FeSiBPNbCu Bulk Nanocrystalline Alloys with High GFA and Excellent Soft-Magnetic Properties

Round  1

Reviewer 1 Report

Dear authors,

I wish to appreciate you for your work.  The work is interesting.  The manuscript it is not correctly written and the results are not consistent. Some mistakes in the text should be corrected:

1.The phases in Fig.1 (for x=0) are not identified.

2. Where are differences for the x=1, 1.2 and 1.5 samples (Fig. 1)? It is not clear.

3. The author stated:

“According to the empirical rules of high GFA glass alloy, the addition of Nb causes the more sequential change in atomic size order as well as the generation of new atomic pairs with various larger negative heats of mixing between Nb and (Fe, Si, B, P) atomic pairs.”

Where is the references literature for this claim?

                4. How the optimum quantity of Cu (0.7 at.%) for the FeSiBP system was selected? Please, referee to literature. Please take into account data from:

·  Lu Z. P., Liu C. T.: Role of minor alloying additions in formation of bulk metallic glasses: A Review. Journal of Materials Science, 39, 2004, 3965–3974.

·  Takahara Y., Matsuda H.: Calorimetric and resistometric study on crystallization of amorphous Fe–B–Si alloys. Materials Transactions JIM, 36, 7, 1995, 903–908.

·  Kulik T.,  Horubała T.,  Matyja H.: Flash annealing nanocrystallization of Fe–Si–B–based glasses. Materials Science and Engineering A, 157, 1, 1992, 107–112.

·  Lesz S., Babilas R., Nowosielski R.: Influence of copper addition on glass forming ability, thermal stability, structure and magnetic properties of Fe–Co–based BMGs, Conference: 22nd Conference on Applied Crystallography Location: Targanice, POLAND Date: SEP 02-06, 2012 ,APPLIED CRYSTALLOGRAPHY XXII   Book Series: Solid State Phenomena, 203–204, 2013, 296–301.

·  Jia Y., Zeng S., Shan S., Zhang L., Fan C., Zhang B., Zhan Z., Liu R., Wang W.: Effect of copper addition on the glass forming ability of a Fe–Co based alloy. Journal of Alloys and Compounds, 440, 2007, 113–116.

·  Lesz S.: A study of structure and magnetic properties of low purity Fe-Co-based metallic glasses. Materials, 10, 6, 2017, 625_1-18.

·  Li R., Stoica M., Eckert J.: Effect of minor Cu addition on phase evolution and magnetic properties of {[(Fe_0.5Co_0.5)_0.75Si_0.05B_0.20]_0.96Nb_0.04}_100-xCu_x alloys. Journal of Physics: Conference Series, 144, 2009, 012042.

            5.    In  Experimental Procedures lack of information about the activation energy evaluation.

            6.    English needs improvement. For instance:

Page 1 Lines 34-38:

 “Since the Fe73.5Si13.5B9Nb3Cu1 (FINEMET) nanocrystalline alloy obtained by through crystallizing the corresponding glassy precursors was firstly reported by Yoshizawa in 1988 [1], Fe-based nanocrystalline alloys have attracted great interests, because of its excellent SMPs and extremely low core loss, and thus the low energy consumption and high efficiency [2,3].”

Pages 1-2 Lines 43-46:

“By employing a three-dimensional atom probe and a high resolution electron microscope, it was further evidenced that Cu clusters are indirectly contacting with the α-Fe(Si) nanocrystals, suggesting that the α-Fe(Si) particles heterogeneously nucleate at the site of Cu clusters [9].”

Page 2  Lines 49-50:

“However, the glass forming ability (GFA) of these nanocrystalline alloys with high Bs is much 49 low, of which the critical diameter (Dcr) of fully amorphous rods is no more than 1 mm.”

Page 2  Lines 53-56:

“Resultantly, a series of alloys have successfully been developed [10-16], 53 which can be made into thick ribbon or nanocrystalline rod-shaped samples. Recently, by logically 54 adding Cu, FeSiBPNbCu alloys with high GFA and SMPs were successfully developed by our team 55 [16].”

