Non-destructive corrosion study on a magnesium alloy with mechanical properties tailored for biodegradable cardiovascular stent applications

doi:10.1016/j.jmst.2020.07.006

Abstract

Abstract:

An Mg-2Zn-0.6Zr-0.6Nd alloy for biodegradable cardiovascular stent applications was prepared through indirect extrusion. The alloy exhibited a superior combination of tensile yield strength (TYS), ultimate tensile strength (UTS) and elongation (EL) of about 269 MPa, 298 MPa and 25.6 %, respectively. In addition, the non-destructive electrochemical frequency modulation (EFM) technique was used for the first time to investigate the corrosion behavior of Mg alloys combined with electrochemical impedance spectroscopy (EIS) in Dulbecco’s Modified Eagle’s Medium (DMEM) and in Hank’s solution. Compared with the corrosion rate of 0.07 mm/year in Hank’s solution, lower corrosion rate of 0.03 mm/year was achieved in DMEM. The significant differences between the corrosion rate trends were discussed and related with the composition of the corrosion layer formed. Depending on the biomimetic fluids tested, different corrosion products were precipitated on the alloy’s surface: a compact and homogeneous layer of Mg_xCa_y(PO₄)_z and Zn(OH)₂ and organic compounds was formed in DMEM, whereas a partial coverage of Mg_xCa_y(PO₄)_z and Mg(OH)₂ was formed in Hank’s solution.

Key words: Mg-Zn-Zr-Nd alloy, Mechanical property, Corrosion, EIS, EFM

Changhong Cai, Marta M. Alves, Renbo Song, Yongjin Wang, Jingyuan Li, M. Fátima Montemor. Non-destructive corrosion study on a magnesium alloy with mechanical properties tailored for biodegradable cardiovascular stent applications[J]. J. Mater. Sci. Technol., 2021, 66: 128-138.

Figures/Tables 13

Table 1 Chemical composition of Mg-2Zn-0.6Zr-0.6Nd alloy (wt.%).

Zn	Zr	Nd	Fe	Ni	Cu	Mg
1.94	0.52	0.56	<0.005	<0.002	<0.005	Bal.

Fig. 1. Microstructure and mechanical properties of the as-cast alloy: (a) SEM image, (b) EPMA analysis, (c) BF-TEM image of secondary phase with the inset showing the elemental analysis in point A and (d) engineering stress-strain curve.

Fig. 2. EBSD analyses of IPF maps, average grain size and {0002} and {10-10} pole figures of DRXed grains of the extruded Mg-2Zn-0.6Zr-0.6Nd alloys in ED-TD plane: (a-c) #1 alloy, (d-f) #2 alloy.

Fig. 3. TEM analyses of extruded Mg-2Zn-0.6Zr-0.6Nd alloys: (a) BF-TEM image of #1 alloy, (b) BF-TEM image of #2 alloy and SAEDs of T3 phase, (c) BF-TEM images of Mg(Zn,Zr) phases and (d) HR-TEM FFT, and IFFT of Mg(Zn,Zr) phase.

Fig. 4. Mechanical properties of extruded Mg-2Zn-0.6Zr-0.6Nd in this study and other reported extruded Mg alloys: (a) tensile stress-strain curves, (b) compression stress-strain curves, (c) comparison of TYS vs. EL and (d) comparison of TYS vs. alloying content.

Table 2 Mechanical properties of extruded Mg-2Zn-0.6Zr-0.6Nd alloys.

Alloys	TYS (MPa)	UTS (MPa)	EL (%)	CYS (MPa)	CYS/TYS
#1 Alloy	242 ± 5	274 ± 5	26.1 ± 1.5	207 ± 4	0.85 ± 0.03
#2 Alloy	269 ± 6	298 ± 8	25.6 ± 1.1	221 ± 6	0.82 ± 0.04

Fig. 5. SEM characterization of #2 alloy before immersion and after immersion in in media simulating the biomimetic fluids for 24 h at 37 ℃ by SEM: (a) before immersion, (b) immersion in DMEM, (c) immersion in Hank’s solution, (d) cross-section in DMEM and (e) cross-section in Hank’s solution; numbers represent spots where chemical analysis was performed by EDS (Table 3).

Table 3 Surface chemical compositions measured by EDS (at.%) marked in Fig. 5.

