1. Fig. 1 Optical metallography of as-cast etched Mg-X alloys.
(a) Mg5Gd
(b) Mg0.3Ca
(c) Mg6Al
(d) Mg1Mn
(e) Mg5Sn
(f) Mg0.1Sr
(g) Mg0.6Nd
(h) Mg0.7La
(i) Mg0.9Ce
(j) Mg0.1Zr
(k) Mg0.3Si
Fig. 1 Optical metallography of as-cast etched Mg-X alloys.
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2. (a) Mg5Gd
(b) Mg0.3Ca
(c) Mg6Al
(d) Mg1Mn
(e) Mg5Sn
(f) Mg0.1Sr
(g) Mg0.6Nd
(h) Mg0.7La
(i) Mg0.9Ce
(j) Mg0.1Zr
(k) Mg0.3Si
Fig. 2 Typical surface appearance of as-cast etched Mg-X alloys as revealed by SEM.
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3. Fig. 3 Optical metallography of hot-rolled etched Mg-X alloys.
(a) Mg5Gd
(b) Mg0.3Ca
(c) Mg6Al
(d) Mg1Mn
(e) Mg5Sn
(f) Mg0.1Sr
(g) Mg0.6Nd
(h) Mg0.7La
(i) Mg0.9Ce
(j) Mg0.1Zr
(k) Mg0.3Si
Fig. 3 Optical metallography of hot-rolled etched Mg-X alloys.
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4. (a) Mg5Gd
(b) Mg0.3Ca
(c) Mg6Al
(d) Mg1Mn
(e) Mg5Sn
(f) Mg0.1Sr
(g) Mg0.6Nd
(h) Mg0.7La
(i) Mg0.9Ce
(j) Mg0.1Zr
(k) Mg0.3Si
Fig. 4 Typical surface appearance of hot-rolled etched Mg-X as revealed by SEM.
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5. Fig. 5a Hydrogen evolution volume during immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days at 24 ± 1 ℃ for hot-rolled Mg5Gd, Mg0.3Ca, Mg6Al, Mg1Mn, Mg5Sn and Mg0.1Sr alloys.
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6. Fig. 5b Hydrogen evolution volume during immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days at 24 ± 1 ℃ for hot-rolled Mg0.6Nd, Mg0.7La, Mg0.9Ce, Mg0.1Zr and Mg0.3Si alloys.
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7. Fig. 6a Corrosion rate PH during immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days at 24 ± 1℃ for hot-rolled Mg5Gd, Mg0.3Ca, Mg6Al, Mg1Mn, Mg5Sn and Mg0.1Sr alloys.
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8. Fig. 6b Corrosion rate PH during immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days at 24 ± 1℃ for hot-rolled Mg0.6Nd, Mg0.7La, Mg0.9Ce, Mg0.1Zr and Mg0.3Si alloys.
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9. Fig. 7 Comparison of the average corrosion rates evaluated from hydrogen evolution and weight loss during immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days at 24 ± 1℃ for hot-rolled Mg-X alloys.
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10. Fig. 8 Comparison of the corrosion rate evaluated from weight loss during immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days at 24 ± 1℃ for as-cast, hot-rolled and solution-heat-treated Mg-X alloys: Mg5Gd, Mg0.3Ca, Mg6Al, Mg1Mn, Mg5Sn, Mg0.1Sr, Mg0.6Nd, Mg0.7La, Mg0.9Ce, Mg0.1Zr and Mg0.3Si.
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11. Current Density (A cm-2) Potential, E, (V, Ag/AgCl/Sat.KCl)
Fig. 9a Cathodic polarisation curves measured after 24 hours immersion in the 3.5% NaCl solution saturated with Mg(OH)2 at the open circuit potential (OCP) at 24 ± 1 ℃ for hot-rolled Mg5Gd, Mg0.3Ca, Mg6Al, Mg1Mn, Mg5Sn and Mg0.1Sr alloys.
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12. Current Density (A cm-2) Potential, E, (V, Ag/AgCl/Sat.KCl)
Fig. 9b Cathodic polarisation measured after 24 hours immersion in the 3.5% NaCl solution saturated with Mg(OH)2 at the open circuit potential (OCP) at 24 ± 1 ℃ for hot-rolled Mg0.6Nd, Mg0.7La, Mg0.9Ce, Mg0.1Zr and Mg0.3Si alloys.
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13. (a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
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14. (k)
Fig. 10 Typical overview surface appearance after immersion testing at the open circuit potential (OCP) in the 3.5% NaCl solution saturated with Mg(OH)2 for 7 days for Mg-X alloys: (a) Mg5Gd, (b) Mg0.3Ca, (c) Mg6Al, (d) Mg1Mn, (e) Mg5Sn, (f) Mg0.1Sr, (g) Mg0.6Nd, (h) Mg0.7La, (i) Mg0.9Ce, (j)Mg0.1Zr and (k)Mg0.3Si. Typical views are presented for each Mg alloy in the following conditions: as-cast (the first image), hot-rolled (the second image), and solution-heat-treated (the third image).
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15. 2mm
(a)
(b)
(c)
Fig. 11 Surface appearance after the immersion test for hot-rolled Mg5Gd (a) optical image (OP); (b) back scattered electron (BSE) image, (c) secondary electron (SE) image.
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16. 2mm
(a)
(b)
(c)
Fig. 12 Surface appearance after the immersion test for hot-rolled Mg0.3Ca: (a) OP; (b) SE; (c) SE.
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17. 2mm
(a)
(b)
(c)
Fig. 13 Surface appearance after the immersion test for hot-rolled Mg6Al: (a) OP; (b) SE; (c) SE.
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18. 2mm
(a)
(b)
(c)
Fig. 14 Surface appearance after the immersion test for hot-rolled Mg1Mn: (a) OP; (b) SE; (c) SE.
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19. 2mm
(a)
(b)
Fig. 15 Surface appearance after the immersion test for hot-rolled Mg5Sn: (a) OP; (b) SE.
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20. 2mm
(a)
(b)
(c)
Fig. 16 Surface appearance after the immersion test for hot-rolled Mg0.1Sr: (a) OP; (b) SE; (c) SE.
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21. 2mm
(a)
(b)
(c)
Fig. 17 Surface appearance after the immersion test for hot-rolled Mg0.6Nd: (a) OP; (b) SE; (c) SE.
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22. 2mm
(a)
(b)
(c)
Fig. 18 Surface appearance after the immersion test for hot-rolled Mg0.7La: (a) OP; (b) SE; (c) SE.
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23. 2mm
(a)
(b)
(c)
Fig. 19 Surface appearance after the immersion test for hot-rolled Mg0.9Ce: (a) OP; (b) SE; (c) SE.
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24. 2mm
(a)
(b)
(c)
Fig. 20 Surface appearance after the immersion test for hot-rolled Mg0.1Zr: (a) OP; (b) SE; (c) SE.
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25. 2mm
(a)
(b)
(c)
Fig. 21 Surface appearance after the immersion test for hot-rolled Mg0.3Si: (a) OP; (b) SE; (c) SE.
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