Page 2  Lines 64-65:

“Therefore, it is very instructive to study the effect of Nb content on the comprehensive performance in industrial production.”

 Page 2  Lines 71-73:

“(Fe0.76Si0.09B0.1P0.05)99.3−xNbxCu0.7 (x = 0-1.5) alloy ingots were melt by induction melting of pure metals of Fe (99.99 wt.%), Nb (99.9 wt.%) and Cu (99.99 wt.%), crystalline Si (99.99 wt.%) and B (99.9 wt.%) metalloids, and Fe3P (99.9 wt.%) pre-alloy in a high-purity argon atmosphere.”

I found many errors in the revised text.  I give only few examples.

Author Response

Response to Reviewer 1 Comments

Point 1: The phases in Fig.1 (for x=0) are not identified:

Response 1: Thank the reviewer for this indication. We have identified the main phases by indexing corresponding crystallization peaks in Fig.1. See page 3, line 120.

Figure 1. XRD patterns of the as-cast (Fe_0.76Si_0.09B_0.1P_0.05)_99.3−xNb_xCu_0.7 (x = 0, 0.2, 0.5, 0.8, 1.0, 1.2, 1.5) rods with different diameters.

Point2: Where are differences for the x=1, 1.2 and 1.5 samples (Fig. 1)? It is not clear.

Response 2: The critical diameter (D_cr) of amorphous rod samples containing varying amounts of niobium, as annotated in Fig. 1 is used to characterize the glass-forming ability (GFA) of the alloys. In fact, as shown in Fig.1, the XRD pattern for all the Nb-containing alloys (including x=0.2, 0.5, 0.8, 1, 1.2 and 1.5 samples), presents only a broad peak implying the formation of a single amorphous structure in the samples with D_cr. And the D_cr falls into the range of 1-2.5 mm. The GFA was significantly enhanced with minor Nb addition. However, with minor Nb addition, there is no difference in the characteristics of the XRD patterns and the amorphous structure among the Nb-containing alloys except reflecting the different GFA of the alloys.

Point3: The author stated: “According to the empirical rules of high GFA glass alloy, the addition of Nb causes the more sequential change in atomic size order as well as the generation of new atomic pairs with various larger negative heats of mixing between Nb and (Fe, Si, B, P) atomic pairs.”

Where is the references literature for this claim?

Response 3: As suggested by the reviewer, citation is needed in this statement. So, a citation of the literature has been added at the end of the sentence, listed as Ref.20 in the part of bibliography. The reference literature gives a valuable explanation for the reason in FeSiBP bulk glassy alloys. See page 3, line 108. 

Point4: How the optimum quantity of Cu (0.7 at.%) for the FeSiBP system was selected?

Response 4: According to our previous work (listed as Ref.18 in the part of bibliography) in the FeSiBPCuNb bulk amorphous system, a nanocrystalline alloy with high amorphous forming ability and excellent soft magnetic properties was obtained by looking at the role of Cu content. It was found that the maximum amorphous forming ability can be obtained when the Cu content is around 0.75 at. % and Nb content is fixed. Based on this finding, this work purposefully designed the composition of FeSiBPCuNb alloy system with the fixed Cu content of 0.7 at. % just to further explore the influence of the change in Nb content on the amorphous forming ability and soft magnetic properties of the nanocrystalline system. It is expected to obtain an amorphous nanocrystalline alloy with further improved comprehensive performance, which is confirmed by the present work. To illustrate this, we have deliberately given instructions. See page 2, lines 65-66: “Especially when 0.75 at.% Cu was introduced into FeSiBPNb alloy, the alloy after nanocrystalline treatment showed superior soft magnetic properties and high amorphous formation ability” .

Point5: In Experimental Procedures lack of information about the activation energy evaluation.

Response 5: According reviewer’ suggestion, the information about the activation energy evaluation has been added in the revised manuscript. See page 3, lines 93-95: “Based on the DSC curves of as-cast specimens at the heating rates of 0.167, 0.33, 0.5 and 0.67 K/s, the corresponding Kissinger plots of the specimens was used to calculate the activation energy (E_a).”.

