Transformation Pathways of Ferromagnetic Mn-Al-Ga-Ni

Round 1

Reviewer 1 Report

The authors investigated magnetic properties of Mn-Al-Ga-Ni alloy with Ni of 3 at.-% and . A new transformation mechanism during heat-treatment of Mn-Al-Ga-Ni alloy which involves a phase reaction from κ to τ was explored and discussed. The research contains valuable data and provide a possible way to increasing the coercivity. It can be published after addressing the following comments.

1. The authors should explain the choice of the proportions of the Ni. The possible influence of other proportions can also be predicted (optional).

2. The research mentioned that the BHmax of Mn-Al-Ga-Ni alloy is very small. Thus, the possible applications of the alloy (especially based on its magnetism) should be discussed.

3. Some spelling and grammar mistakes (e.g. directl in line 399) exist in the manuscript. Please carefully check the whole manuscript.

Author Response

Please see attached comments for authors reply to reviewers.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper "Transformation Pathways of Ferromagnetic Mn-Al-Ga-Ni" by Shane Palmer et. al. is devoted to magnetic and microstructural studies of the permanent magnets composed of Mn-Al-Ga and Ni. The manuscript is instructive and loaded with information. This paper fits well with the aims and scopes of the MDPI Magnetochemistry Journal. I recommend accepting this paper after minor revision.

1. I recommend splitting long paragraphs into smaller segments. The text in its present form is not that easy to understand.

2. There were 4 alloys studied in the paper. However, results and discussion is provided for alloys 3 and 4 only. No conclusions were derived from alloys 1 and 2. For example, alloys 2 and 3 differed in Mn purity. Seems that it was ok to use Mn of moderate purity, right? What exactly happened to alloy 1?

3. It is clear that the ternary composition was chosen to expand the work by Mix et al., ref. [13]. But, within the discussion section, it is not clear what exactly expands over the results published by Mix.

My overall impression is that this text looks like a summary of a Ph.D. Thesis. It is well-written and provides an elaborate discussion. However, it contains too much info and it may have been better structured. What I mean is that it causes questions and probably provides answers, but it is difficult to find them in the massive description. For example, You replicated the study by Mix et al. Did your results replicate those by Mix? Did you achieve the same saturation magnetization? Or was it better, or worse? Why did you use 4 alloys, but not just 2? What differences caused different heat treatments of alloy 4 (table 5)? You showed dendritic microstructure and phase segregation, both on the micron scale. At the same time, the discussion section describes microscopic magnetic phenomena. But what differences in crystallite size can be derived from XRD measurements?

However, this is some general impression from a good paper that does not affect my decision: minor revision.

Author Response

Please see attached file for authors reply to reviewers comments.

Author Response File: Author Response.docx