Investigation of the Effect Chloride Ions on Carbon Steel in Closed Environments at Different Temperatures
Round 1
Reviewer 1 Report
The authors should explain why did they think important the investigation of the metal sample in the humid environment over NaCl solution.
How do the authors explain the expressions found in several places in the text: “Error! Reference source not found.”
It would be necessary to give more information about the Clark’s solution, described in [14].
Page 3 line 138: Hoe do the authors explain: “…polished to 4μ using 1200 grit SiC abrasive paper.”
Please, give more information about: „…specimens were coated with electrodeposition technique”.
Please, explain the equation (2). In eq. (3) correct the word “corrosion”.
Page 5 line 165. ‘The loss of metal increases over time; and the concentration of the ionic species and temperature accelerate the corrosion process.” These experiments show the corrosion rate at a chosen (3.5%) NaCl concentration.
How do the authors explain the situation shown in Figure 1 (d) : carbon steel surface morphology “liquid phase (25 oC to 80 oC)”. Not any pits are visible, the surface is smoother than that one measured in the gas phase.
Page 7 line 206 : “the samples exposed to immersion conditions were subjected to uniform corrosion.” Generally, the metals suffer pitting corrosion under the given condition the authors described. How do the authors explain this statement?
It is necessary to mention the pH values of the test solution at the beginning, not only after the corrosion tests (page 10 line 273). It is mentioned that the pH value decreased during the corrosion but the equations 4-10 do not give explanation on this observation.
Figure 11 and 12: Please, explain why are here for the cycling ”22oC to 80 oC” and in any other experiments “25 oC to 80 oC”
Author Response
Dear reviewer,
I would thank you for your time and consideration to improving the manuscript. I want to inform you I have attached two files; one is the manuscript, and the other is the summary of responses to reviewers. If there are any errors in references or disorganisation in diagrams, please let me know because I downloaded pdf files on my device, and it didn't appear to me any of these issues.
I would like to thank you again for your recommendations to help us improve the manuscript.
Kind regards,
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The reviewed paper describes interesting corrosion studies of unalloyed steel in an aqueous environment at elevated temperature. Many measurement methods were used in the measurements to increase the amount of information obtained. Unfortunately, it must be said that the work is written very carelessly. Occurring errors are so significant that they do not allow to publish this work in the current version. Here is the error list:
- no correct citations of literature, the message: Error! Reference source not found
- illegible descriptions to the photos in Figure 9
- errors in intervals, e.g.: 80° C, or Cl -
- Fig. 14a superimposed internally
- Some drawings have been stretched too much, e.g. Fig 6c
- Excessive shifts between paragraphs - eg mathematical and chemical equations
Content errors.
In water environments, the mechanism of corrosion in the CO2 environment is very important, this aspect was completely omitted in the work. The pH of the water environment in the tests was 5.2, which is the result of the dissolution of CO2 in water. Many analyzes indicate that the dominant corrosion mechanism is not corrosion in the environment of dissolved oxygen in water, but as a result of the presence of CO2, an example is, for example, the analysis of water corrosivity based on corrosion aggressiveness indexes (Langelier, Ryznar index).
For some studies, it is sometimes difficult to assess their usefulness. For example, electrochemical noise (ECN) tests were performed in a gaseous environment. It should be noted that the measurement of electrochemical noise is an electrochemical test in which an aqueous environment must be present. The results of the presented research may in some cases be completely wrong, the conclusions do not bring much to the results of research at work.
There is no correlation between the obtained tests, e.g. it is possible to compare gravimetric results with EIS, it is possible to determine the corrosion rate from the value of the charge transfer resistance of the EIS measurement.
The concept of pitting corrosion applies only to the mechanism of construction materials with passive layers, e.g. stainless steels, aluminum alloys. In this case, this mechanism can rather be described as local corrosion.
The work does not specify the composition of the condensate, whether chloride ions are present in it.
Author Response
Dear reviewer,
I would thank you for your time and consideration to improving the manuscript. I want to inform you I have attached two files; one is the manuscript, and the other is the summary of responses to reviewers. If there are any errors in references or disorganisation in diagrams, please let me know because I downloaded pdf files on my device, and it didn't appear to me any of these issues.
I would like to thank you again for your recommendations to help us improve the manuscript.
Kind regards,
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Corrections have been made in the work, I have no comments at the moment
