Effect of Ca Element on Microstructure and Corrosion Behavior of Single-Phase Mg–Sc Alloy
, Yanchun Zhao 2, Tingzhuang Han 4, Guangang Wang 5, Liang Wu 5 and Guangsheng Huang 5Round 1
Reviewer 1 Report
The paper “Effect of Ca element on microstructure and corrosion behavior of single-phase Mg-Sc alloy” can be published after major revision.
What is the mechanism of Sc influence on corrosion behavior in Mg-Sc alloy?
Figure 6 and the corresponding description are not informative. It is difficult to reveal noticeable differences in presented structures.
Does figure 7 present the SEM images? Please clarify.
I recommend authors perform the SEM analysis of the cross-section of the skin layer to compare the depth of crack penetration in studied alloys.
The first conclusion “the number of the second phase particles gradually increased with Ca content” is obvious according to the phase diagram and does not involve scientific novelty.
Conclusions 2 and 3 are too superficial. The quantitative characteristics, including Ca content, corrosion resistance characteristics, should be reflected in conclusions.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is focused on revealing the effect of Ca on microstructure and corrosion performance of Mg-Sc Alloy, which is an actual topic nowadays due to the high potential of Mg alloys for biomedical use. The Paper is well-organized and methods for investigation have been chosen properly. There are some flaws and revision should be performed before acceptance present paper for publishing in Metals.
p.1 row 31 “second phase”ïƒ “presence of the second phase”
p1 row 40 “beneficial to the improvement” ïƒ “beneficial for the improvement”
p1, row 40 “Scandium (Sc) element is easy to form a single-phase alloy” – need revision Sc element cannot “be formed” in the alloy.
p2, row 66: content -> amount
p2 Table 1 –values for Ca might be introduced as well.
P2, row85 size should be introduced in CI units.
P3 row 106 “test 17” -> “test” or what does “test 17” means should be explained.
P3 row 113 What is the error for average grain size?
P3 Fig.1 scale could be enlarged for the reader’s benefit. Same for Fig.7.
P4-5 section 3.2: the author may consider adding plot Ph vs time in Fig.3.
p.9 row 235 Sentence “Concluded as follow“ is grammatically incorrect.
The evolution of H2 indicates the lowest value for MS2Ca, which is in agreement with polarization curves and EIS results. How an author can explain the lowest values for MS2Ca? This is the main finding of the present research and should be properly discussed. It is recommended to perform a more detailed microstructure analysis of investigated alloys in the initial state using SEM imaging with high resolution (and even TEM). Perhaps, the corrosion performance of the alloys can be linked to microstructure features. Otherwise, the final statement “With the increase of Ca element content, the corrosion resistance of the alloy in-243 creases first and then decreases due to the microstructure of the alloys.” Doe does not have any evident support.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors responded to all comments. I recommend accepting the article in revised form.
Author Response
Thank you so much for your suggestions.
