Study on High-Temperature Oxidation Behavior of Platinum-Clad Nickel Composite Wire

Round 1

Reviewer 1 Report

See the attached note. 

Comments for author File: Comments.pdf

Author Response

Thank you for your valuable comments on my article, my corrections and responses are as follows:

(1) The reference number has been changed.

(2) This value has been measured and calibrated and is correct. 5 µm and 8 µm are the average values and are the design values for our products. The amplitude of the thicknesses is normal and is caused by the processing, but we also note that they have a minimum thickness of 3.5 µm and 5.5 µm respectively and that the nickel core wire is still covered with a platinum layer and is therefore still usable.

(3) Figure 4(h, v) is correct. figure 4(v) is at 700° X 3h and the grains are visible on the surface, whereas figure 4(x) is at 800° X 3h and the surface is fully oxidised and no grains are visible.

(4) Figures 2, 3, 4, 5, 6, 7, 10, 12, 13, 14, 15 have been modified.

(5) Element labels for surface and line scans have been added

(6) References [1], [5], [8], [12], [15] have been modified.

(7) Reference [9] has been replaced

(8) References [4], [17], [24] [25] are in Chinese with the following DOI numbers:

[4] DOI: 10.13873/J.1000-9787(2022)07-0081-04

[17] DOI: 10.16786/j.cnki.1671-8887.eem.2006.01.002

[24] DOI: 10.13873/j.1000-97872000.06.003

[25] DOI: 10.27200/d.cnki.gkmlu.2021.001357

(9) Document [18] is in Chinese. This document is very important to my article, it was cited in 2 places, but there is no IDO number, I don't know how to deal with it.

(10) Other changes were made using track changes, visible in the manuscript.

Reviewer 2 Report

The manuscript deals with the short-term oxidation behaviour of a platinum-clad nickel composite wire. Pt coating should  provide oxidation protection to nickel core as a way for using this material as lead wires. In general , characterization of the annealed materials is well done, although after reading the overall manuscript some questions arises.

 

1) The authors state that the diffusion pathway for nickel at low temperatures (500 °C) was mainly bulk diffusion , while  an increasing contribution of intergranular diffusion takes place with increasing temperature. This has no sense. The opposite is true, i.e. intergranular diffusion becomes more important as the temperature decreases. 

 

2) When the composite is exposed there is an increase of the thickness due to inward difussion of Pt towards the nickel composite and outward nickel diffusion from the core towrads the Pt coating. According to the equilibrium phase diagram Pt is totally miscible in nickel above 600-650°C, but below this temperature different intermetallic phases depending on the nickel content. Thus, different intermetallic phases should be present in the Pt-Ni coatings. Also in the samples exposed at 700 and 800°C. In fact, the microstructructe evidences the presence of two-phase regions in the figure 10 corresponding to the sample exposed 2h at 800°C. These intermetallic phases are usually brittle hard-phases and they accout for the different mechanical behaviour of the alloys when the Ni content is changed. This should be properly considered in the results and  discussion sections.

 

3) In Figures 9 and 10, labelling of compositional line scans for Pt, Ni and O is wrong.

In opinion of this reviewer the Engish is good

Author Response

Thank you for your valuable comments on my article, my corrections and responses are as follows:

(1) Section 4.2 "Therefore, at low temperatures (500 °C), the diffusion pathway for nickel was mainly bulk diffusion." has been deleted, and the conclusions were also modified.

(2) The results of the line scan showed that the composition of pt and Ni was continuously changing at 800°, so I concluded that Pt and Ni formed a complete miscible solution. Meanwhile, in another study of mine, the diffusion behaviour under vacuum conditions at 450-850° was investigated and electron probe analysis of the interface was carried out, neither of which revealed the presence of an intermediate phase.

（3）Figures 2, 3, 4, 5, 6, 7, 10, 12, 13, 14, 15 have been modified.

(4) Other changes were made using track changes, visible in the manuscript.

Reviewer 3 Report

The manuscript is devoted to the oxidation behavior of platinum-clad nickel composite wires at high temperatures. 

The oxidized samples were examined by the authors only using SEM and EDX. In my opinion the scientific level of the manuscript is not high. However, on the other hand the topic is valuable for technical practice of the temperature sensors, so the paper may be of interest to scientific community. Therefore I believe the work is worth publishing, but the manuscript needs major revision.

My specific comments and suggestions in the order in which they appear in the text of the manuscript:

1. The main objections concern figures, that are with errors or are illegible. Especially: 
- The location of the notations (a), (b) etc. in the figures needs improvement (Fig.2, Fig.3, Fig.4, Fig.15). 
- All EDX energy spectrum analysis results are illegible, they should be enlarged (especially element symbols - Fig.5, Fig.6, Fig.15).

2. The title of the section 2 (Materials and experiments) would be better called Materials and methods, so familiar to readers of the scientific journal Metals. 

3. section 3.3, page 7 
"NiO, Ni3O4, and Ni2O3". The subscript is missing in the formulas of chemical compounds.

4. section 3.3, page 7 
"therefore, we ascertained that the black substance was NiO". 
The sample was examined with an SEM microscope at room temperature, so why according to the authors the black substance was NiO and not Ni₂O₃? What is the proof of the authors' theorem?

5. In the title of Figure 7 is missing (d) - platinum mapping analysis.

6. Figure 10 
Please check the correctness of the descriptions in the figure title. It says: (c) platinum; (d) oxygen; (e) nickel. It should be: (c) nickel, (d) platinum, (e) oxygen.

7. page 12, Figure 12. Variation curves 
It should be: Figure 13

8. page 13, line 9 from the top 
"Figure 13 shows..." 
It should be: Figure 14 shows...

9. page 13, title of the figure 
"Figure 13. Schematic diagram of the..." 
It should be: Figure 14

10. page 13, line 3 from the bottom 
"as shown in Figure 14."  
It should be: Figure 15

 

Moderate editing of English language required.

Author Response

Thank you for your valuable comments on my article, my corrections and responses are as follows:

(1) Figures 2, 3, 4, 5, 6, 7, 10, 12, 13, 14, 15 have been amended

(2) The title of Section 2 has been amended to read "Materials and Methods".

(3) Ni2O3 can only exist at low temperatures. When heated to 400-450°, it decomposes into Ni3O4, and when the temperature reaches 600°C, Ni3O4 is reduced to NiO, and these processes are irreversible. The oxidation temperature of this project is greater than 700°, therefore, I think the oxide layer is NiO.

(4) Other changes were made using track changes, visible in the manuscript.

Round 2

Reviewer 3 Report

In the revised manuscript the authors addressed my comments and recommendations, and answered my questions. I believe the manuscript has been sufficiently improved and it can be accepted in present form.

 

Minor editing of English language required.