Effect of Heat Treatment of Martensitic Stainless Steel on Passive Layer Growth Kinetics Studied by Electrochemical Impedance Spectroscopy in Conjunction with the Point Defect Model

Round 1

Reviewer 1 Report

The article presents a study regarding the corrosion properties of martensitic stainless steel. In the reviewer’s opinion, the authors must improve the manuscript before publication (major revision).

Specific comments are given bellow:

The “Abstract” section must be rewritten.

Phrase: “Their mechanical and corrosion properties are strongly influenced by their microstructure and thereby can be affected by heat treatments.” provide the same information like the phrase: “Heat treatments like austenitizing can lead to several microstructure changes which can affect the corrosion properties on very different ways.”

Phrase: “In the present study the effect of different austenitizing temperatures on the passive film growth kinetics of martensitic stainless steel is studied by electrochemical impedance spectroscopy.” provide the same information like the phrase: “Subsequently the data was fitted by the point defect model to determine kinetic parameters and to investigate the effect of austenitizing temperature on these constants.”

Why the authors choose as experimental parameters: 2 hours for the heat treatment and 5 austenitizing temperature? Why they choose the 1000, 1050, 1100, 1150 and 1200 as austenitizing temperature? They must clarify these aspects. The electrochemical data must be correlated with the X-ray diffraction information in order to evidence the presence of other compounds in the passive layer. Thus, the authors must investigate their sample by X-ray diffraction and present and comment their XRD patterns. The authors said: “The grainsize of the material is increasing with elevated austenitizing temperature. A microscopic image of the former austenite grain size can be seen in Figure 2.” What are the estimated values for the grainsize? What the authors understand by grainsize?

They must clarify this aspect.

The images used in Figure 2 seems to be the same images from Fig. 2 in Ref. 12. The authors must clarify this aspect. Many phrases do not any sense. Ex:

“Although the influence on the different corrosion mechanism is not easy to distinguish in many cases.”

“Indicating a higher susceptibility to pitting corrosion.“

“Both indicating slower corrosion during steady state with a passivated surface.”

“In this study we used a set of 6 stainless steel samples, which differ only in heat treatment.”

In the entire manuscript the English must be checked.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The comments for the submitted manuscript entitled “How heat treatment of martensitic stainless steel influences passive layer growth kinetics – insights using the experimentally parameterized point defect model”:

Comments:

Line 8. [email protected]; The blank is missed “Correspondence [email protected]“ Line 10. Wide -> widely. Line 13. properties on very -> properties in very. Line 23. Passivity of stainless steel -> The passivity of stainless steel Line 25. underline its significance -> underline their significance Line 30. Candelaria et al. could show that with increasing austenitizing temperature up to a critical temperature the weight loss by corrosion increases. – Suggestion: Candelaria et al. showed that with increasing austenitizing temperature up to a critical temperature, the weight loss due to corrosion increases. Line 35. In a recent study Bösing et al. could show that different corrosion mechanism are affected on different ways -> In a recent study, Bösing et al. showed that different corrosion mechanisms are affected in different ways… Line 47. that the lattice distortions, …, leads to… -> that the lattice distortions, …, lead to... Line 49. Contrary to this findings -> Contrary to these findings Line 56. Point Defect Please, provide the readers with several citations on the works of Prof. D.D. Macdonald. Line 60. Please, move the acronym (PDM) to “Line 56”. Line 60. Please, choose one either “by” or “using”. Line 80. It can be assumed, that it should be “Electrochemical impedance spectroscopy measurements were performed using…” Also, replace Electrochemical impedance spectroscopy with EIS since the acronym was presented on Line 55. Line 92. differs to -> differs from Line 95. Suggestion: PVC -> Polyvinyl chloride (PVC)

 

Line 98. The sentence “Each measurement was repeated at least 3 times, and before each measurement the working electrodes were wet grinded with SiC grinding paper with a grain size of about 200 µm, degreased in ethanol and cleaned in an ultrasonic bath containing deionized water.” must be rewritten clearly.

First, the name of the electrochemical experiment must be specified. Second, the experimental repetition must have an exact number. Third, the working electrode should be named a metallic alloy sample with specifying the exact number of its working area. Forth, specify the grit range of the polished paper (“from” and “to”), not only the highest grit. Fifth, in addition to the ultrasonic bath, the samples should be rinsed by water, after dried, again rinsed/cleaned by ethanol, and then dried.