Point6: English needs improvement.

Response 6: We are very sorry for our many errors in the manuscript. We have made a careful check and given improvement and corrections in the revised manuscript.

Other changes:

We have carefully checked the manuscript and made some modifications in the revised manuscript.  These changes will not influence the content and framework of the paper. And we have detailedly listed and marked them in red color in revised paper.

Modified words:

Lines 36,38,40 at page 1.

Lines 42, 44, 46-50, 82, 85 at page 2.

Lines 87, 98, 107-112, 115, 119 at page 3.

Lines 130, 134-136 at page 4.

Lines 137, 138-141, 149-150, 152-153, 155, 160-166, 168-169 at page 5.

Lines 170-176, 177-179, 185, 187-188, 190-191 at page 6.

Lines 201-203, 204-207, 209-210, 212, 216 at page 7.

Lines 226, 228, 233 at page 8.

Lines 245, 250, 252 at page 9.

Revised reference number:

Lines 62, 64, 72 at page 2.

Lines 112, 117, 119, at page 3.

Line 145 at page 4.

Lines 155, 157, 165, 185 at page 5.

Lines 189, 193 at page 6.

Lines 215, 232, 236 at page 7.

Line 243 at page 8.
   We appreciate for Editors/Reviewers’ warm work and hope that the correction will meet with approval.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors provide a paper dealing with Fe-based metallic glass ribbons with high glass forming ability and soft magnetic properties. The paper is interesting and it fits with Metals journal topics. However, some revisions are requested:

1.       The authors should avoid the use of acronyms (GFA) in the title and in the abstract. The abstract can also be less technical providing more details and stressing more the conclusions.

2.       In the introduction the authors are invited to comment more about the possible applications of metallic glass which are often limited by their brittle mechanical behavior. Specifically, a recent research field is represented by the mechanical properties of thin film metallic glasses which show interesting size effects reporting large ductility and yield strength. This size effects can be activated even for small-scale ribbons. Specifically, the authors are invited to discuss the following papers doi.org/10.1016/j.actamat.2017.03.072, 10.1038/ncomms1619 and many others. Moreover, thin films metallic glass can exhibit interesting magnetic properties making them very appealing for applications.

3.       I would like that the authors comment in a better way Figure 1. Specifically, it is strange that although the composition of the BMG change there is no change on the position of the diffraction hump which is always located around 45°. As a matter of facts the change of local order due to composition should induce also a change of the position of the diffraction hump see the following paper doi.org/10.1016/j.jallcom.2013.12.054 that worth to be commented. 

Author Response

Response to Reviewer 2 Comments

Point 1: The authors should avoid the use of acronyms (GFA) in the title and in the abstract. The abstract can also be less technical providing more details and stressing more the conclusions.


Response 1: According to the reviewer’s suggestion, we have made some modification to the abstract, which stresses more the conclusions and avoids providing more technical details. See page 1, lines16-27.

Abstract: (Fe_0.76Si_0.09B_0.1P_0.05)_99.3−xNb_xCu_0.7 (x = 0–1.5 at. %) bulk nanocrystalline alloys were prepared to investigate the alloying effects of Nb on glass forming ability, thermal stability, soft magnetic properties and crystallization behavior. It was found that the amorphous forming ability was greatly improved with the addition of minor Nb. The thermal stability of Nb-containing alloy is significantly improved because the initial crystallization temperature and crystallization activation of the primary phase were obviously improved compared with that of the Nb-free alloy. Further, the larger intervals of two-phase crystallization temperature and the significantly higher activation energy of crystallization of the second phase in the Nb-containing alloys favor the formation of a single α-Fe(Si) nanocrystalline structure. And Nb-containing alloys exhibit excellent soft magnetic properties, including high saturation magnetization of 1.42-1.49 T, low coercivity (H_c) of around 1.0 A/m and high permeability of about 18,000 at 1 kHz, which makes the alloys promising soft magnetic materials for industrial applications.