Point	Mg	O	C	P	Ca	Zn	S	Cl	Nd
1	7.1	42.1	30.7	6.8	7.7	3.4	1.2	/	1.0
2	9.2	42.3	29.4	8.0	7.5	2.4	1.2	/	/
3	69.4	13.9	14.1	1.3	0.7	0.6	/	/	/
4	9.9	54.2	12.8	9.5	12.7	0.3	/	0.6	/

Fig. 6. EIS results of #2 alloy in DMEM or Hank’s solution at 37 ℃: (a) Nyquist plots in DMEM, (b) Bode plots of |Z| vs. Frequency in DMEM, (c) Bode plots of degree vs. Frequency in DMEM, (d) Nyquist plots in Hank’s solution, (e) Bode plots of |Z| vs. Frequency in Hank’s solution, (f) Bode plots of degree vs. Frequency in Hank’s solution and (g) equivalent electric circuit used to fit EIS data.

Table 4 Fitting results of EIS using equivalent circuit.

Biomimetic medium	Time	χ²	R₁ (Ω cm²)	CPE₁(F cm^-2)	n₁	R₂ (Ω cm²)	CPE₂(F cm^-2)	n₂	R₃ (Ω cm²)
DMEM	1h	2.0 × 10^-4	53.1	7.2 × 10^-6	0.61	1396	4.2 × 10^-6	0.91	4952
	24 h	6.2 × 10^-3	54.7	3.2 × 10^-7	0.69	18233	1.8 × 10^-6	0.81	125120
	48h	8.0 × 10^-3	53.9	3.1 × 10^-7	0.68	20276	1.4 × 10^-6	0.80	174305
	72 h	7.9 × 10^-3	54.1	3.0 × 10^-7	0.69	19502	1.4 × 10^-6	0.79	203602
Hank’s solution	1h	2.3 × 10^-3	42.7	6.8 × 10^-7	0.75	1925	2.4 × 10^-6	0.86	91938
	24 h	6.1 × 10^-3	43.7	3.5 × 10^-7	0.71	8052	2.9 × 10^-6	0.80	70111
	48h	5.8 × 10^-3	43.1	2.3 × 10^-7	0.62	6695	2.8 × 10^-6	0.74	106030
	72 h	8.2 × 10^-3	43.6	8.3 × 10^-7	0.61	4784	2.1 × 10^-6	0.80	106543

Fig. 7. Intermodulation spectra of #2 alloy in DMEM or Hank’s solution at 37 ℃ obtained by EFM technique: (a) DMEM - 1 h, (b) DMEM - 24 h, (c) DMEM - 48 h, (d) DMEM - 72 h, (e) Hank’s solution - 1 h, (f) Hank’s solution - 24 h, (g) Hank’s solution - 48 h and (h) Hank’s solution - 72 h.

Table 5 Electrochemical kinetic parameters calculate by EFM technique.

Biomimetic medium	Time	i_corr (μA cm^-2)	β_a(mV·dec^-1)	-β_c(mV·dec^-1)	Corrosion rate (mm year^-1)	CF(2)	CF(3)
DMEM	1h	16.20	316.5	2170	1.50	2.00	3.11
	24 h	0.53	225.8	474.7	0.049	2.01	3.32
	48h	0.37	213.8	435.5	0.034	1.97	3.16
	72 h	0.32	205.9	386.7	0.029	1.97	3.44
Hank’s solution	1h	0.76	235.8	699.4	0.070	1.98	3.11
	24 h	0.91	228.7	493.9	0.085	1.99	2.56
	48h	0.72	222.4	447.3	0.067	1.91	2.93
	72 h	0.72	222.7	448.5	0.067	1.92	3.43

Fig. 8. Summarized EFM results of #2 alloy in DMEM or Hank’s solution at 37 ℃: (a) intermodulation spectra in DMEM, (b) intermodulation spectra in Hank’s solution and (c) corrosion rate changes with immersion time.

