Ti/Cu/Kovar Multilayer Interlayer PTLP Diffusion Bonding Si3N4/Ht250
Round 1
Reviewer 1 Report
In the present manuscript, authors aim to study the effect of temperature and holding time of partial transient liquid phase (PTLP) diffusion bonding between Si3N4 ceramics and cast iron using Ti/Cu/Kovar/Cu/Ti interlayer on the microstructure and mechanical properties of the joint. Although, the work presented in the manuscript is interesting, there are several major concerns about the way manuscript is written and the way data is presented.
1- The manuscript is written in a very poor English.
a) There are many grammatical mistakes in the text like: “the joint transition was more natural, and the interface was completely”.
b) Terms like “good casting performance …” are very general and are not scientific. More specific details about a specific casting property should be used.
c) Terms like “brittleness is large” needs to be replaced by “high brittleness”
d) Most of the sentences need to be shortened, and linking is only be used in proper places. For instance, this sentence needs to be divided to two separate sentences “Figure 3 shows SEM images of the cross-sections of Si3N4/Ht250 joint joined by Ti/Cu/Kovar/Cu/Ti interlayer, and the interface is free of defects such as holes and cracks.”
Therefore, re-writing the manuscript by a native English speaker is strongly suggested.
2- In the “Materials and method” section, the procedures and the parameters used in this work, should be reported rather than giving general instructions without any details.
3- The purpose of the study is not explained in “introduction” section, while it is given in “Results and discussions” section.
4- Figure 1 is an optical microscope image? SEM image? No details are given.
5- How the chemical compositions given in Table 1 and 2 are obtained?
6- No details for SEM and EDS (Energy, Source, ….) and mechanical properties characterization (Hardness and Shear-strength measurements) are given.
7- It is claimed that SEM is used to analyze the mechanical properties of the joints. How?!! SEM is not a mechanical analysis technique!!!
8- The authors have given strong statements about chemical analysis from a SEM image (Figure. 3). SEM imaging is not an elemental analysis technique. Authors should provide elemental analysis profile along the scanned area by EDS for this purpose.
9- The legends of the figures and the labels for the axes are very small and fuzzy, making them difficult to read. The quality of the graphs, is not high enough for any publication.
10- EDS provides only the elemental abundancy and it is not enough to get the composition of the compounds with high certainty (For example claiming TiC existence in Figure 4). XPS should be carried out for this purpose to find possible compositions using oxidation state of elements and their abundances.
11- The elemental analysis data provided using EDS are given with 2 decimal places and without any uncertainty boundary. EDS is not very high accurate elemental analysis technique, and the current format of data reporting is not acceptable.
12- The authors claim that Ti atoms are concentrated in the edges of graphite flakes, however, their line scan through the graphite does not show any peak for Ti percentage when it passes the edges, twice. Moreover, if their assumption is correct and Ti atoms are concentrated on the edges of the flakes, how they can claim formation of the TiC phase? Is this phase only formed on the edges of the flakes? Existence of TiC should be proven by XPS. High resolution Raman mapping also can be used to investigate the existence of TiC in this case.
13- The reviewer is highly concerned by the lack of precision and repeatability with which results for mechanical properties are reported. How many samples were tested? What loads are used? What are the error bars?
Overall, the paper is lacking clear procedure and protocols for mechanical analysis. The claims about the chemical composition of the materials and phases are unsupported. The graphs are presented in very low quality. And the manuscript is written in very poor English.
In the view of all the points raised above, this reviewer does not suggest this manuscript publication in Ceramics, before ant major revision.
Author Response
请参阅附件。
Author Response File: 
Author Response.docx
Reviewer 2 Report
The authors presented deposition of composite diffusion bonding of Ti/Cu/Kovar with Si3N4/Ht250. Method seems reasonable and results are well presented and discussed with evidences.
Bonding durability in terms of fracture toughness, wear and impact must be carried out to demonstrate the efficacy of this composite interlayer coating. The authors must comment on this in discussion or limitations of the paper.
In Materials and method section, one sentence cannot be a paragraph. Consider merging them into a big para.
References in Introduction section are merged into the sentence. This must be fixed. It seems the authors did not check formatting before submission.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Ti/Cu/Kovar multi-layer interlayer PTLP diffusion bonding Si3N4/Ht250
Overall, good paper, comprehensive, and has been structured well. However, I have some remarks mentioned below to improve the manuscript further.
- The novelty of the work was not stated well. What is new in this work that other articles didn't do? Please clarify it.
- Why authors removed the line numbering which is given in the template? It is used to facilitate mentioning where the correction is needed.
- It seems that authors have an issue with adding a space. Almost, all sentences were not separated with a space after the full stop. Please make sure that there is a space after the end of each sentence. Also, please add a space between the value and its unit (currently, all units are linked to their values).
The abbreviations should be defined when they are first mentioned (e.g., cps).
- The references were not cited properly within the text as it is different than the way of citation according to the template of Ceramics and MDPI in general (it should be between square brackets). Please check Ceramic's template again (or some already published articles) and correct it throughout the manuscript.
- Also, when referring to other researchers, only the surname remains, and there should be a dot "." after et al (i.e., Zou et al.). Fix this for all cited researchers.
- I believe that the word "researchers" are more fit to be used rather than "scholars" in the last paragraph of the Introduction chapter.
- Please provide the manufacturer (company and country) of all equipment used (in the Materials and Methods chapter).
- Please make the "t" of Ht250 uniform, either always capital or small letter, it was mixed up.
- Some subfigures were not given a title or letter to recognize them (e.g., the left subfigure in Figure 3). It should be highlighted with a notation letter (i.e., (a)), otherwise how could you refer to it?
- The title of x and y axes is missing in Figure 5 (graphs at the right side).
- I believe that the sentence "on PTLP diffusion joins at the Si3N4/Ti/Cu/Ko-var/Cu/Ti/Ht250 interface" written in the subheadings 3.2.1. and 3.2.2. is redundant/repeated because it was already mentioned in the heading 3.2. The same for the “on the mechanical properties of Si3N4/Ti/Cu/Ko-var/Cu/Ti/Ht250 joints” in the subheadings 3.3.1. and 3.3.2.
- The language generally is good and understandable. However, some of the punctuations are incorrect or missing. Also, there are some incomplete sentences. For instance, in page 5 “When the temperature further increased to 1000℃ ….. and the interface was completely”, or in page 10 “As shown in Figure 11, the Ht250 and Ti/Cu/Kovar/Ti/Cu intermediate …. but the morphology and transition of the interface reaction layer”, and in page 14 “it is good”!! Please take another round throughout the text and fix these things.
- The resolution of the diagrams (line scan analysis spectrum) in Figures 9, 10, and 11 is poor. It is better to improve the quality to clarify the annotations, and not to squeeze the figures.
- Figures 13 and 14: from how many measurements these values are coming? If at least three measurements, and the values given are the average, why the error bars are not shown?
- Please add (a) and (b) on the subfigures of Figure 16.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The comments have been addressed.
Reviewer 2 Report
The authors addressed the comments.