Point 2: In the introduction the authors are invited to comment more about the possible applications of metallic glass which are often limited by their brittle mechanical behavior. Specifically, a recent research field is represented by the mechanical properties of thin film metallic glasses which show interesting size effects reporting large ductility and yield strength. This size effects can be activated even for small-scale ribbons. Specifically, the authors are invited to discuss the following papers doi.org/10.1016/j.actamat.2017.03.072, 10.1038/ncomms1619 and many others. Moreover, thin films metallic glass can exhibit interesting magnetic properties making them very appealing for applications.

Response 2: The reviewer's comments are in line with the application status and development trend of metallic glass. The mechanical properties of metallic glass - intrinsic brittleness, makes it difficult to be processed and formed, which seriously limits its practical application in engineering. As the reviewer pointed out, this size effects of large ductility and yield strength can be activated for nanoscale thin film metallic glasses and even for micronscale ribbon ones, which exhibit excellent magnetic properties such as much lower magnetic loss than that of their bulk counterpart. In fact, it is just thin film metallic glasses and small-scale ribbon ones that are widely used in the power and electronics industries due to their good machinability and formability. So, we have added discussion in the introduction referring  to the reference literatures. See page 2, lines 51-57: “The mechanical properties of metallic glass - intrinsic brittleness, makes it difficult to be processed and formed, which seriously limits its practical application in engineering. As recent studies pointed out, the size effects of large ductility and yield strength can be activated for nanoscale thin film metallic glasses and even for micronscale ribbon ones, which exhibit excellent magnetic properties such as much lower magnetic loss than that of their bulk counterpart [10,11]. In fact, it is just thin film metallic glasses and small-scale ribbon ones that are widely used in the power and electronics industries duo to their good machinability and formability.”.

10. Ghidelli, M.; Idrissi, H.; Sébastien, G.; Blandin, J. J.; Raskin, J. P.; Schryvers, D.; Pardoen, T. Homogeneous flow and size dependent mechanical behavior in highly ductile Zr₆₅Ni₃₅, metallic glass films. Acta Mater. 2017, 131, 246-259, doi: 10.1016/j.actamat.2017.03.072.

11. Tian, L.; Cheng, Y. Q.; Shan, Z. W.; Li, J.; Wang, C. C.; Han, X. D.; Sun, J.; Ma, E. Approaching the ideal elastic limit of metallic glasses. Nat. Commun. 2012, 3, 609, doi: 10.1038/ncomms1619.

Point 3: I would like that the authors comment in a better way Figure 1. Specifically, it is strange that although the composition of the BMG change there is no change on the position of the diffraction hump which is always located around 45°. As a matter of facts the change of local order due to composition should induce also a change of the position of the diffraction hump see the following paper doi.org/10.1016/j.jallcom.2013.12.054 that worth to be.

Response 3: From a theoretical point of view, the change of local order due to composition should induce also a change of the position of diffraction hump. However, such changes are not observable in the resolution range detectable by conventional XRD when the composition changes are small. In this work, the Fe content is dominant and the change in Nb content is minor. Therefore, only the main wave vector peak of iron at 45° can be observed in their XRD patterns, as showed in many other XRD patterns of Fe-based metallic glasses.

Other changes:

We have carefully checked the manuscript and made some modifications in the revised manuscript.  These changes will not influence the content and framework of the paper. And we have detailedly listed and marked them in red color in revised paper.

Modified words:

Lines 36,38,40 at page 1.

Lines 42, 44, 46-50, 82, 85 at page 2.

Lines 87, 98, 107-112, 115, 119 at page 3.

Lines 130, 134-136 at page 4.

Lines 137, 138-141, 149-150, 152-153, 155, 160-166, 168-169 at page 5.

Lines 170-176, 177-179, 185, 187-188, 190-191 at page 6.

Lines 201-203, 204-207, 209-210, 212, 216 at page 7.

Lines 226, 228, 233 at page 8.

Lines 245, 250, 252 at page 9.

