Preparation and Characterization of B4C-HfB2 Composites as Material for High-Temperature Thermocouples
Round 1
Reviewer 1 Report
The article is very well written and work being done is useful. Experimental procedures and analysis are also valid. I have made some modifications and comments as marked in the PDF. Please read the attached PDF as a reference (To the editors: you can send my modified PDF to the authors.).
In particular:
1. In Figure 3, adding a circling arrow would be helpful to explain the sintering process.
2. In the last part of the article, there are some doubt regarding to the experimental results. In Figure 8， it is better to draw the start using the absolute temperature value instead of the Delta T. Besides, what is the maximum temperature measured? This is very important because such a sensor is only significant when it can measure the very high temperatures instead of just measuring 500 K.
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Reviewer 2 Report
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Reviewer 3 Report
The authors have investigated the thermoelectric properties of B4C-HfB2 composites for thermocouples. This manuscript is well described and their experiments and results are very interesting and worthy of “Crystals”. However, the following points should be addressed before acceptance.
The Seebeck coefficients of BC30 and BC40 are almost the same, while BC20 is about double of them.However, in terms of thermoelectric voltage, BC40, BC30, and BC20 have about the same voltage difference, so it appears that thermoelectric voltage does not correspond to Seebeck coefficient. Is this difference caused by the metallic behavior, which makes the Seebeck measurement a minute voltage measurement? Or is it due to the contact resistance between the thermoelectric material(especially in B4C phase) and the electrode material (graphite foil)?
Regarding the electrical conductivity, the SEM image shows that the HfB2 phases in the BC20, BC30 and BC40 also have grown significantly, and in view of the rapid increase in conductivity, it is highly possible that the HfB2 phase is “percolating”. If possible, could the influence of percolation on electrical conduction be discussed?
Author Response
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