The Effect of CeO₂ Content on the Microstructure and Properties of TiC/WC/Co Composite Cladding Layers

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Despite extensive research on single-phase reinforced coatings, the synergistic effects of CeO₂ addition in dual-hard-phase (TiC/WC) composite systems remain largely unexplored. This study addresses this knowledge gap by systematically investigating the influence of CeO₂ concentration (0-7.0 wt.%) on the microstructural evolution and mechanical properties of laser-clad TiC/WC/Co composite coatings on nodular cast iron substrates. In this study, by adding different contents of the rare earth oxide CeO₂, the effects of CeO₂ on the microstructure and mechanical properties of the laser-cladded TiC/WC/Co composite coating were systematically investigated.

The manuscript is clear, well-structured and useful for researchers in the field of chemistry and materials science. The presented literature review is clear, comprehensive and relevant to the field of study. All cited references are recent publications, not older than 5 years. The research conducted by the authors is relevant and complete. In the concentration range of CeO₂ (0-7.0 wt.%), both advantages and disadvantages of doping are revealed. The presented conclusions fully reflect the entire spectrum of the conducted research. It is difficult to find fault with the scientific component of the manuscript. I would like to recommend the authors to use brighter and more contrasting colors when designing figures. Arrows and explanatory captions are poorly visible in the images from the scanning electron microscope.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Limitations need to be overcome in a revision, e.g. :

1. The Abstract needs to be shorter and more focussed on aims and findings.
2. Temperature range of workpiece during laser treatment?
3. Open-circuit electrode potentials of cast iron, graphite, cobalt and the coating (with reference to bimetallic corrosion.
4. Several values are stated to an excessive degree of precision, e.g. ‘When the CeO₂ content is 4 wt.%, the hardness of the coating reaches its peak value (91.37 HRC), which is approximately 2.57 times the hardness of the substrate.’ Use margins of accuracy to guide stated precision.
5. State margins of accuracy.
6. Through-porosity of the coating (with respect to corrosion)?
7. Tendency to cracking of cast iron is mentioned early in the script but not followed up in results on initiation or propagation of cracking.
8. Discuss aspects of larger-scale processing and materials/process sustainability/environmental suitability.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this study, a TiC/WC/Co composite coating layer (with CeO₂ added) was created on a ductile cast iron substrate. The effects of CeO₂ content on the microstructure, phase composition, and hardness of the coating layer were systematically studied, and an optimal CeO₂ content was found to exist. The content of the research is interesting, but I have some concerns, which I would appreciate your consideration.

• The magnification of Figure 6 is not high, so the TiC particles are not visible. I recommend changing to an image with a higher magnification. Also, please show a histogram of the measured TiC particle size. Also, please add an explanation of the method for measuring the particle size.
• In Figure 10(a), only the S3 sample has a high hardness value at a distance of 1.5 mm from the surface. This is thought to be the main reason for the increase in the average hardness of the cladding layer of the S3 sample. Please consider the variability of the measurement data. Also, in Fig. 10(a), the hardness of S4 is higher than that of S2 in the cladding layer. However, in Fig. 10(b), the average hardness of S2 (85.81) is higher than that of S4 (84.61). Isn't this a contradiction?
• Considering the variability of the data, it is possible to consider that the average hardness shown in Figure 10(b) is almost the same value among the S2, S3, and S4 samples. Please add any discussion on this point.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Ductile iron has a wide range of uses. Its mechanical properties, as with other materials, are influenced by the microstructure and, in the case of cast iron, by the shape of the excluded graphite. The article examines the impact of CeO₂ on the microstructure and properties of TiC/WC/Co cladding layers. In the introduction, the authors introduce the issues of the given area and draw on the available literature.
The methodology and materials are also well described.
The results achieved by the authors are described in detail, and the discussion on them is sufficient and understandable, without comments.
The conclusion describes the important results achieved and is clearly formulated.
I have the following comments on the article:

- The term "ductile iron (DI)" should be used correctly throughout the text

- What was the S and P content in the ductile iron (Table 1)

- What was the carbon equivalent CE (table 1)

- What was the matrix of the microstructure (ferritic, pearlitic, ...)?

- What was the nodularity and the starting mechanical properties of the material?

- Why was Rockwell hardness chosen and not Brinell HB

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf