Effects of Heat Treatment on Microstructures and Properties of Cold Rolled Ti-0.3Ni Sheets as Bipolar Plates for PEMFC

Round 1

Reviewer 1 Report

   The present manuscript reports that effects of heat treatment process on mechanical, electrochemical, and corrosion resistance properties of cold rolled Ti-0.3Ni sheets. The mechanical and corrosion properties of Ti-0.3Ni plates were discussed by considering the effect of precipitation of Ti₂Ni intermetallic compounds on microstructure.

   Although the experimental results on mechanical and electrochemical properties of the cold rolled Ti-0.3Ni sheet are well described, the discussion for the related experimental results is insufficient. For example, the effect of forming a protective film and corrosion resistance according to the volume fraction of the Ti₂Ni intermetallic compound needs to be discussed.

   In addition, Sedriks et al. reported that introduction of Ti₂Ni intermetallic compounds enhance the corrosion resistance of titanium by increasing the efficiency of cathodic process. However, the authors determined that the precipitation of Ti₂Ni deteriorates mechanical properties of titanium alloy, thus reducing the corrosion resistance. Therefore, it is necessary to discuss the differences in both results, together with major revisions suggested below:

• It is necessary to use the full name of the abbreviation for the readers, e.g. OCPs in line 16.
• In the section of 3.4., it is necessary to add the contents of the corrosion potential(E_corr) results.
• In the case of corrosion current densities(i_corr) mentioned in line 206, it is necessary to include the details for the evaluation method.
• In line 231~235, determining the passive film formation due to the valve metal properties, the retlated references need to added for the sake of readers.
• In the potentiodynamic polarization curve shown in Fig. 4, it is recommended to enlarge the active state region as shown in Fig. 8.
• Finally, minor typos need to be corrected (e.g. Fig. 5 in line 278, and Fig. 6 in line 282)

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This is a typical study on Metallography, in this case of a Ti-Ni alloy for bipolar electrodes appliactions in fuel cell. In that sense, the metallographic characterization is acccompanied by an evaluation of it electrochemical performance.

The novelty of that contribution is related to the increasing relevance of green hydrogen production using water splitting.
Nowadays the production of green hydrogen involves the use of electrolyzers and one of the problems to be solved is the availability of appropriate electrodes. 
This manuscript discusses such a problem and gives a possible solution through the T-Ni alloy, which is the subject discussed in that study.

The manuscript could be accepted for publication in this journal after minor improvement for the English language.

 

Author Response

Thanks a lot for your comment. The language in this article has been checked carefully and corrected in the revised manuscript marked as green.

Reviewer 3 Report

The article is interesting and in my opinion it is suitable for printing.

Author Response

Thank you for reviewing!