The Model for Estimating the Failure Mechanism of Tensioned Plasma-Sprayed Zirconia Ceramic Hard Coating
, Kristine Carjova 3,*, Leonid Vinogradov 4, Olexandr Melnychenko 2, Janis Brunavs 3, Sintija Girgensone 3, Janis Baronins 3 and Lilit Zakoyan 3
Round 1
Reviewer 1 Report
The authors reported the manuscript entitled "The model for estimating the failure mechanism of tensioned plasma-sprayed Zirconia ceramic hard coating". Work organization and presentation is good.
However, there are few complex sentences in the manuscript. Ex: "An analytical method was used to determine the normal stresses in the coating and the shear stresses at the interfaces between the substrate and the adhesion promoter and between the adhesion promoter and the coating layer". It is advised to rewrite the complex sentences in a simple manner for better understanding of the readers.
In addition, some sentences were repeated in abstract and conclusion. It is advised to rewrite the abstract and conclusion in scientific manner.
Author Response
Dear reviewer,
Thank you for your valuable contribution in this article.
> 1. The authors reported the manuscript entitled "The model for estimating the failure mechanism of tensioned plasma-sprayed Zirconia ceramic hard coating". Work organization and presentation is good.
Answer: Thank you for your evaluation. It's nice to hear such an assessment and we did our best to improve our article according to comments and objective criticism.
> 2. However, there are few complex sentences in the manuscript. Ex: "An analytical method was used to determine the normal stresses in the coating and the shear stresses at the interfaces between the substrate and the adhesion promoter and between the adhesion promoter and the coating layer". It is advised to rewrite the complex sentences in a simple manner for better understanding of the readers.
Answer: Thank you for your indications. We have rechecked whole work and improved the writing style regarding your comment and comments made by another reviewer.
>3. In addition, some sentences were repeated in abstract and conclusion. It is advised to rewrite the abstract and conclusion in scientific manner.
Answer: Thank you for your indications. We have rewritten these sentences in more scientific manner.
Best regards,
PhD Janis Baronins
Latvian Maritime Academy
Reviewer 2 Report
This paper investigated the theoretical model for estimating failure mechanism of tensioned plasma-sprayed Zirconia ceramic hard coating. The research topic is of interest; however, this paper cannot be accepted in its current state, needing some revisions.
(1) The introduction does not clearly state the necessity and contribution of this research.
(2) Section 2.2. What were the test conditions, including loading rate, instrumentation, etc.?
(3) Section 3.2. Figure 3 shows the calculated results based on the theoretical equations. How did the author validate the accuracy of the calculated results? Were the calculated results compared with the test results?
(4) In the conclusions, future research should be emphasized.
Author Response
(1) The introduction does not clearly state the necessity and contribution of this research.
Answer: Thank you for your indication. The required statement is added in new version.
The following sentences are added to the introduction section.
"Ceramic hard coatings fracture by different mechanisms in service and under testing conditions. The authors studied the fracture mechanism of a hard coating under tensile loading on a metal substrate."
"The proposed approach allows evaluating the nature and damage features of two-layer coatings in ambient and corrosive maritime environments."
(2) Section 2.2. What were the test conditions, including loading rate, instrumentation, etc.?
Answer: Thank you for your question. The additional description about setup and conditions is added.
The following sentences are added to the introduction section.
Section 2.1.: "The operator performed tensile testing at ambient temperature. Strain gauges measured the strains on the surface of the specimens. The tensile process of the specimens was done intermittently. The device detected the failure of the coating by monitoring strain gauge indication drops."
(3) Section 3.2. Figure 3 shows the calculated results based on the theoretical equations. How did the author validate the accuracy of the calculated results? Were the calculated results compared with the test results?
Answer: The calculation of the stress state in specimens with coatings is a very difficult task. In the paper of the author of the article (see ref. 46) a detailed analysis of existing models for calculating stresses in the coating is given. These models were structured into six types. The accuracy of these models varies. The most common is the Agrawal-Raj model (ref. 45). The number of citations of this model reaches 316 (according to the Scopus database.) However, this approximate model does not take into account the concentration of interface shear stresses in the vicinity of the free edge of the coating. More accurate models are based on the shear lag model. A modification of this model for a two-layer coating is presented in this work. The accuracy of this analytical model was verified by comparison with numerical simulations both the authors of the article and other researchers. See for example.