References 59

[1]	W. Xu, N. Birbilis, G. Sha, Y. Wang, J.E. Daniels, Y. Xiao, M. Ferry, Nat. Mater. 14 (2015) 1229-1235. URL PMID
[2]	J. Wang, Y. Ma, S. Guo, W. Jiang, Q. Liu, Mater. Des. 153 (2018) 308-316.
[3]	B. Zberg, P.J. Uggowitzer, J.F. Löffler, Nat. Mater. 8 (2009) 887-891. URL PMID
[4]	Y. Li, J. Zhou, P. Pavanram, M.A. Leeflang, L.I. Fockaert, B. Pouran, N. Tümer, K.U. Schröder, J.M.C. Mol, H. Weinans, H. Jahr, A.A. Zadpoor, Acta Biomater. 67 (2018) 378-392. URL PMID
[5]	J. Chen, L. Tan, X. Yu, K. Yang, J. Mater. Sci. Technol. 35 (2019) 503-511.
[6]	M.P. Staiger, A.M. Pietak, J. Huadmai, G. Dias, Biomaterials 27 (2006) 1728-1734. DOI URL PMID
[7]	Y. Chen, Z. Xu, C. Smith, J. Sankar, Acta Biomater. 10 (2014) 4561-4573. DOI URL PMID
[8]	H. Ibrahim, S.N. Esfahani, B. Poorganji, D. Dean, M. Elahinia, Mater. Sci. Eng. C 70 (2017) 870-888.
[9]	R. Verma, A. Srinivasan, S.K. Nath, R. Jayaganthan, Mater. Sci. Eng. A 742 (2019) 318-333.
[10]	C. Li, H. Sun, X. Li, J. Zhang, W. Fang, Z. Tan, J. Alloys Compd. 652 (2015) 122-131.
[11]	C. Chen, J. Chen, H. Yan, B. Su, M. Song, S. Zhu, Mater. Des. 100 (2016) 58-66.
[12]	J. Zhang, Z. Kang, F. Wang, Mater. Sci. Eng. C 68 (2016) 194-197.
[13]	Z. Yu, C. Xu, J. Meng, X. Zhang, S. Kamado, Mater. Sci. Eng. A 713 (2018) 234-243.
[14]	T. Chen, Z. Chen, J. Shao, R. Wang, L. Mao, C. Liu, Mater. Sci. Eng. A 750 (2019) 31-39.
[15]	X. Xu, X. Chen, W. Du, Y. Geng, F. Pan, J. Mater. Sci. Technol. 33 (2017) 926-934.
[16]	S. Lyu, R. Zheng, W. Xiao, Y. Huang, S. Gavras, N. Hort, G. Li, C. Ma, Mater. Sci.Eng. A 760 (2019) 426-430.
[17]	S. Zhao, E. Guo, G. Cao, L. Wang, Y. Lun, Y. Feng, J. Alloys Compd. 705 (2017) 118-125.
[18]	W. Zhang, L. Tan, D. Ni, J. Chen, Y. Zhao, L. Liu, C. Shuai, K. Yang, A. Atrens, M. Zhao, J. Mater. Sci. Technol. 35 (2019) 777-783.
[19]	L. Liu, X. Chen, F. Pan, S. Gao, C. Zhao, J. Alloys Compd. 688 (2016) 537-541.
[20]	T. Bhattacharjee, T. Nakata, T.T. Sasaki, S. Kamado, K. Hono, Scr. Mater. 90-91 (2014) 37-40.
[21]	H.Y. Jeong, B. Kim, S.G. Kim, H.J. Kim, S.S. Park, Mater. Sci. Eng. A 612 (2014) 217-222.
[22]	S. Lyu, W. Xiao, R. Zheng, F. Wang, T. Hu, C. Ma, Mater. Sci. Eng. A 732 (2018) 178-185.
[23]	M. Yamasaki, T. Anan, S. Yoshimoto, Y. Kawamura, Scr. Mater. 53 (2005) 799-803.
[24]	J. Zhang, H. Li, W. Wang, H. Huang, J. Pei, H. Qu, G. Yuan, Y. Li, Acta Biomater. 69 (2018) 372-384. DOI URL PMID
[25]	M. Song, R. Zeng, Y. Ding, R.W. Li, M. Easton, I. Cole, N. Birbilis, X. Chen, J. Mater. Sci. Technol. 35 (2019) 535-544.
[26]	M.A. Amin, S.S.A. El Rehim, M.M. El-Naggar, H.T. Abdel-Fatah, J. Mater. Sci. 44 (2009) 6258-6272.
[27]	M.A. Amin, S.S.A. El Rehim, H.T. Abdel-Fatah, Corros. Sci. 51 (2009) 882-894.
[28]	S.S. Abdel-Rehim, K.F. Khaled, N.S. Abd-Elshafi, Electrochim. Acta 51 (2006) 3269-3277.
[29]	C. Cai, R. Song, E. Wen, Y. Wang, J. Li, Mater. Des. 182 (2019), 108038.