Revised reference number:

Lines 62, 64, 72 at page 2.

Lines 112, 117, 119, at page 3.

Line 145 at page 4.

Lines 155, 157, 165, 185 at page 5.

Lines 189, 193 at page 6.

Lines 215, 232, 236 at page 7.

Line 243 at page 8.

We appreciate for Editors/Reviewers’ warm work and hope that the correction will meet with approval.

Author Response File: Author Response.pdf

Reviewer 3 Report

Li, Dong et al. report on a comprehensive study of FeSiBPNbCu-based systems displaying enhanced soft-magnetic properties. Publication of this paper is recommended, provided some minor revision points are addressed:

(1) Please explain the SMP abbreviation also in abstract (it should be self-standing).

(2) Please quote sources of the used raw materials in the Experimental section.

Author Response

Response to Reviewer 3 Comments

Point 1: Please explain the SMP abbreviation also in abstract (it should be self-standing).

Response 1: According to the reviewer’s suggestion, we have made some modification to the abstract, which stresses more the conclusions and avoids providing more technical details. See page 1, lines16-27.

Abstract: (Fe_0.76Si_0.09B_0.1P_0.05)_99.3−xNb_xCu_0.7 (x = 0–1.5 at. %) bulk nanocrystalline alloys were prepared to investigate the alloying effects of Nb on glass forming ability, thermal stability, soft magnetic properties and crystallization behavior. It was found that the amorphous forming ability was greatly improved with the addition of minor Nb. The thermal stability of Nb-containing alloy is significantly improved because the initial crystallization temperature and crystallization activation of the primary phase were obviously improved compared with that of the Nb-free alloy. Further, the larger intervals of two-phase crystallization temperature and the significantly higher activation energy of crystallization of the second phase in the Nb-containing alloys favor the formation of a single α-Fe(Si) nanocrystalline structure. And Nb-containing alloys exhibit excellent soft magnetic properties, including high saturation magnetization of 1.42-1.49 T, low coercivity (H_c) of around 1.0 A/m and high permeability of about 18,000 at 1 kHz, which makes the alloys promising soft magnetic materials for industrial applications.

Point 2: Please quote sources of the used raw materials in the Experimental section.

Response 2: According to the suggestion, we explain the source of raw material in the experiment part. See page 2, lines 82-85 (Fe_0.76Si_0.09B_0.1P_0.05)_99.3−xNb_xCu_0.7 (x = 0-1.5) alloy ingots were melted by induction melting of pure Fe (99.99 wt.%), Nb (99.9 wt.%) and Cu (99.99 wt.%), crystalline Si (99.99 wt.%) and B (99.9 wt.%) metalloids, and Fe₃P (99.9 wt.%) pre-alloy of Beijing Zhongjin new material technology co., Ltd (CNM) in a high-purity argon atmosphere.

Other changes:

We have carefully checked the manuscript and made some modifications in the revised manuscript.  These changes will not influence the content and framework of the paper. And we have detailedly listed and marked them in red color in revised paper.

Modified words:

Lines 36,38,40 at page 1.

Lines 42, 44, 46-50, 82, 85 at page 2.

Lines 87, 98, 107-112, 115, 119 at page 3.

Lines 130, 134-136 at page 4.

Lines 137, 138-141, 149-150, 152-153, 155, 160-166, 168-169 at page 5.

Lines 170-176, 177-179, 185, 187-188, 190-191 at page 6.

Lines 201-203, 204-207, 209-210, 212, 216 at page 7.

Lines 226, 228, 233 at page 8.

Lines 245, 250, 252 at page 9.

Revised reference number:

Lines 62, 64, 72 at page 2.

Lines 112, 117, 119, at page 3.

Line 145 at page 4.

Lines 155, 157, 165, 185 at page 5.

Lines 189, 193 at page 6.

Lines 215, 232, 236 at page 7.

Line 243 at page 8.

We appreciate for Editors/Reviewers’ warm work and hope that the correction will meet with approval.

Round  2

Reviewer 2 Report

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