Line 101. in a standard three -> using a standard three Line 103. Suggestion: A platinum electrode served as counter, and as reference electrode an Ag/AgCl 3M KCl electrode, respectively. The investigated “NAME” samples act as working electrodes. Electrochemical potentials in this work are referred to the Ag/AgCl electrode. Line 108. which not occurs at -> which is not observed at… Line 110. Use EIS instead of Electrochemical impedance spectroscopy since its acronym was already shown above. Line 111. Potential here is to be first, time is second (at 600 mV during 1800 s). Figure 1a. The authors showed 5 reactions regarding the PDM theory; however, in the work “The history of the Point Defect Model for the passive state: A brief review of film growth aspects”, Macdonald showed 7 reactions. Both the authors' and Macdonald’s statements are about the film growth but the authors of the submitted manuscript excluded two reactions, why so? Also, the authors presented these reactions for an exact ion charge number, but it is hard to find for which metal the number belongs, assumedly is for Cr3+ but the authors need to show it clearly. Line 208. material is increasing -> material is increased Line 212. that 2 h austenitizing are sufficient -> that 2 h austenitizing is sufficient Line 2015. Therefor -> Therefore Line 262. shows - > show or showed Line 275. at the untreated sample -> in the untreated sample Line 278. The sentence formulation “…austenitizing temperature the impedance increases as well up to TA = 1100 °C” does not make sense and must be rewritten. Line 317. Which leads -> This leads Line 326. This differences -> This difference or these differences Line 327. This vacancies -> These vacancies Line 330. The sentences “We did not do this in this case for two reasons. First this model already brings a large set of parameters and we could only fit the data by making additional assumptions. That is why we does not want to increase it by adding an additional impedance element.” are written with grammar mistakes and without adhering to scientific writing rules. Please, rewrite the above. Line 332. the deviations due to the vacancies transport indicates -> the deviations due to the vacancies transport indicate Line 346. The sentence “This underlines that one need to distinguish different corrosion mechanism which are affected in different ways by the microstructure changes due to the heat treatment.” is to be rewritten. Lines 410 and 441. MacDoland -> Line 439. Concernng -> Concerning Line 425. Austenite grain size and the marteniste -> Austenite grain size and the martensite

 

Suggestion: please, reconsider the title for the paper in “more scientific way”, e.g., “Effect of heat treatment of martensitic stainless steel on passive layer growth kinetics. Point Defect Model study.” or similar.

The English language used in the paper is to be revised and improved before the subsequent manuscript submission. Please, read carefully the text before the next submission of the paper. It will allow the reviewers to focus better on the research content.

 

The manuscript must be revised and resubmitted or re-reviewing.

Author Response

We would like to thank the reviewer for these very detailed and helpful comments. We changed the manuscript according to the reviewer’s comments and suggestions.

We changed the title to a more scientific way based on the reviewer’s suggestion.

An expert for the English language proofread the whole manuscript.

Round 2

Reviewer 1 Report

In the reviewer’s opinion, the paragraph regarding the estimation of the average grain size must be reformulated before publication (minor revision). In the revised manuscript, the authors mentioned: “The former austenite grainsize of the material increases with austenitizing temperature. It was determined using the line intersect methods. The average grain size in μm was calculated from the grain size number G [33] (Figure 3).” but, most probably, the line intersect methods were applied on the optical micrographs deleted from this version. Thus, the authors must provide a comment regarding the use of the optical micrographs presented in a previous study (published in AIP Adv. 2019, 9, 065317) for the estimation of the average grain size by the line intersect methods given in this study. If this is not the case, the authors must provide the optical micrographs from which they estimated the values from the Figure 3.

Author Response

Thank you for this helpful comment. We added a clarification regarding the determination of the grain size.

Reviewer 2 Report

I reviewed the manuscript. I accept it. However, before the paper is published, the authors need to correct references 18 and 19. 18. Chao C.Y. A Point Defect Model for Anodic Passive Films. J Electrochem Soc 1981, 128, 1187. 19. Lin L.F.; Chao C.Y.; Macdonald D.D. A Point Defect Model for Anodic Passive Films. J 436 Electrochem Soc 1983, 1874–1879. These two above seem the same reference with a difference that18 contains incomplete authors' list, and 19 is copied from 18 but with the wrong year and page number. My conclusion: from two references presented, it is to be made one correct reference. Or, the authors need to check the correct name for one of the two presented references.

Author Response

Thank you for your comment. We corrected the references.