Electron-Beam Processing of Aluminum-Containing Ceramics in the Forevacuum Pressure Range
Round 1
Reviewer 1 Report
The paper shows electron-beam processing of aluminum-containing ceramics in the forevacuum pressure range. Generally, the paper is well-written.
Comments on the paper:
- abstract should be improved. The abstract is too general. It should be improved and include more specific details regarding the aim of the work, procedures (research methodology), obtained results and main findings. Place the question addressed in a broad context and highlight the purpose of the study; Describe briefly the main methods or treatments applied; Results: Summarize the article's main findings; and; Conclusion: Indicate the main conclusions or interpretations. The abstract should not contain any undefined abbreviations or unspecified references. Please see journal instructions for authors.
- table 2 - should be given is it wt% or at%.
- What was the porosity in relation to similar materials?
- The hight Y-axis in fig 6 should have the same max range.
-
I suggest a minor revision.
Author Response
The paper shows electron-beam processing of aluminum-containing ceramics in the forevacuum pressure range. Generally, the paper is well-written.
Comments on the paper:
Point 1: Abstract should be improved. The abstract is too general. It should be improved and include more specific details regarding the aim of the work, procedures (research methodology), obtained results and main findings. Place the question addressed in a broad context and highlight the purpose of the study; Describe briefly the main methods or treatments applied; Results: Summarize the article's main findings; and; Conclusion: Indicate the main conclusions or interpretations. The abstract should not contain any undefined abbreviations or unspecified references. Please see journal instructions for authors.
Response 1: We have made changes to the article:
Abstract: Aluminum-ceramic materials based on A12O3 and AlN are widely used in the electronics industry and, according to a number of electrophysical and technical and economic parameters, are among the most suitable for the production of electrical and radio engineering products. In this study, it is shown that the treatment of ceramics based on A12O3 with an electron beam with a power of 200-1100 W and a current of 10-50 mA leads to heating of the ceramic surface to a temperature of 1700 C. When heated to a temperature of 1500 ° C and kept at this temperature for no more than 10 seconds, an increase in the roughness of the ceramic surface is observed by more than an order of magnitude. At the same time, for ceramic substrates based on aluminum nitride, an increase in the temperature of electron beam treatment from 1300 to 1700 C leads to an increase in thermal conductivity from 1.5 to 2 times. The edge angle of water wetting of the AlN surface can vary from 20 to 100 degrees depending on the processing temperature, which allows you to control the transition of the material from a hydrophilic to a hydrophobic state. At the same time, electron beam exposure to Al2O3 does not change the wettability of this material so much. Electron beam processing in the forevacuum pressure region allows controlled changes in the electrophysical properties of ceramic materials based on A12O3 and AlN.
Point 2: Table 2 - should be given is it wt% or at%
Response 2: We have made changes to the article:
Table 2. Elemental composition of original (unirradiated) substrates, at%.
Point 3: What was the porosity in relation to similar materials?
Response 3: The porosity of the non-irradiated substrates did not exceed 1%, which corresponds to the results of other researchers. On page 2 we added this information:
Point 4: The hight Y-axis in fig 6 should have the same max range.
Response 4: The roughness of the ceramics after processing differs 100 times from the non-irradiated one, therefore, a different scale of the Y axis is applied
Reviewer 2 Report
In their manuscript A. Klimov et al. use electron bombardment to modify the surface morphology and chemistry of Al-containing ceramics (Al2O3 and AlN). The manuscript is clearly written and results are well justified on the basis of different experimental tests, including SEM, XRD, contact angle, conductivity, profilometry. Conclusions are well supported by the experiments. For these reasons the work in my opinion can be published.
Author Response
Thank you for carefully reading the article.
Reviewer 3 Report
Please refer to the attached file
Comments for author File: 
Comments.pdf
Please see the attached file.
Author Response
Point 1: Fig.3: please elaborate more in last paragraph of page 4 on how you control the cooling down stage such its cooling profile is linear instead of an exponential decay, if the heating source is suddenly withdrawn.
