Biodegradable Zn−1wt.%Mg(−0.5wt.%Mn) Alloys: Influence of Solidification Microstructure on Their Corrosion Behavior

Round 1

Reviewer 1 Report

This submission is well written and will be of interest to those involved in development of biomedical devices. This reviewer has two comments that the authors should address prior to final acceptance.

1. The optical micrographs and SEM images should be presented in two separate figures. Overlaying the images is confusing and unnecessary. Also, labeling and micron markers are difficult to read in this and subsequent microstructure data and should be in a larger font size.

2. In the conclusions it is not always clear what the authors are seeking in the way of corrosion control. Presumably, predictable and controlled corrosion rates are of interest depending on the circumstances confronted in medical applications. Perhaps a statement to this effect is in order.

Author Response

1. The optical micrographs and SEM images should be presented in two separate figures. Overlaying the images is confusing and unnecessary. Also, labeling and micron markers are difficult to read in this and subsequent microstructure data and should be in a larger font size.

Thanks for the comment. Figure 2 has been updated for a better understanding of the morphological characteristics of the analyzed alloys.

 

2. In the conclusions it is not always clear what the authors are seeking in the way of corrosion control. Presumably, predictable and controlled corrosion rates are of interest depending on the circumstances confronted in medical applications. Perhaps a statement to this effect is in order.

Thanks for the comment. A new sentence has been added to the conclusion:

The addition of 0.5 wt.% Mn to the Zn-1Mg alloy significantly increased its CRy value. This means that the alloy will degrade more rapidly in a physiological environment. This is a desirable property for bioabsorbable biomaterials, as it allows for more precise control over the time period over which the material is resorbed by the body. For example, an implant made from this alloy could be designed to degrade over a period of months or years, depending on the specific needs of the patient.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript, titled "Biodegradable Zn-1wt.%Mg(-0.5wt.%Mn) Alloys: Influence of Solidification Microstructure on their Corrosion Behavior" by Talita Vida et al., describes a study investigating the effects of the microstructural length scale on corrosion behavior. By studying Zn-Mg and Zn-Mg-Mn alloys which solidificated with different cooling rates, the authors compared the electrochemical corrosion resistance and corrosion rate of the refined microstructure with the relatively coarse microstructure using Electrochemical impedance spectroscopy and potentiodynamic polarization tests. The effect of Mn was also discussed, leading to some interesting conclusions. Overall, the manuscript is well-presented, particularly in the discussion section. However, there are some typos that need to be addressed before acceptance.

1.     Please recheck the units in the paper and ensure their uniformity. For example, in line 177, the unit of cooling rate is given as C/s, but at 208, it is mentioned as K/s.

2.     In lines 213 and 214, "The Nyquist plots are presented in Figure 3a, while the Bode and Bode-phase diagrams are displayed in Figure 3b." The figure numbers seem to be incorrect based on my understanding. It should be corrected as follows: "The Nyquist plots are presented in Figure 3a and 3b, while the Bode and Bode-phase diagrams are displayed in Figure 3c and 3d."

3.     Figure 2: The scales of each inserted figure are too small, which might cause some misunderstanding. Since the scales are different, please enlarge the font or emphasize them.

 

4.     Equation (2) has a duplicate error. Please correct it.

Author Response

1. Please recheck the units in the paper and ensure their uniformity. For example, in line 177, the unit of cooling rate is given as C/s, but at 208, it is mentioned as K/s.

Thanks for the comment. This information has been updated throughout the text.

 

2. In lines 213 and 214, "The Nyquist plots are presented in Figure 3a, while the Bode and Bode-phase diagrams are displayed in Figure 3b." The figure numbers seem to be incorrect based on my understanding. It should be corrected as follows: "The Nyquist plots are presented in Figure 3a and 3b, while the Bode and Bode-phase diagrams are displayed in Figure 3c and 3d."

Thanks for the comment. The text has been updated.

 

3. Figure 2: The scales of each inserted figure are too small, which might cause some misunderstanding. Since the scales are different, please enlarge the font or emphasize them.

Thanks for the comment. Figure 2 has been updated for a better understanding of the morphological characteristics of the analyzed alloys.

 

4. Equation (2) has a duplicate error. Please correct it.

Thanks for the comment. Equation 2 has been updated.

Author Response File: Author Response.pdf

Reviewer 3 Report

 It is a well-written and clear manuscript on corrosion behavior of two zinc alloys that can be used for bio-applications. There are very small changes which might improve the quality of the manuscript:

1- Introduction is a bit lengthy, which makes it difficult to find understand the aim of this study? Probably summarizing the middle paragraphs can be helpful. ( it is a personal opinion, and there is no need to make any changes) 

2-it would help, if Figure 2 was arranged differently. for example, removing the information line from the insets, and put the SEM images. Also, mark the magnified area.

3-The differences in samples microstructures are quantified in line 206. Showing the grain size ( a scattered graph) will help the reader to see Low/High values. 

Author Response

1- Introduction is a bit lengthy, which makes it difficult to find understand the aim of this study? Probably summarizing the middle paragraphs can be helpful. ( it is a personal opinion, and there is no need to make any changes)

Thanks for the sugestion.

 

2-it would help, if Figure 2 was arranged differently. for example, removing the information line from the insets, and put the SEM images. Also, mark the magnified area.

Thanks for the comment. Figure 2 has been updated for a better understanding of the morphological characteristics of the analyzed alloys.

 

3-The differences in samples microstructures are quantified in line 206. Showing the grain size ( a scattered graph) will help the reader to see Low/High values.

Thanks for the sugestion. A text was inserted suggesting the reading of previous publications with this more detailed information.

“More information about dendrite and eutectic spacings, of Zn-1Mg and Zn-1Mg-0.5Mn, can be seen in previous research [26].”

 

Author Response File: Author Response.pdf