Multicomponent Fe-Based Bulk Metallic Glasses with Excellent Corrosion and Wear Resistances
, Xu Ma 3,4, Dongmei Zhao 6 and Jiangtong Yu 1Round 1
Reviewer 1 Report
It is a correct scientific work about the corrosion and wear resistances of some multicomponent Fe-based bulk metallic glasses. Nevertheless, this manuscript is a summary of results. The discussion should be improved taken into account the role of each element. Thus, I recommend a major revision.
There are a lot of articles of Fe-based bulk metallic glasses without rare-earth elements. I think that the title should began: Multicomponent Fe-based bulk metallic glasses …. . Due to the content of each element there are multicomponent, never high entropy alloys.
Introduction: This section needs to be improved. There are articles suggesting the role of different elements in the formation of the metallic glasses and also about the influence of these elements in the corrosion and wear resistances.
How the authors calculate the critical diameter (5.5 mm)? How the authors determine this parameter in the diffraction patterns? I also recommend the addition of a reference.
DSC scans: There are several exothermic processes linked to complex crystallization in multicomponent alloys. I recommend at least one XRD diffraction pattern at high temperature to check the produced phases.
The alloys have a good corrosion resistance. Nevertheless, figure 3 shows the corrosion of these alloys. The authors should improve the discussion by comparing with the scientific literature of Fe-based metallic glasses, taking also account the role of each element.
Microhardness and coefficient of friction: How many measurements? Thus, statistical deviation should be given in tables and figures.
Likewise, I recommend to clarify the scale bars in figure 6 (in a similar way to those of figure 3).
References: The authors should unify the references format taken into account the guidelines of this journal (Metals).
Author Response
Reviewer #1 (Comments to the Author):
It is a correct scientific work about the corrosion and wear resistances of some multicomponent Fe-based bulk metallic glasses. Nevertheless, this manuscript is a summary of results. The discussion should be improved taken into account the role of each element. Thus, I recommend a major revision.
1. There are a lot of articles of Fe-based bulk metallic glasses without rare-earth elements. I think that the title should began: Multicomponent Fe-based bulk metallic glasses …. . Due to the content of each element there are multicomponent, never high entropy alloys.
Ans.: We would like to accept the reviewer’s suggestion and the title of the revised manuscript is changed to “Multicomponent Fe-based bulk metallic glasses with excellent corrosion and wear resistances”.
2. Introduction: This section needs to be improved. There are articles suggesting the role of different elements in the formation of the metallic glasses and also about the influence of these elements in the corrosion and wear resistances.
Ans.: Thanks for the reviewer’s suggestion and the section of Introduction has been extensively modified in the revised manuscript. Generally, the higher the Cr content, the better the corrosion resistance of Fe-based BMGs. However, when the Cr content is more than 15 at.%, further increasing the Cr content cannot significantly improve the corrosion resistance of the Fe-based BMGs, but increase the material cost. The effect of Mo on the protective ability of passivation layer is weaker than that of Cr. But the Mo can promote the enrichment of Cr in the passive film, thereby enhancing the corrosion and pitting resistance of Cr-containing Fe-based BMGs, while the excess addition of Mo (5-10 at.%) became detrimental for the corrosion resistance of Fe-based BMGs [Li, S., et al., Development of Fe-based bulk metallic glasses as potential biomaterials. Materials Science and Engineering: C 52(2015)235-241]. Based on the above consideration, the alloy with the composition of Fe59Cr15Mo6Si2B4P10C4 is selected in this work. Additionally, it was found that the substitution of Fe by the similar element of Ni or Co can produce positive effects on GFA, mechanical and magnetic properties of Fe -based BMGs. For example, The substitution of 20 at.% Ni for Fe of Fe80P13C7 BMG results in the increase of the critical diameter (Dc) for fully glass formation from 2.0 mm to 2.3 mm, and the significant increase of room-temper compressive plastic strain from 1.1% to 11.2% [Ma, X.H., et al., Quaternary magnetic FeNiPC bulk metallic glasses with large plasticity. Journal of Alloys and Compounds, 577(2013)345-350.]. The room-temperature compressive plasticity of Fe80P13C7 BMG improves from 1.1% to 3.0% and the saturation magnetization increases from 1.45 T to 1.55 T through the replacement of 10 at.% Fe by Co [Effects of Co substitution for Fe on the glass forming ability and properties of Fe80P13C7 bulk metallic glasses. Intermetallics, 51(2014)53-58]. Therefore, the effect of the replacement of 5 at.% Fe by Co/Ni on the properties of the Fe59Cr15Mo6Si2B4P10C4 BMG has been studied.
3. How the authors calculate the critical diameter (5.5 mm)? How the authors determine this parameter in the diffraction patterns? I also recommend the addition of a reference.
