Improved Properties of Ceramic Shells by Optimizing the Surface Composition from Lanthanide-Based Composites
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
This paper presents many experimental results in a scientifically sound manner, but it still needs some improvements before being accepted for publication:
-The experimental section should be re-written because it should contain only experimental procedures. Please details the experimental protocols.
-Table 2: Why the chemical composition of CMSX-4 alloy is not 100 wt.%?
-Please check the total values in other tables also. It should be 100%.
-Reference format has errors. Please check.
-Many typos (including subscripts and superscripts) are found in the manuscript. Please proofread again.
-Line 141: The TG curve is mentioned but DTG curve is shown in Figure 3. Suggest to include TG and DTG curve in Figure 3 and discuss together.
-Figure 3(b): What is the corresponded DTG signal at about 400 C? Why DTG signal is not shown after 1400 C but the discussion was made up to 1500 C?
-Line 177: Please rephrase this sentence.
-The font sizes in the graphs are too small. The readers might have difficulty to read when these figures are published in journal format.
-The Results and Discussion lacks proper discussion which should be supported by previous references. It will enhance the depth and validity of the findings.
-Conclusion should be written in paragraph form. It should cover key findings, their implications, limitations of the study, and suggestions for future research.
-Some inconsistencies are found in the reference format.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
The study under review presents an exploration of the utilisation of synthesised LaAlO₃ and La₂Si₂O₇ mixed powders, which were employed in varying stoichiometric ratios for the fabrication of investment casting shells. Additionally, a comprehensive examination of the rheological and mechanical properties of the resulting material was conducted. The manuscript is well-structured and exhibits a coherent flow throughout. The introduction adeptly articulates the rationale underlying the authors' research, is thoroughly referenced, and underscores the originality of the study, which could benefit from a more detailed elaboration. The experimental section delineates the research scope and the methodologies employed with clarity. Furthermore, the results and discussion sections present a comprehensive analysis of the findings. However, the manuscript would benefit from a more in-depth engagement with relevant literature to strengthen its arguments. A minor critique pertains to specific sections that may be perceived as overly descriptive. The logical progression across the various sections is commendable, and the conclusion effectively encapsulates the findings while highlighting the primary observations. In light of these considerations, I recommend the manuscript for publication, contingent upon minor revisions.
Correct the formatting in Tables 1 and 2 (expand the corresponding columns).
In Figure 4, correct the unit of dynamic viscosity (mPa·s).
Correct the formatting of the paragraphs in lines 313 and 323.
Include the practical significance of the study in the conclusion.
There are grammatical errors in the article. Correct typos and word order.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors
This paper presents an innovative approach to improving the high-temperature stability and chemical inertness of ceramic shell face coats for nickel-based single-crystal superalloys. By introducing lanthanide oxide-based materials, the authors effectively address the limitations of conventional alumina-based ceramic shells and propose a promising solution to enhance investment casting performance. Before it will be suitable for publication it needs some corrections:
1- The study introduces a fresh perspective by employing La-based composites in ceramic shells. The findings provide valuable insights into phase transformations, microstructural stability, and slurry characteristics, making this work relevant to both academia and industry.
2- The experimental design is well-structured, with systematic sintering studies and mechanical evaluations. However, a more detailed discussion on the selection criteria for specific molar ratios and sintering temperatures would strengthen the argument.
2- The manuscript is generally well-organized. Some sections, particularly those on phase formation mechanisms, could benefit from additional clarification and deeper discussions supported by thermodynamic analysis.
3- The authors convincingly demonstrate the superior performance of LAS and LA11S shells, but additional comparative analysis with industry-standard ceramic shell materials would enhance the discussion.
4- Provide a more thorough analysis of the phase transformation mechanisms, possibly incorporating thermodynamic simulations.
5- Expand on the rationale behind molar ratio selections for the different compositions.
6- Clarify the practical implications of using LA, LAS, and LA11S shells in real-world casting environments with additional case studies.
7- Improve the discussion around slag formation in castings and its impact on alloy integrity over multiple recycling cycles.
8- How do you anticipate the cost-effectiveness of these new shell materials compared to existing industrial solutions?
9- What potential challenges might arise in scaling up the production of these ceramic shells for commercial casting operations?
10- Could further optimization of the particle size distribution of LA, LAS, and LA11S powders lead to additional improvements in slurry performance?
11- How does the oxygen diffusion inhibition of LaAl11O18 compare to conventional ceramic coatings used in aerospace applications?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for Authors
The authors addressed almost all of the required suggestions; only a bit of organization is needed in the conclusion section (line spacing and removal of numbering)
