High-Temperature Properties and Applications of Si-Based Polymer-Derived Ceramics: A Review
Round 1
Reviewer 1 Report
This topical review by Ren and co-authors gives a current overview of the field of preceramic polymers for high-temperature applications.
In general, the manuscript is well-written and well-structured. In particular, the graphic highlights of each chapter are done quite nicely. The topic itself is interesting and generally warrants a review of the current literature.
One point of criticism involves the introduction section: I believe that the introduction section requires a new structure. In particular, I would have wished to see a general overview on pathways towards improving the thermal stability of ceramics obtained from Si-based ceramics, with regard to the relevant factors mentioned (microstructural changes, crystallization tendencies, effect of heteroatoms,…). Towards the end of this section, the current listing of individual papers (starting from L83, “Xie et al.”,…) does not help the reader to obtain a good overview of the current state of the art.
With regard to section 2.2 (MEMS), I do not really see the “high-temperature” aspects? Why is this chapter included in this review? It appears as if the contents relevant to HT applications are missing.
In this regard, I think it is necessary to clearly define what is meant by “high temperature” in the context of this work, and to stick to this temperature range in all applications mentioned. For example, I would not consider 350 °C or 700 °C as “high temperature” (as suggested in Table 1). Of course, this is a matter of definition, but I nonetheless recommend to strengthen the focus, otherwise the work may be too broad, lacking the required detail.
Some minor comments:
L73 and following: The authors refer to “microstructures”; however, it is not clear what is meant here. This should be described more clearly.
Fig.3: I assume that the line from SiTiOC to Al2O3 should be removed.
Fig.9 (and maybe other Figs. as well): Are these pictures taken from publications? If yes, the references are missing in the figure captions.
Author Response
General Comment Reviewer #1: This manuscript investigated structure-related properties of polymer-derived ceramics at various environment conditions. Reviewer thinks that the reviewed topics and contents in this manuscript can be certainly contributed to this research field and worth publishing in this journal "Materials".
Reviewer #1 Author General Response: We appreciate your valuable recommendation.
General Comment Reviewer #2: This topical review by Ren and co-authors gives a current overview of the field of preceramic polymers for high-temperature applications.
In general, the manuscript is well-written and well-structured. In particular, the graphic highlights of each chapter are done quite nicely. The topic itself is interesting and generally warrants a review of the current literature.
Reviewer #2 Author General Response: Thank you for your comments.
Reviewer #2 Comment #1: One point of criticism involves the introduction section: I believe that the introduction section requires a new structure. In particular, I would have wished to see a general overview on pathways towards improving the thermal stability of ceramics obtained from Si-based ceramics, with regard to the relevant factors mentioned (microstructural changes, crystallization tendencies, effect of heteroatoms,…). Towards the end of this section, the current listing of individual papers (starting from L83, “Xie et al.”,…) does not help the reader to obtain a good overview of the current state of the art.
Reviewer #2 Author Response #1: Thank you for your comments. The section starting from L83, “Xie et al. …” has been rewritten and refined. The listings of individual papers are removed and simpler illustration of enhance mechanisms are remained.
Changes made:
Incorporating other elements, such as B, Al, Nb, Zr, Ti, or Hf to the Si-C-N or Si-O-C systems may greatly enhance the thermostability of ceramic products via preventing or impeding the crystallization and phase segregation of the ceramic phases in inert or oxidizing environments. Initially, at the crosslinking stage, B atoms may improve the formation of crosslinking network and increased the yield and structural density of SiBOC. Upon polymer-to-ceramic conversion, doped elements may form additional phases (e.g., TiO2, HfO2, ZrO2) and lead to nanocomposite-like structures of metal-oxide/amorphous ceramic; or dissolve into and alter the amorphous phase (e.g., SiBOC, SiAlOC) which eventually segregate into additional phases (BN, Al2O3) at higher temperatures. At the amorphous stage, the superior stability of the B- or Al- doped amorphous phase significantly enhance the oxidation resistance of SiBOC ceramics. For example, SiAlOC may stay amorphous at much higher temperature (up to 1400 – 1500 °C) compared to SiOC phase (crystallize at ~ 1300 °C). Doped SiOC phase also controlled the diffusion of O2 at high temperatures and inhibited the decomposition of microstructures.
After forming additional microstructures, the presence of TiO2, HfO2 or ZrO2 in the amorphous PDC matrix prevent the crystallization and decomposition of the amorphous phase. TiO2 nanocrystals also improved the viscosity of the microstructures at high temperatures which deterred collapse in the TiO2/SiO2 structure.
