Effect of Heat Treatment on Microstructure and Tribological Properties of Laser Cladding CeO2/Ni60 Composite Coating on 35CrMoV Steel
Round 1
Reviewer 1 Report
PAPER REVIEW COATINGS
Review of the Manuscript ID: COATINGS 12-01575-v2 entitled “Effect of Heat Treatment on Microstructure and Tribological Properties of Laser Cladding CeO2/Ni60 Composite Coating on 35CrMoV Steel” by Zhiming Gao, Shuqing Zhang, Zhongtang Gao, Haibo Ren and Chuanwei Zhang submitted to the journal of Coatings.
In this paper, the authors prepared a Ni60 cladding layer with an addition of 6.0% CeO2 on 35CrMoV steel by laser cladding and heat treated them at 500, 600, and 700ºC for one hour to explore the effect of heat treatment and tribological performance of such coatings. The authors indicate that the coating microstructure grains are refined, the uniformity is significantly improved at 500℃, and wear resistance by 43%.
This reviewer has some observations for the authors.
The first and main concern for this work is that the paper below, written by other authors, is not cited in the references, but it contains some identical figures (see figures 1, 2, and 8 b) of the paper below) and describes a similar study.
Suppose that is some previous work from which the present paper was based. In that case, it is suggested to elaborate the results considering that reference and highlighting the main differences and contribution of the work to be considered for publication.
Second, the authors imply that 500ºC is the optimum temperature for heat treatment but what happens at temperatures lower than that?
Effects of Thermal Treatment on Microstructure and Wear Properties of Ni60/CeO2 Composite Coating 35CrMoV Steel by Laser Cladding by Jianbo Liu, Xiaohui Li, Jing Bai, Tong Zhang, Yunhua Xu and Yuan Yu
Coatings 2022, 12, 1575. https://doi.org/10.3390/coatings12101575
Reviewer suggestion: A major revision is needed.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript presents the results of original experimental studies of the tribological and wear-resistant properties of the Ni60/6.0% CeO2 cladding layer on 35CrMoV steel, obtained using laser cladding technology. The manuscript presents new data on the macroscopic morphology, microstructure, phase composition, microhardness, friction coefficient and wear rate of coatings after annealing coatings at temperatures of 25, 500, 600 and 700 C. Analysis of data showed that the coating layer obtained on the basis of Ni60 with 6.0% CeO2 consists of components γ-(Fe,Ni),Cr7C3,Cr23C6,CrB, CrFeB and Cr2Ni3. Hard phases such as Cr7C3, Cr23C6 and CrB significantly increase the hardness and brittleness of coatings. It was found that annealing of the coating at a temperature of 500 C is accompanied by the formation of a fine grained microstructure in the layer. Coating after annealing at 500C achieves the best friction and wear characteristics. The wear resistance of the composite coating at annealing temperature of 500°C decreased by 43% compared to the coating without annealing.
The manuscript is well structured. Quality of illustrations is high.
The conclusions are specific and based on the assessment of the authors of the obtained original experimental results.
The results obtained may be of interest to a wide range of specialists, graduate students and researchers carrying out research in the development of laser technologies for applying wear-resistant coatings on steel products.
The manuscript needs improvement.
1) The manuscript should be supplemented with information on the equipment for annealing.
2) It is necessary to describe in more detail the temperature-time parameters of the annealing processes that were used in the preparation of samples for tribotechnical tests (section2.3). The accuracy of the determination and the method of controlling the temperature maintenance during annealing of the samples require clarification. The rate of heating and cooling of coated samples should be specified.
3) The manuscript should be supplemented with information on the equipment for tribotechnical testing.
4) Information about used counterbody should be indicated when determining the coefficient of friction, as well as during wear tests. It is necessary to specify the linear speed of the relative movement of the sample relative to the counter body.
5) It is necessary to supplement subsection 3.5 with information about the equipment used for measuring microhardness and indentation modes for determining microhardness (values ​​of load, indentation time).
6) The title of subsection 3.5 should be changed. The title of the subsection "Microhardness of hardness" is not correct.
7) The publication details should be clarified in the citation list [1] (Journal of Materials Engineering and Performance, 2022 Volume 31, Issue 11, p.9534-9543).
8) An editorial revision of the list of references is required to remove double serial numbers of cited publications.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Round 2
Reviewer 1 Report
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