Uncovering the Effect of CeO2 on the Microstructure and Properties of TiAl/WC Coatings on Titanium Alloy
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article studies the effect of CeO2 additive on the properties of TiAl/WC coatings on a TC21 titanium alloy substrate produced by laser cladding. The work is of interest to researchers involved in improving the wear resistance of structural materials.
The article has the following comments.
1. Lines 120-121 say "After compaction ...". What is meant by the word compaction?
2. It is unclear why the authors classify the coating as a metal matrix composite (MMC) if it contains a minor amount of β-Ti (see the line 159). Rather, it is a cermet coating, but not MMC.
3. Lines 192-193 say that the atomic ratio of Ti and C for points 3 and 5 is about 1:1, but in Table 2 we see Ti/C = 26.08/51.52 for point 3 and 37.54/51.95 for point 5.
4. Lines 336-338 say "The increase in hardness is mainly because the added WC powder can be decomposed into free C atoms and W atoms under the high energy of laser cladding". But, the decomposition of carbide WC, rather, should lead to a decrease, but not increase in hardness.
5. In conclusion (lines 415-417) it is stated that “The microhardness and wear resistance of the TiAl/WC/CeO2 MMC coatings were dramatically enhanced due to the reinforcing phases of homogeneous distribution...”. However, Fig. 8 and Fig. 9 show that with the addition of CeO2, only the wear resistance changes dramatically, but the microhardness varies within only 8%.
Author Response
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Reviewer 2 Report
Comments and Suggestions for AuthorsThe work concerns the influence of CeO2 on MMC coatings on the phase distribution, microstructure evolution, formation mechanisms, and microhardness. It has been shown that this addition affects the morphology, size and distribution of the TiC strengthening phase in MMC coatings. CeO2 also affects fine-grained reinforcement and dispersion reinforcement, which results in higher hardness and wear resistance.
The work is well written and constitutes a coherent whole. It is suitable for printing in Coatings, both technically (interesting diagrams, well-prepared figures) and substantively. I only have minor comments about the experiment:
- are the authors sure that such a small amount of CeO2 can be visible by XRD (is the resolving power of the diffractometer sufficient?)
- what database was used for XRD phase analysis?
- what does the peak at the 2 theta angle ~62 for No.1 come from?
Vertical lines could be drawn in the XRD figure to facilitate comparison of the positions of diffraction peaks.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsPlease see the attachment.
Comments for author File: Comments.pdf
ok
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