Ans.: The critical diameter for fully glass formation of the alloys has been determined by the experimental method in this work. The rod alloy samples with different diameters were prepared by J-quenched technique and them these sample are identified whether they are fully amorphous structure by XRD analysis. The above method is widely used by the researchers in the field of BMGs. Sorry, we do not quite understand the reviewers' comment and so do not know what references should be cited here.
4. DSC scans: There are several exothermic processes linked to complex crystallization in multicomponent alloys. I recommend at least one XRD diffraction pattern at high temperature to check the produced phases.
Ans.: We understand the reviewer’s comment and the determination of the phases precipitated from amorphous alloy in the heating process is of significance to understand the glass formation of the alloy. But the purpose of this study is aim to develop new Fe-based BMGs for coating materials. So we mainly focuses on their corrosion and wear properties and the crystallization mechanism of the present Fe-based BMGs don’t involve in this work.
5. The alloys have a good corrosion resistance. Nevertheless, figure 3 shows the corrosion of these alloys. The authors should improve the discussion by comparing with the scientific literature of Fe-based metallic glasses, taking also account the role of each element.
Ans.: The reviewer’s comment is appropriate and the corresponding discussion has been added in Page 5 of the revised manuscript. It is worth noting that the corrosion resistance of the Fe59 BMG is better than that of most reported Fe-based BMGs, of which the Icorr is usually on the order of 10-6 ~ 10-7 A/cm2. For example, it is reported that a Fe36Cr23Mo10W8C15B6Y2 BMG possesses good corrosion resistance with a Icorr of 6.16×10-7 A·cm-2 and Ecorr of -0.275 V [X Zhang, et al., Intermetallics 2022, 143, 107485]. Compared with this Fe-based BMG, the Fe59 BMG exhibits lower Icorr but contains less Cr and Mo. Such the result may be related to the metalloid elements in the alloys, which can also significantly influence the corrosion properties of Fe-based BMGs [H.X. Li, et al., Prog. Mate. Sci. 103(2019)235–318]. For example, Si could improve the passivation ability and corrosion resistance of Fe-based BMGs, which can be attributed to the formation of dense and stable passive film rich in Si- and Cr- oxides [S Zheng, et al., J non-cryst. Solids 493(2018)33–40]. The Fe43Cr16Mo16C10B5P10 BMGs exhibits a wide passive region, indicating the higher corrosion resistance in comparison with that of the P-free metallic glass [S.J. Pang, et al. Acta Mater. 50(2002)489–497]. Additionally, the underlying mechanisms of the excellent corrosion of the present Fe-based BMGs is explored by XPS analysis in this work.
6. Microhardness and coefficient of friction: How many measurements? Thus, statistical deviation should be given in tables and figures.
Ans.: Thanks for the reviewer’s suggestion. The average of ten measurement values was taken as the final value of hardness for each specimen. The friction coefficient of the specimens was measured for three times. And the corresponding statement has been added in the section of Experiment and the uncertainty of the experimental data has been given in the corresponding tables and figures in the revised manuscript.
7. Likewise, I recommend to clarify the scale bars in figure 6 (in a similar way to those of figure 3).
Ans.: Thanks for the reviewer’s suggestion and the Fig. 6 have been redrawn in a manner similar to Fig. 3.
8. References: The authors should unify the references format taken into account the guidelines of this journal (Metals).
Ans.: The reference format has been revised thoroughly according to journal requirements.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In my opinion the paper can be published in Metals. However some mandatory changes have to be made:
- extensive english revision of the text. there are many Grammar mistakes.
- Wear rate is obtained by equation 1. However, the values of density and how were they determined is not explained.
- In line 249, Fig 5 instead of Fig 6.
- Ref 17 must be corrected.
Author Response
Reviewer #2:
In my opinion the paper can be published in Metals. However some mandatory changes have to be made:
1. Extensive english revision of the text. there are many Grammar mistakes.
Ans.: Thanks for the reviewer’s comment. We have carefully checked the manuscript throughout to correct the potential typing and English grammatical errors. We hope that the revised manuscript could satisfy the reviewer’s requirement.
2. Wear rate is obtained by equation 1. However, the values of density and how were they determined is not explained.
Ans.: Sorry for our carelessness. The density of the specimens is measured by density testing equipment (AccuPyc-1340). The corresponding statement has been added in the section of Experiment and the data of the density are listed in Table 3 of the revised manuscript.
3. In line 249, Fig 5 instead of Fig 6.
Ans.: Sorry for our carelessness and the corresponding modification has been made in the revised manuscript.
4. Ref 17 must be corrected.
Ans.: Sorry for our carelessness and this reference has been modified in the revised manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript presents very interesting and relevant results. However, some minor revison must be performed.
- Please add some information about the EIS tests in the "Materials and Methods" topic. Besides, also add infomation about the solution used to perform the electrochemical tests.