- Dolgov, N., Vinogradov, L., Blumbergs, I., Chatys, R. (2022). Calculation of the Stress State in Coatings by Analytical and Numerical Methods Considering Thermal Loads. In: Lesiuk, G., Duda, S., Correia, J.A.F.O., De Jesus, A.M.P. (eds) Fatigue and Fracture of Materials and Structures. Structural Integrity, vol 24. Springer, Cham. https://doi.org/10.1007/978-3-030-97822-8_2
- Dikova, T., Vasilev, T., & Dolgov, N. (2019). Failure of ceramic coatings on cast and selective laser melted Co-Cr dental alloys under tensile test: Experiment and finite element analysis. Engineering Failure Analysis,105, 1045-1054. https://doi.org/10.1016/j.engfailanal.2019.07.018
Tensile tests of coated samples showed the occurrence of cracks in the coating in accordance with the proposed model.
No changes are made in the new version of the paper.
(4) In the conclusions, future research should be emphasized.
Answer: Thank you for your suggestion.
The following sentence is added to the conclusions section.
"In the future, it is planned to study the influence of the adhesion strength of layers on the mechanism of destruction of two-layer coatings."
Best regards,
Janis Baronins
Reviewer 3 Report
I can recommend the publication of the manuscript after a minor revision.
Write in alphabetical order the keywords.
Lines 57-58: insert more details.
Lines 112-115 are identical to lines 115-118, but they have different references. Please, erase one of them and clarify.
“One of the most important reasons for the breakdown and failure of technological elements is the cracking of the hard coating in flakes and delamination from the substrate or adhesive layer under the applied operating conditions [31].”
“One of the most important reasons for the breakdown and failure of technological elements is the cracking of the hard coating in flakes and delamination from the substrate or adhesive layer under the applied operating conditions [32].”
Lines 152-154: insert the main characteristics of the tensile testing machine (or a reference).
Line 180: how many samples were used in experiments?
Line 184: can you specify other surface texture parameters, such as a) Height parameters: Root mean square height Sq [nm]; Skewness Ssk [-]; Kurtosis Sku [-]?
The writing can be improved, it is still poor with numerous typos, or grammar mistakes (e.g. line 206, and so on).
Figs. 3 and 4. Use a reasonable font text size inside the figure to read the figure clearly.
Line 228: insert more details.
Lines 252-254: Please insert technical values to support your statement.
Lines 303-307, 307-310: Insert corresponding references.
Line 331, 337-338 must be deleted.
Specify the limits of this study. State the respective advantages and disadvantages.
Insert Data Availability Statement.
Insert in References some articles that fit in this field published in “Coatings” journal, MDPI.
References are not written according the Guide of Authors (e.g., ref. [5], [9], [15], [16], [27], and so on).
This paper presents an interesting approach and deserved to be published after the mentioned revisions.
Author Response
Dear reviewer,
Thank you for your evaluation. It's nice to hear such an assessment and we did our best to improve our article according to comments and objective criticism.
> 1. Write in alphabetical order the keywords.
Answer: Thank you for your indication. Keywords are sorted alphabetically.
Keywords: Adhesion layer; delamination; fracture mechanism; hard coating; shear stress; stainless steel; tensile test.
> 2. Lines 57-58: insert more details.
Answer: Thank you for your suggestion. We have added additional sentence.
“These materials can be magnets containing devices or elements, residual metal particles from cutting or welding processes (industrial waste) [7], ferrofluids [8], etc., which otherwise can contaminate cargo tanker walls.”
> 3. Lines 112-115 are identical to lines 115-118, but they have different references. Please, erase one of them and clarify.
“One of the most important reasons for the breakdown and failure of technological elements is the cracking of the hard coating in flakes and delamination from the substrate or adhesive layer under the applied operating conditions [31].”
“One of the most important reasons for the breakdown and failure of technological elements is the cracking of the hard coating in flakes and delamination from the substrate or adhesive layer under the applied operating conditions [32].”
Answer: Thank you for your indication. Repeated sentence is erased.
> 4. Lines 152-154: insert the main characteristics of the tensile testing machine (or a reference).
Answer: Thank you for your demand. The main one of main characteristics is added (“for forces up to 10 kN and loading rates from 10 up to 90 mm·min-1”).
“A standardized computer-controlled Instron tensile testing machine (for forces up to 10 kN and loading rates from 10 up to 90 mm·min-1) performed the strain tests and provided comparability of the test results.”
> 5. Line 180: how many samples were used in experiments?
Answer: Thank you for your question! Three (3) specimens were tested, and one used for control needs. The clarification is added to the text
“The operator produced samples of two-layer coatings with the help of plasma spraying on flat metal specimens. First, an operator prepared and tested three specimens and prepared one specimen for results control needs.”