Reviewer #2 Comment #2: With regard to section 2.2 (MEMS), I do not really see the “high-temperature” aspects? Why is this chapter included in this review? It appears as if the contents relevant to HT applications are missing.
Reviewer #2 Author Response #2: Thank you for your comments. The MEMS section was included for the following reasons. First of all, MEMS was one of the earliest developed application of PDCs due to the outstanding “processability.” The MEMS is meaningful due to the existing of high-temperature sensors (for example, for turbine engines) to monitor high-temperature environments, however, a sensor with only high-temperature sensor head material is not functioning, if any other part of the sensor part (e.g., circuit, enclosure, structural support) cannot endure the harsh environment. We consider, PDC MEMS can function well for this type of situation. Therefore, we would like to keep this section.
Reviewer #2 Comment #3: In this regard, I think it is necessary to clearly define what is meant by “high temperature” in the context of this work, and to stick to this temperature range in all applications mentioned. For example, I would not consider 350 °C or 700 °C as “high temperature” (as suggested in Table 1). Of course, this is a matter of definition, but I nonetheless recommend to strengthen the focus, otherwise the work may be too broad, lacking the required detail.
Reviewer #2 Author Response #3: Thank you for your comments. We agree that 350 °C are not “high-temperature” enough. We have removed the applications < 700 °C from the table. Initially, the “high-temperature” were determined based on the specific applications or functionality, e.g., before PDCs, some applications may only had maximum working temperature ~ 200 °C, however with PDCs, if the application temperature could be significantly raised to ~500 °C, we considered it “high-temperature” for these specific applications.
Changes made:
- “High-temperature” for this review is now defined as “close to or higher than 1000 °C” in the abstract.
- Contents with application temperature less than 700 °C have been removed from the table.
Reviewer #2 Comment #4: L73 and following: The authors refer to “microstructures”; however, it is not clear what is meant here. This should be described more clearly.
Reviewer #2 Author Response #4: Thank you for your comments. The section where the “microstructures” was referred has been rewritten due to the previous comment (Reviewer #2 Comment #2).
Reviewer #2 Comment #5: Fig.3: I assume that the line from SiTiOC to Al2O3 should be removed.
Reviewer #2 Author Response #5: Thank you for your comments. The figure 3 has been corrected.
Reviewer #2 Comment #6: Fig.9 (and maybe other Figs. as well): Are these pictures taken from publications? If yes, the references are missing in the figure captions.
Reviewer #2 Author Response #6: Thank you for your comments. All figures were cited in the text. We have also included the citation in the figure captions.
General Comment Reviewer #3: Review on PDCs is very useful and it is right time.
Reviewer #3 Author General Response: Thank you for your comments.
Reviewer #3 Comment #1: write full form of all key words - expand MEMS.
Reviewer #3 Author Response #1: Thank you for your comments. MEMS are expended in the key words.
Reviewer #3 Comment #2: This review mainly focuses only on application aspects; in addition add a few subsections of processing, microstructure, mechanical properties in detail.
Reviewer #3 Author Response #2: Thank you for your comments. We also agree that the processing, microstructure, and mechanical properties are greatly important for developing and commercializing PDC materials. However, there already exist numbers of other review articles on these topics. We would like to include them as references and redirect our readers towards those works.
For our work, as the title suggests, this review was prepared as a compact review that focus mainly on the high-temperature applications. The overall processing of PDCs is presented in detail in the introduction section. Processing is also mentioned in the application section since the processing techniques are very different by the applications. Microstructures are also illustrated in the introduction section; however, we consider this section was not the major focus of this review, therefore, we did not delve deeper into it.
For the properties, mechanical properties are discussed in only some applications (e.g., fibers, composites) because some other applications are not requiring the determination of mechanical performance. The outstanding mechanical performances are included in the table (if they were determined in the research).
Changes made: Following sentence/references have been included in the revised manuscript: “Further information on the processing/manufacturing[6,26-32], physical and mechanical properties[26-31,33-37] and micro/nanostructures[5,26,27,29,31,32,34,35,38-40] of PDCs can be found in the previously published review articles.”
Reviewer #3 Comment #3: For all figures and tables need to obtain the copyright permissions, wherever applicable.
Reviewer #3 Author Response #3: Thank you for your comments. The all copyright files were submitted in a separate file to the publisher. In the captions, all the copyrights are properly cited.
Reviewer #3 Comment #4: check the spellings and grammar for the whole manuscript; for e.g. page no: 11; line no: 335: correct the spelling of word "requiredetection". page no: 13; ; line no: 380; check Fe3Si; 3 should be in the subscript.
Reviewer #3 Author Response #4: Thank you for your comments. The spelling errors have been corrected.