- Please explain the Electric Equivalent Circuit fitted to the EIS results. Why the components correspond to the charge transfer instead of the oxide layer, for example?
- Please improve the micrographs (Fig 6). The magnification bars are too small.
Author Response
Reviewer #3:
1. Please add some information about the EIS tests in the "Materials and Methods" topic. Besides, also add information about the solution used to perform the electrochemical tests.
Ans.: According to the reviewer’s suggestion, the related information about electrochemical tests have been added in the section of "Materials and Methods" of the revised manuscript.
2. Please explain the Electric Equivalent Circuit fitted to the EIS results. Why the components correspond to the charge transfer instead of the oxide layer, for example?
Ans.: Thanks for the reviewer’s comment. Generally speaking, the total impedance of an electrochemical process can be abstracted into a circuit composed of three electrical elements: internal resistance (Rs), electric double-layer capacitance (Qt), Faraday impedance (Zf). Among them, internal resistance (internal resistance of electrolyte and electrode). Electric double-layer capacitance (it comes from the inactive ions in the electrolyte), there is no chemical reaction and only changes the charge distribution. Faraday impedance (from the active ions in the electrolyte), there is redox reaction and charge transfer. The Faraday process can be further divided into two processes: charge transfer and material transfer. In order to further determine the electrical components contained in Faraday impedance，equivalent circuits those proposed to fit the EIS data by ZSimpWin software are revealed in Fig.2(b). As for the components, an equivalent circuit as shown in Fig. 2(b) is established, which consists of the resistance of electrolyte solution Rs, the resistance of the samples Rt, the capacitance of the samples Qt, the resistance of charge transfer Ru, and the capacitance of the double layer Qu. Therefore, based on the fitting components, we think that the process should correspond to charge transfer. Of course, the interpretation of EIS is a complicated and huge task. Here we only used EIS spectrum to simply evaluate the corrosion resistance of the alloys, and did not make an in-depth analysis of EIS spectrum, which is out of the scope of this study.
3. Please improve the micrographs (Fig 6). The magnification bars are too small.
Ans.: According to the reviewer’s suggestion, the magnification bars in Fig. 6 have been enlarged in the revised manuscript.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The manuscript quality has been improved by taking into account the comments of the referees.
The references format should be updated following the guidelines of this journal
Author Response
The references format should be updated following the guidelines of this journal.
Ans.: We have checked carefully the formation of the references in the manuscript and think that the present format of the references meets the requirements of the journal of “Metals”. So we wonder what is wrong with the present formation of the references.
Reviewer 2 Report
The authors have reviewed the paper and corrected some of the flaws found in the previous version.
In tabe 3 they added the density values and the uncertainity of the different magnitudes. However, I have two comments on this:
- The density of the BMGs, with small variations of 5 % in composition, show large changes in density. This seems strange to me. Normally, so small variations gives changes in density of about 2%. In this case, the authors report changes of up to 12%. Have you estimated a theoretical density of the alloys? It should give an idea of the expected values.
- The reported uncertainties and significant figures of experimental values of microhardness and COF given in table 3 are not correct. Authors should (must) review lab textbooks like “Taylor, J. R. (1997). An introduction to error analysis: The study of uncertainties in physical measurements. Mill Valley, Calif: University Science Books.2n edtition”
Author Response
1. The density of the BMGs, with small variations of 5 % in composition, show large changes in density. This seems strange to me. Normally, so small variations gives changes in density of about 2%. In this case, the authors report changes of up to 12%. Have you estimated a theoretical density of the alloys? It should give an idea of the expected values.
Ans.: Thanks for the reviewer’s comment and there are really some problems with the data of the density. We have re-measured the density of the samples and new results of the density and the re-calculated wear rate have been updated in Table 3 and Figure 5.
2. The reported uncertainties and significant figures of experimental values of microhardness and COF given in table 3 are not correct. Authors should (must) review lab textbooks like “Taylor, J. R. (1997). An introduction to error analysis: The study of uncertainties in physical measurements. Mill Valley, Calif: University Science Books. 2n edtition”
Ans.: Thanks for the reviewer’s comment. For microhardness, the average of ten measurement values was taken as the final hardness value for each specimen, and the uncertainties was determined by experimental standard deviation of arithmetic mean , which is calculated by the equation of , where xi is the i-th measurement value, is the average value and n is the measurement number. In general, the 1 ~ 2 significant figures should be reserved for the uncertainty, and thus we revise the significant figures of the uncertainty of microhardness in Table 3. We wonder whether this is the revision that the reviewer wants. The uncertainty of the COF was given by the software with the test equipment, and we don’t know what is wrong with them.
Round 3
Reviewer 2 Report
The new values of density seem more consistent to me.
Author Response
The new values of density seem more consistent to me.
Ans.: Thanks for the reviewer's comment, but we wonder what we should do next.
