(c) 24 h; WZ73-1.5 vol% SiC after (d) 1; (e) 12 and (f) 24 h; WZ73-2.5 vol% SiC after (g) 1; (h) 12 and (i) 24 h. Figure 8. XRD patterns of the surface corrosion layers in WZ73 and MMCs after immersing in 1 wt % NaCl solution for (a) 12 h and (b) 24 h. It has been reported that the corrosion reactions of Mg alloys immersed in a neutral aqueous solution proceed by the following reactions [33–35]: Mg → Mg2+ + 2e− (2) 2H2O + 2e− → H2+ + 2OH− (3) Mg2+ +2OH− → Mg(OH)2 (4) Figure 7. Surface morphology of WZ73 after immersing in 1 wt % NaCl solution for (a) 1; (b) 12 and (c) 24 h; WZ73-1.5 vol % SiC after (d) 1; (e) 12 and (f) 24 h; WZ73-2.5 vol % SiC after (g) 1; (h) 12 and (i) 24 h. Metals 2018, 8, x FOR PEER REVIEW 10 of 16 Figure 7. Surface morphology of WZ73 after immersing in 1 wt % NaCl solution for (a) 1; (b) 12 and (c) 24 h; WZ73

(c) 24 h; WZ73-1.5 vol% SiC after (d) 1; (e) 12 and (f) 24 h; WZ73-2.5 vol% SiC after (g) 1; (h) 12 and (i)
24 h.
Figure 8. XRD patterns of the surface corrosion layers in WZ73 and MMCs after immersing in 1 wt %
NaCl solution for (a) 12 h and (b) 24 h.
It has been reported that the corrosion reactions of Mg alloys immersed in a neutral aqueous
solution proceed by the following reactions [33–35]:
Mg → Mg2+ + 2e− (2)
2H2O + 2e− → H2+ + 2OH− (3)
Mg2+ +2OH− → Mg(OH)2 (4)
Figure 7. Surface morphology of WZ73 after immersing in 1 wt % NaCl solution for (a) 1; (b) 12 and
(c) 24 h; WZ73-1.5 vol % SiC after (d) 1; (e) 12 and (f) 24 h; WZ73-2.5 vol % SiC after (g) 1; (h) 12 and
(i) 24 h.
Metals 2018, 8, x FOR PEER REVIEW 10 of 16
Figure 7. Surface morphology of WZ73 after immersing in 1 wt % NaCl solution for (a) 1; (b) 12 and
(c) 24 h; WZ73