater, Sci. Technol. 41(2020) 33-42.
[14]	S. Fajardo, G.S. Frankel, Electrochem. Commun. 84(2017) 36-39. DOI URL
[15]	T.W. Cain, I. Gonzalez-Afanador, N. Birbilis, J.R. Scully, J. Electrochem. Soc. 164(2017) C300-C311. DOI URL
[16]	S. Fajardo, G.S. Frankel, Electrochim. Acta 165 (2015) 255-267. DOI URL
[17]	M. Curioni, Electrochim. Acta 120 (2014) 284-292. DOI URL
[18]	J.A. Yuwono, N. Birbilis, C.D. Taylor, K.S. Williams, A.J. Samin, N.V. Medhekar, Corros. Sci. 147(2019) 53-68. DOI URL
[19]	J.A. Yuwono, C.D. Taylor, G.S. Frankel, N. Birbilis, S. Fajardo, Electrochem. Commun. 104(2019), 106482. DOI URL
[20]	S. Fajardo, C.F. Glover, G. Williams, G.S. Frankel, Electrochim. Acta 212 (2016) 510-521. DOI URL
[21]	S. Fajardo, C.F. Glover, G. Williams, G.S. Frankel, Corrosion 73 (2017) 482-493. DOI URL
[22]	P. Gore, V.S. Raja, N. Birbilis, J. Electrochem. Soc. 165(2018) C849-C859. DOI URL
[23]	C.Q. Li, D.K. Xu, X.-B. Chen, B.J. Wang, R.Z. Wu, E.H. Han, N. Birbilis, Electrochim. Acta 260 (2018) 55-64. DOI URL
[24]	C.Q. Li, D.K. Xu, B.J. Wang, L.Y. Sheng, R.Z. Wu, E.H. Han, J. Mater. Sci. Technol. 35(2019) 2477-2484. DOI URL
[25]	B.J. Wang, J.Y. Luan, D.K. Xu, J. Sun, C.Q. Li, E.H. Han, Acta Metall. Sin.(Engl. Lett.) 32(2019) 1-9.
[26]	C.Q. Li, D.K. Xu, B.J. Wang, L.Y. Sheng, Y.X. Qiao, E.H. Han, Sci. Rep. 7(2017) 40078. DOI URL PMID
[27]	W.Q. Xu, N. Birbilis, G. Sha, Y. Wang, J. Daniels, Y. Xiao, M. Ferry, Nat. Mater. 14(2015) 1229-1235. DOI URL PMID
[28]	L.F. Hou, M. Raveggi, X.B. Chen, W.Q. Xu, K.J. Laws, Y.H. Wei, M. Ferry, N. Birbilis, J. Electrochem. Soc. 163(2016) C324-C329. DOI URL
[29]	A. Samaniego, N. Birbilis, X. Xia, G.S. Frankel, Corrosion 71 (2015) 224-233. DOI URL
[30]	N. Birbilis, A.D. King, S. Thomas, G.S. Frankel, J.R. Scully, Electrochim. Acta 132 (2014) 277-283. DOI URL
[31]	H.G. Liu, F.Y. Cao, G.L. Song, D.J. Zheng, Z.M. Shi, M.S. Dargusch, A. Atrens, J. Mater. Sci. Technol. 35(2019) 2003-2016. DOI URL
[32]	C.Q. Li, D.K. Xu, S. Yu, L.Y. Sheng, E.H. Han, J. Mater. Sci. Technol. 33(2017) 475-480. DOI URL
[33]	A.A. Nayeb-Hashemi, J.B. Clark, Bull. Alloy Phase Diagr. 5(1984) 365-374. DOI URL
[34]	R.L. Liu, J.R. Scully, G. Williams, N. Birbilis, Electrochim. Acta 260 (2018) 184-195. DOI URL
[35]	R.L. Liu, S. Thomas, J.R. Scully, G. Williams, N. Birbilis, Corrosion 73 (2017) 494-505. DOI URL
[36]	L.G. Bland, K. Gusieva, J.R. Scully, Electrochim. Acta 227 (2017) 136-151. DOI URL
[37]	M. Taheri, R.C. Phillips, J.R. Kish, G.A. Botton, Corros. Sci. 59(2012) 222-228. DOI URL
[38]	C.Y. Li, C.Y. Li, X.L. Fan, R.C. Zeng, L.Y. Cui, S.Q. Li, F. Zhang, Q.K. He, M. Bobby Kannan, H.W. Jiang, D.C. Chen, S.K. Guan, J. Mater. Sci. Technol. 35(2019) 1088-1098.