Reviewer #3 Comment #5: Add a few more tables on summarizing the processing, mechanical and physical properties similar to Table 1.
Reviewer #3 Author Response #5: Thank you for your comments. As mentioned in (Reviewer #3 Comment #2) that we did include outstanding mechanical performances of high-temperature ceramic products under certain applications (fibers, matrices, coatings, etc). Besides, there are no sufficient amount of data to justify an additional table purely on mechanical and other physical properties.
Reviewer #3 Comment #6: Given references may not be sufficient enough for such kind of review; broaden the sections and accordingly add more references to make it more reader friendly of this review.
Reviewer #3 Author Response #6: Thank you for your comments. We have increased the citation numbers on the existing contents to further support it.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Review on PDCs is very useful and it is right time. Following are my suggestions to improve the quality of this manuscript:
1) write full form of all key words - expand MEMS
2) This review mainly focuses only on application aspects; in addition add a few subsections of processing, microstructure, mechanical properties in detail.
3) For all figures and tables need to obtain the copyright permissions, wherever applicable.
4) check the spellings and grammar for the whole manuscript; for e.g. page no: 11; line no: 335: correct the spelling of word "requiredetection". page no: 13; ; line no: 380; check Fe3Si; 3 should be in the subscript.
5) Add a few more tables on summarizing the processing, mechanical and physical properties similar to Table 1.
6) Given references may not be sufficient enough for such kind of review; broaden the sections and accordingly add more references to make it more reader friendly of this review.
Author Response
General Comment Reviewer #3: Review on PDCs is very useful and it is right time.
Reviewer #3 Author General Response: Thank you for your comments.
Reviewer #3 Comment #1: write full form of all key words - expand MEMS.
Reviewer #3 Author Response #1: Thank you for your comments. MEMS are expended in the key words.
Reviewer #3 Comment #2: This review mainly focuses only on application aspects; in addition add a few subsections of processing, microstructure, mechanical properties in detail.
Reviewer #3 Author Response #2: Thank you for your comments. We also agree that the processing, microstructure, and mechanical properties are greatly important for developing and commercializing PDC materials. However, there already exist numbers of other review articles on these topics. We would like to include them as references and redirect our readers towards those works.
For our work, as the title suggests, this review was prepared as a compact review that focus mainly on the high-temperature applications. The overall processing of PDCs is presented in detail in the introduction section. Processing is also mentioned in the application section since the processing techniques are very different by the applications. Microstructures are also illustrated in the introduction section; however, we consider this section was not the major focus of this review, therefore, we did not delve deeper into it.
For the properties, mechanical properties are discussed in only some applications (e.g., fibers, composites) because some other applications are not requiring the determination of mechanical performance. The outstanding mechanical performances are included in the table (if they were determined in the research).
Changes made: Following sentence/references have been included in the revised manuscript: “Further information on the processing/manufacturing[6,26-32], physical and mechanical properties[26-31,33-37] and micro/nanostructures[5,26,27,29,31,32,34,35,38-40] of PDCs can be found in the previously published review articles.”
Reviewer #3 Comment #3: For all figures and tables need to obtain the copyright permissions, wherever applicable.
Reviewer #3 Author Response #3: Thank you for your comments. The all copyright files were submitted in a separate file to the publisher. In the captions, all the copyrights are properly cited.
Reviewer #3 Comment #4: check the spellings and grammar for the whole manuscript; for e.g. page no: 11; line no: 335: correct the spelling of word "requiredetection". page no: 13; ; line no: 380; check Fe3Si; 3 should be in the subscript.
Reviewer #3 Author Response #4: Thank you for your comments. The spelling errors have been corrected.
Reviewer #3 Comment #5: Add a few more tables on summarizing the processing, mechanical and physical properties similar to Table 1.
Reviewer #3 Author Response #5: Thank you for your comments. As mentioned in (Reviewer #3 Comment #2) that we did include outstanding mechanical performances of high-temperature ceramic products under certain applications (fibers, matrices, coatings, etc). Besides, there are no sufficient amount of data to justify an additional table purely on mechanical and other physical properties.
Reviewer #3 Comment #6: Given references may not be sufficient enough for such kind of review; broaden the sections and accordingly add more references to make it more reader friendly of this review.
Reviewer #3 Author Response #6: Thank you for your comments. We have increased the citation numbers on the existing contents to further support it.
Changes made: The following new citations are included: # 26-40, # 73, # 76, # 77, # 79, # 83, # 84, # 85, # 89, # 90. Correspondingly, new contents has been added to Table 1.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have adequately responded to all comments.