[30]	X. Lu, G. Zhao, J. Zhou, C. Zhang, L. Sun, Vacuum 157 (2018) 180-191.
[31]	L. Liu, X. Chen, F. Pan, A. Tang, X. Wang, J. Liu, S. Gao, Mater. Sci. Eng. A 669 (2016) 259-268.
[32]	Y. Chen, L. Zhang, W. Liu, G. Wu, W. Ding, Mater. Des. 95 (2016) 398-409.
[33]	H. Xu, J. Fan, H. Chen, R. Schmid-Fetzer, F. Zhang, Y. Wang, Q. Gao, T. Zhou, J. Alloys Compd. 603 (2014) 100-110.
[34]	T.Y. Kwak, W.J. Kim, J. Mater. Sci. Technol. 35 (2019) 181-191.
[35]	X. Heng, Y. Zhang, W. Rong, Y. Wu, L. Peng, Mater. Des. 169 (2019), 107666.
[36]	H.S. Jiang, X.G. Qiao, C. Xu, M.Y. Zheng, K. Wu, S. Kamado, Mater. Des. 108 (2016) 391-399.
[37]	W. Li, K. Deng, X. Zhang, K. Nie, F. Xu, Mater. Sci. Eng. A 677 (2016) 367-375.
[38]	H. Yu, Y.M. Kim, B.S. You, H.S. Yu, S.H. Park, Mater. Sci. Eng. A 559 (2013) 798-807. DOI URL
[39]	K. Oh-ishi, C.L. Mendis, T. Homma, S. Kamado, T. Ohkubo, K. Hono, Acta Mater. 57 (2009) 5593-5604. DOI URL
[40]	T.Y. Kwak, W.J. Kim, J. Alloys Compd. 770 (2019) 589-599. DOI URL
[41]	D.H. Kang, D. Kim, S. Kim, G.T. Bae, K.H. Kim, N.J. Kim, Scr. Mater. 61 (2009) 768-771. DOI URL
[42]	E. Zhang, D. Yin, L. Xu, L. Yang, K. Yang, Mater. Sci. Eng. C 29 (2009) 987-993. DOI URL
[43]	L. Xiao, G. Yang, J. Chen, S. Luo, J. Li, W. Jie, Mater. Sci. Eng. A 744 (2019) 277-289. DOI URL
[44]	X. Chen, L. Liu, J. Liu, F. Pan, Acta Metall. Sin.-Engl. 28 (2015) 492-498. DOI URL
[45]	Y. Zhou, Y. Li, D. Luo, Y. Ding, P. Hodgson, Mater. Sci. Eng. C 49 (2015) 93-100. DOI URL
[46]	B. Wang, S. Guan, J. Wang, L. Wang, S. Zhu, Mater. Sci. Eng. B 176 (2011) 1673-1678. DOI URL
[47]	L.B. Tong, M.Y. Zheng, S.W. Xu, S. Kamado, Y.Z. Du, X.S. Hu, K. Wu, W.M. Gan, H.G. Brokmeier, G.J. Wang, X.Y. Lv, Mater. Sci. Eng. A 528 (2011) 3741-3747. DOI URL
[48]	R. Hou, N. Scharnagl, R. Willumeit-Römer, F. Feyerabend, Acta Biomater. 98 (2019) 256-268. URL PMID
[49]	S.E. Harandi, P.C. Banerjee, C.D. Easton, R.K. Singh Raman, Mater. Sci. Eng. C 80 (2017) 335-345. DOI URL
[50]	H. Li, S. Pang, Y. Liu, L. Sun, P.K. Liaw, T. Zhang, Mater. Des. 67 (2015) 9-19. DOI URL
[51]	H.R.B. Rad, M.H. Idris, M.R.A. Kadir, S. Farahany, Mater. Des. 33 (2012) 88-97. DOI URL
[52]	H.R. Bakhsheshi-Rad, M. Abdellahi, E. Hamzah, A.F. Ismail, M. Bahmanpour, J. Alloys Compd. 687 (2016) 630-642.
[53]	S. Izumi, M. Yamasaki, Y. Kawamura, Corros. Sci. 51 (2009) 395-402.
[54]	M. Ge, J. Xiang, L. Yang, J.T. Wang, Surf. Coat. Technol. 310 (2017) 157-165.
[55]	A. Zomorodian, M.P. Garcia, T. Moura E Silva, J.C.S. Fernandes, M.H. Fernandes, M.F. Montemor, Acta Biomater. 9 (2013) 8660-8670. URL PMID
[56]	A. López-Ortega, J.L. Arana, E. Rodríguez, R. Bayón, Corros. Sci. 143 (2018) 258-280.
[57]	Y. Xin, T. Hu, P.K. Chu, Corros. Sci. 53 (2011) 1522-1528.
[58]	C. Liu, P. Liu, Z. Huang, Q. Yan, R. Guo, D. Li, G. Jiang, D. Shen, Surf. Coat. Technol. 286 (2016) 223-230. DOI URL
[59]	W. Jin, G. Wang, Z. Lin, H. Feng, W. Li, X. Peng, A.M. Qasim, P.K. Chu, Corros. Sci. 114 (2017) 45-56.