[39]	Y.M. Yan, P. Zhou, O. Gharbi, Z.R. Zeng, X.B. Chen, P. Volovitch, K. Ogle, N. Birbilis, Electrochem. Commun. 99(2019) 46-50. DOI URL
[40]	Y.M. Yan, O. Gharbi, A. Maltseva, X.B. Chen, Z.R. Zeng, S.W. Xu, W.Q. Xu, P. Volovitch, M. Ferry, N. Birbilis, Corrosion 75 (2019), 89-89.
[41]	Y.M. Yan, Y. Qiu, O. Gharbi, N. Birbilis, P.N.H. Nakashima, Appl. Surf. Sci. 494(2019) 1066-1071. DOI URL
[42]	S.S. Jamali, S.E. Moulton, D.E. Tallman, Y. Zhao, J. Weber, G.G. Wallace, Electrochem. Commun. 76(2017) 6-9. DOI URL
[43]	Y.W. Song, D.Y. Shan, R.S. Chen, E.H. Han, J. Alloys Compd. 484(2009) 585-590. DOI URL
[44]	R.C. Zeng, L. Sun, Y.F. Zheng, H.Z. Cui, E.H. Han, Corros. Sci. 79(2014) 69-82. DOI URL
[45]	L.G. Bland, A.D. King, N. Birbilis, J.R. Scully, Corrosion 71 (2014) 128-145. DOI URL
[46]	V. Shkirskiy, A.D. King, O. Gharbi, P. Volovitch, J.R. Scully, K. Ogle, N. Birbilis, Chem. Phys. Chem. 16(2015) 536-539. DOI URL PMID
[47]	A.D. King, N. Birbilis, J.R. Scully, Electrochim. Acta 121 (2014) 394-406. DOI URL
[48]	Y.W. Song, D.Y. Shan, R.S. Chen, E.H. Han, Corros. Sci. 51(2009) 1087-1094. DOI URL
[49]	G. Williams, N. Birbilis, H.N. McMurray, Electrochem.Commun. 36(2013) 1-5.
[50]	Z.P. Cano, M. Danaie, J.R. Kish, J.R. McDermid, G.A. Botton, G. Williams, Corrosion 71 (2015) 146-159. DOI URL
[51]	E. Ghali, W. Dietzel, K.U. Kainer, J. Mater. Eng. Perform. 22(2013) 2875-2891. DOI URL
[52]	G.L. Song, P.E. Gannon, Magnes. Technol. (2016) 285-290.
[53]	F.Y. Cao, Z.M. Shi, J. Hofstetter, P.J. Uggowitzer, G.L. Song, M. Liu, A. Atrens, Corros. Sci. 75(2013) 78-99. DOI URL
[54]	Y. Cho, J.Y. Lee, A.D. Bokare, S.B. Kwon, D.S. Park, W.S. Jung, J.S. Choi, Y.M. Yang, J.Y. Lee, W.Y. Choi, J. Ind. Eng. Chem. 22(2015) 350-356. DOI URL
[55]	S. Satyapal, T. Filburn, J. Trela, Energy Fuel 15 (2001) 250-255. DOI URL
[56]	G.L. Song, A. Atrens, Adv. Eng. Mater. 1(1999) 11-33. DOI URL
[57]	S. Bender, J. Goellner, A. Heyn, S. Schmigalla, Mater. Corros. 63(2012) 707-712.
[58]	S. Fajardo, J. Bosch, G.S. Frankel, Corros. Sci. 146(2019) 163-171. DOI URL
[59]	S.H. Salleh, S. Thomas, J.A. Yuwono, K. Venkatesan, N. Birbilis, Electrochim. Acta 161 (2015) 144-152. DOI URL
[60]	M. Curioni, Electrochim. Acta 120 (2014) 284-292. DOI URL
[61]	I.A. Gvozdkov, V.A. Belyaev, S.N. Potapov, V.N. Verbetskii, S.V. Mitrokhin, A.A. Tepanov, Inorg. Mater. 10(2019) 870-874.
[62]	X. Xia, C.H.J. Davies, J.F. Nie, N. Birbilis, Corrosion 71 (2015) 38-49. DOI URL