Response 1: Cooling, as well as heating, is carried out due to a linear decrease in the power of the electron beam. We did not observe a sudden failure of the source.
Point 2: Pls revise line 142: there are 2 “by” in one line.
Response 2: We have made changes to the article (line 152):
The surface temperature increase was achieved by gradually increasing the beam current at constant beam accelerating voltage in the range 14–16 kV depending on the type of ceramic.
Point 3: Thermal conductivity of Al2O3 in Line 159 is 30 W/(m·K), 50% higher than the 20 W/(m·K) (Table 1). Please standardize it.
Response 3: We have made corrections to the table 1:
Table 1. Substrate parameters [42-44].
|
Parameter |
Policor (Al2O3) |
INC-AN180 (AlN) |
|
Content, % |
99.7 |
96 |
|
Density, g/cm3 |
3.96 |
3.3 |
|
TCLE, 10-6/℃ |
8 |
4.8 |
|
Thermal conductivity, W/m·K |
30 |
160-180 |
|
Dielectric constant (at 20 ℃) |
9.45 ~ 9.95 |
9 |
|
tan δ, 10-4 |
1 |
5 |
|
Melting point, ℃ |
2072 |
2200 |
Point 4: Line 214: lower melting point is not due to presence of focused electron beam but due to the vacuum condition.
Response 4: We agree with the reviewer's opinion.
Point 5: Line 217-218: “during the short time when the beam stops”, there is no further heating of the sample but just conduction of heat from surface to bulk as well as dissipation of heat from surface to surrounding environment.
Response 5: That's right. When the electron beam stops, the surface at the point of impact of the electron beam heats up more than 1500 degrees and the temperature can reach the melting point.
Point 6: Line 218-222: presence of pore could also due to evaporation of oxygen from Al2O3.
Response 6: That's right. We have added text on page 8.
The presence of pores in the surface layer is connected with the process of their creation and growth in a thin layer of the melt due to the presence of gas-forming elements, which can evaporate (mainly of oxygen, which is a ceramic constituent and which is released during oxide dissociation).
Point 7: Line 238: “increases by a factor of several” → “increases by several factors”
Response 7: We have added text on page 8.
As can be seen, with increase in surface temperature, the roughness increases by several factors.
Point 8: Table 2& 4: at% or wt%? 1 decimal place instead of 3 decimal place?
Response 8: We have made corrections to the table 2 and 4.
Table 2. Elemental composition of original (unirradiated) substrates, at%.
|
|
Nitrogen |
Oxygen |
Aluminum |
Yttrium |
|
AlN |
24.2 |
25.5 |
44.8 |
5.5 |
|
Al2O3 |
- |
54.7 |
45.3 |
- |
Table 4. Elemental composition of different regions of irradiated AlN ceramic, at%
|
|
Nitrogen |
Oxygen |
Aluminum |
Yttrium |
|
I |
24.2 |
25.5 |
44.8 |
5.6 |
|
II |
41.6 |
6.6 |
52.0 |
0.3 |
|
III |
0 |
60.6 |
11.5 |
27.9 |
|
IV |
0 |
21.4 |
65.8 |
12.0 |
Point 9: Scale bars in SEM images need be redrawn in order to see them clearly. Many of the default scale bars are discernible (For example, Fig. 1(b), 8(b))
Response 9: We have made corrections to the fig. 1 and 8.
Figure 1. SEM surface images of original substrates: a – Policor (Al2O3), b – INC-AN180 (AlN).
|
Figure 8. Formation of aluminum-yttrium structure on the AlN surface processed at a temperature of 1500 °С (а) and 1700 °С (b). |
|
Point 10: “I” is missing from Table 4. Fig. 9 is an illustration of Table 4 without any additional infor. The author can keep ether one of them and remove the other one.
Response 10: We will save both the table and the figure. It's convenient for the reader.
Point 11: Fig. 12: what does the line 1 and 2 stand for?
Response 11: We have added text on page 14
Figure 12. Dependence of thermal conductivity on processing temperature. The temperature at which the measurements were carried out: 1 – 50 ° C, 2 – 500 ° C.
