Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors present a method for polishing the inner surfaces of components, which appears to be related to the focused ion beam (FIB) technique found in SEM systems. I do not have major revisions for the manuscript other than:

1) lines 194 - 203: the authors may wish to simply report the final important numerical values. The intermediate values make it clumsy to read.

2) line 293: I suggest the authors to reformat their conclusion in a paragraph form and perhaps add a remark on future directions of this technique.

Author Response

Comments 1. lines 194 - 203: the authors may wish to simply report the final important numerical values. The intermediate values make it clumsy to read.

We agree with you and excluded intermediate values in lines 193, 194 and line 200.

Comments 2. line 293: I suggest the authors to reformat their conclusion in a paragraph form and perhaps add a remark on future directions of this technique.

At your suggestion, we have added a paragraph before the Conclusions section regarding the future application of this methodology.

Thank you for your attentive reading of our manuscript.

With best regards,

A. Metel

Reviewer 2 Report

Comments and Suggestions for Authors

As comments on the content, can be mentioned the following:

1. On page 6, the design of the experimental installation is considered. Up to page 7, the authors write about ions and gas feed without mentioning the gas itself. And only further it is mentioned that it is argon. In this case, the reader may have some misunderstanding of the material – a fair question is what kind of gas and ions are these? It is better to specify the type of gas at the very beginning of the description.
2. On page 7 it is stated that fast neutral atoms are obtained as a result of charge exchange on a gas target. In recent years, sources of accelerated neutral particles with charge exchange on a solid-state target have become widespread, which are often characterized by better performance. To improve the perception of the material, authors should provide some justification for their chosen source design.
3. Also on page 7, the calculation using the formula (2) of the material removal rate is given. The flow of ions is repeatedly mentioned in the description of the calculation, however, in the case of the considered work, the material is removed by a flow of accelerated neutral particles. Authors should clarify how legitimate it is in this case to use the formula for the ion flow for calculations.

Also should be mentioned a few comments on the design and presentation of the material:

1. In the first part of the work, a hyphen is used to indicate ranges of values (“cone apex is 40-50°, and its length  is 1˗1.5  times greater”), followed by a dash in the last part of the work (“voltage of Ud = 200–400 V is applied”). There should be some kind of uniformity.
2. On page 9, the description uses the word “disc” first, and then “disk” later. In this case, the reader is again confused about what the authors mean. It is worth coming to a monotonous designation.
3. On page 10, there is a line “low values of Ra = 0.017 μm, Ra = 0.011 μm, Ra = 0.006 μm and Ra = 0.0043 μm” that would be better rewritten in a different form. For example “low values of Ra: 0.017, 0.011, 0.006 and 0.0043 μm”.
4. On page 11, the roughness parameter is given in nanometers, although in all other cases it was previously specified in micrometers. Again, it is better to do it uniformly.

Author Response

Comments 1. On page 6, the design of the experimental installation is considered. Up to page 7, the authors write about ions and gas feed without mentioning the gas itself. And only further it is mentioned that it is argon. In this case, the reader may have some misunderstanding of the material – a fair question is what kind of gas and ions are these? It is better to specify the type of gas at the very beginning of the description.

At your suggestion we specified the type of gas – argon. Wherever possible, we have replaced the word "gas" with "argon", except “gas turbines” and “gas feed device”.

Comments 2. On page 7 it is stated that fast neutral atoms are obtained as a result of charge exchange on a gas target. In recent years, sources of accelerated neutral particles with charge exchange on a solid-state target have become widespread, which are often characterized by better performance. To improve the perception of the material, authors should provide some justification for their chosen source design.

At your suggestion we added in the revised manuscript the following justification:

Focusing a beam of fast neutral atoms is impossible. A concave accelerating grid was used to generate an intense beam of fast argon atoms with a cross-sectional diameter of 5 mm. Accelerated ions begin moving from the grid toward its focus and, due to charge exchange collisions, are converted into fast neutral atoms along the way. Generation of a beam capable of entering a die with a working channel diameter of 5 mm owing to charge exchange on the solid target is impossible.

Comments 3. Also on page 7, the calculation using the formula (2) of the material removal rate is given. The flow of ions is repeatedly mentioned in the description of the calculation, however, in the case of the considered work, the material is removed by a flow of accelerated neutral particles. Authors should clarify how legitimate it is in this case to use the formula for the ion flow for calculations.

It is well-known, that sputtering coefficients for fast atoms and their ions with equal kinetic energy are equal. Therefore, the use of the formula for the ion flow in the case of fast atoms is well legitimate.

Also, should be mentioned a few comments on the design and presentation of the material:

Comments 1. In the first part of the work, a hyphen is used to indicate ranges of values (“cone apex is 40-50°, and its length  is 1˗1.5  times greater”), followed by a dash in the last part of the work (“voltage of Ud = 200–400 V is applied”). There should be some kind of uniformity

In the revised manuscript we changed dashes for hyphens.

Comments 2. On page 9, the description uses the word “disc” first, and then “disk” later. In this case, the reader is again confused about what the authors mean. It is worth coming to a monotonous designation.

We are sorry for this negligence. In the revised manuscript we left only “disk”.

Comments 3. On page 10, there is a line “low values of Ra = 0.017 μm, Ra = 0.011 μm, Ra = 0.006 μm and Ra = 0.0043 μm” that would be better rewritten in a different form, for example, low values of Ra: 0.017, 0.011, 0.006 and 0.0043 μm”.

We have done as you advised.

Comments 4. On page 11, the roughness parameter is given in nanometers, although in all other cases it was previously specified in micrometers. Again, it is better to do it uniformly.

We have done so, thank you.

 

Thank you very much for your valuable suggestions.

With best regards,

Alexander Metel