Tribocorrosion Behavior of CoCrNi Medium Entropy Alloy in Simulated Seawater
Round 1
Reviewer 1 Report
I would like to congratulate the authors for their successful work. Nice work. In my opinion, it is acceptable as it is.
Author Response
Thank you very much for your recognition of our work, which makes us very glad.Wishing you good health and happiness in your family during the Chinese New Year
Reviewer 2 Report
The paper entitled “Tribocorrosion Behaviour of CoCrNi Medium Entropy Alloy in Simulated Seawater” investigated the tribocorrosion behaviour and mechanism of CoCrNi in seawater and made some tribological comparisons with Inconel600 and 316L stainless steel alloys. The paper has scientific interest and originality in its technical content to merit publication and the authors have cited the relevant literature. However, sometimes the manuscript is a little bit confusing and poorly described.
The materials used in this work should be identified in a more detail, namely in terms of chemical composition, microstructure and mechanical properties, at least in terms of hardness.
Line 12 and line 71:
The authors began by saying in the abstract that “the tribocorrosion behaviour of CoCrNi was investigated on a pin-on-disc tribometer”. Later, at the last paragraph of the introduction they stated that “unidirectional sliding wear tests were carried out” and they performed reciprocating sliding wear test. The authors must correct this.
Line 83:
Why didn’t the authors use diamond suspension to achieve a mirror finishing surface and does not characterize in terms of roughness parameters (at least Ra) the different specimens? This is important as imperfections can be preferred points for the appearance of pitting.
Line 106-110:
Point (iii) is a little bit confusing. Basically, is this that the authors want to perform.
The CoCrNi specimen was polarized to study the influence of different applied potentials on the tribological behaviour (friction and wear).
Line 159-160:
What is the main reason why 316L stainless steel alloy shows a second passivation plateau only under static conditions? Authors must explain this behavior.
Line 204-205:
The authors stated that “By comparing Figs. 4a and 4b, it can be seen that as the applied potential changes from -0.2V to 0.1V, the total mass loss of CoCrNi increases by about 3 times”. However, looking to the graphic we do not have this perception. If possible, the authors should use the same scale for the volume of the material loss.
Line 214-217:
During the results and discussion, readers are surprised by authors who propose to investigate further conditions (-0.8V, -0.42V, 0.2V, etc…). This must be explained in some way in the materials and methods section that is confusing and poorly described, especially the point (iii).
Line 207:
Fig. 3a does not presented any arrow.
Fig.4:
The legend of Fig. 4 should say instead of “friction coefficient” (steady state coefficient of friction) or (average coefficient of friction).
Fig. 5:
It would be interesting to measure friction at potentials between 03 to 0.4 V to observe the friction behaviour in transpassivation conditions. Why did the authors stop at 0.25 V?
Fig.6:
Legends from individual 2D profiles are not visible enough. Change the general legend at Fig. 6 in order to include also the 2D profiles…e.g. 3D and 2D profiles…
Table 2:
- If the units (V) come in the first column, remove in the following columns
- Changed “depth of the wear” by (depth of the wear track) or (wear depth)
- Changed “width of the wear” by (width of the wear track) or (wear width)
Subchapter 3.3:
The authors performed a deep SEM analysis of the CoCrNi worn surfaces to understand and compare the wear mechanisms for different applied potentials. However, they forgot to do the same for the surfaces of the Inconel 600 and 316L and justified the results presented in Figure 4. The authors should complete this analysis, if possible and/or comment on this.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 3 Report
Dear authors,
I enjoyed reading the manuscript because the paper is well-described, and the results are clearly demonstrated. ​ The authors have made a good synthesis of the literature that provides an overview of the research evolution in this area.
This manuscript, entitled „Tribocorrosion Behavior of CoCrNi Medium Entropy Alloy in Simulated Seawater” is relevant to the scope of this journal.
This is an interesting study, with many characterization techniques used, that can provide interesting information to specialists.
Therefore, the article can be recommended for publication only after minor revision according to the following suggestions:
1.The authors must specify very clearly which sizes are calculated and presented in Table 3.
2.In Figure 6 the images are not very clear. They should be replaced with a better resolution.
3.Beware of double numbering from references.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors' effort to improve the manuscript was appreciated. However, some problems remain to be fixed, especially so that the results can be compared with those of other authors and so this paper proves to be useful for the scientific community.
Tribological behavior and corrosion resistance are greatly affected by surface properties. In addition to the chemical composition, production, processing and heat treatment routines can determine significant variations in mechanical behavior, namely in hardness. The identification of the polishing routine is not an adequate way to characterize the surface roughness.
Therefore the mechanical properties of materials must be included, at least the hardness and the surface roughness must be indicated.
Author Response
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Author Response File: Author Response.pdf