> 6. Line 184: can you specify other surface texture parameters, such as a) Height parameters: Root mean square height Sq [nm]; Skewness Ssk [-]; Kurtosis Sku [-]?
Answer: Thank you for your important question. Unfortunately, our operator forgot to record these parameters additionally to the Ra. We will not risk making repeated measurements from damaged specimens. We apologize for this shortcoming.
> 7. The writing can be improved, it is still poor with numerous typos, or grammar mistakes (e.g. line 206, and so on).
Answer: Thank you for your indication. The text is improved in the whole article, and corrections are made.
> 8. Figs. 3 and 4. Use a reasonable font text size inside the figure to read the figure clearly.
Answer: Thank you for your indication. The font size in figures 3 and 4 are made larger.
> 9. Line 228: insert more details.
Answer: Thank you for your demand. The additional details are added.
“A concentration of shear stresses occurs in the vicinity of the free edge of the coating. With increasing distance from the free edge of the coating, the stress singularity reduces. The maximum shear stresses cause edge detachment of the top layer of the coating because of shear strains in the interface between the top ceramic coat and the metal bond coat.”
> 10. Lines 252-254: Please insert technical values to support your statement.
Answer: Thank you for your demand.
The authors of the cited article didn’t express this conclusion with numerical values but with the help of equations for mathematical model. No improvements are made in the text.
- 61. Dolgov, N.A.; Lyashenko, B.A.; Rushchitskii, Ya.Ya.; Veremchuk, V.S.; Terletskii, V.A.; Kovalenko, A.P. Effects of Differ-ences in Elastic Characteristics between Substrate and Coating on the Stress and Strain State in a Composite. 1. Estimating Tensile Stresses in the Coating. Strength of Materials 1995, 27, 525–530, doi:10.1007/BF02208570.
> 11. Lines 303-307, 307-310: Insert corresponding references.
Answer: Thank you for your indication. Corresponding reference inserted.
- Zeybek, Ö. The Stability of Anchored Cylindrical Steel Tanks with a Secondary Stiffening Ring. International Journal of Pressure Vessels and Piping 2022, 198, 104661, doi:10.1016/j.ijpvp.2022.104661.
> 12. Line 331, 337-338 must be deleted.
Answer: Thank you for your indication.
The empty line 331 is deleted in new version.
The explanatory text from lines 337-340 are deleted.
> 13. Specify the limits of this study. State the respective advantages and disadvantages.
Answer: Thank you for your suggestion.
The model for stress calculations adequately describes the stresses in relatively thick coatings. It is based on the shear lag model. Our model is characterized by all the advantages and disadvantages of the shear lag model. We have carried out a two layer coating test in the paper. The model adequately described the failure mechanism of the two-layer coating. More detailed discussion will be provided in next articles about similar research results made by authors.
> 14. Insert Data Availability Statement.
Answer: Thank you for your indication. The “Data Availability statement: Not applicable” is provided.
> 15. Insert in References some articles that fit in this field published in “Coatings” journal, MDPI.
Answer: Thank you for your suggestion. Several additional articles added from MDPI journal “Coatings”:
- Li, H.; Cui, C.; Cai, J.; Zhang, M.; Sheng, Y. Utilization of Steel Slag in Road Semi-Rigid Base: A Review. Coatings 2022, 12, 994, doi:10.3390/coatings12070994.
- Goncalves Dos Santos, A.; Montes-Ruiz Cabello, F.J.; Vereda, F.; Cabrerizo-Vilchez, M.A.; Rodriguez-Valverde, M.A. Os-cillating Magnetic Drop: How to Grade Water-Repellent Surfaces. Coatings 2019, 9, 270, doi:10.3390/coatings9040270.
- Yang, D.; Liu, J.; Zhang, J.; Liang, X.; Zhang, X. In Situ High-Temperature Tensile Fracture Mechanism of PS-PVD EBCs. Coatings 2022, 12, 655, doi:10.3390/coatings12050655.
> 16. References are not written according to the Guide of Authors (e.g., ref. [5], [9], [15], [16], [27], and so on).
Answer: Thank you for your indication. We have used Mendeley Desktop with Mendeley Cite. Unfortunately, the original DOI database contains capital letters in many fields (Name, Surname, title, etc.). We have corrected these fields in our system, but we are not 100% sure that these fields will not be autocorrected back to the DOI database version.
Best regards,
PhD Janis Baronins
Latvian Maritime Academy
