National University of Science and Technology MISiS, Moscow, Russia:

Nguyen Kuang, Postgraduate Student at the Department of Metal Forming, e-mail: nquang.misis@mail.ru
A. S. Aleshchenko, Head of the Department of Metal Forming, Associate Professor, Candidate of Technical Sciences, e-mail: judger85@mail.ru
E. R. Guseynov, Master’s Student at the Department of Metal Forming, e-mail: edikeduardguseinov@gmail.com

The present research paper aims to study the process of gas-dynamic cold spray at low pressure. The influence of surface roughness of substrate aluminum alloy A7 on the sprayed coatings porosity is also researched. The developed powder mixture A-10-1 (Al + 79.3% Al₂O₃) was used as the sprayed material. The samples surface was subjected to abrasive treatment, after that the surface roughness was evaluated using a profilometer with an estimate of the microroughness Ra ranging from 0.4 μm to 1.5 μm. The coating process was sprayed by the low-pressure cold spraying method using the DIMET 405. The working gas is compressed air, which is heated to 450 оC and accelerated by pressure. The heated flow of gas and powders impact to substrate and make a deposition. As a result of studying of the obtained coating’s microstructure by the metallographic method using SEM was found that the porosity in the sprayed coating is not low, reaches values from 0.56 to 0.89%, and rises along with increasing of surface roughness of the substrate during the coating process of A-10-1 powder mixture. The size of the pores ranging from 1 μm to 15 μm. Moreover, the orientation of the substrate roughness does not affect the quality of the coatings. The efficiency of cold spraying by the low-pressure method is measured. Due to the low contact speed and temperature during spraying, the deposition efficiency is low, in criminating to 5%.

1. Sokolov P., Aleshchenko A., Koshmin A., Cheverikin V. et al. Effect of hot rolling on structure and mechanical properties of Ti – 6Al – 4V alloy parts produced by direct laser deposition. International Journal of Advanced Manufacturing Technology. 2020. Vol. 107. pp. 1595–1603.
2. Radyuk A. G., Tilyanov A. E., Ukraintsev A. E. Forming of diffusion layers on the surface of copper and its alloys. Tsvetnye Metally. 2007. No. 5. pp. 95–97.
3. Radyuk A. G., Tilyanov A. E., Yakoev A. G., Pedos S. I. Understanding the properties of heat-treated thermal spray Zn and Zn – Al coatings on copper substrate. Tsvetnye Metally. 2005. No. 2. pp. 70–73.
4. Radyuk A. G., Titlyanov A. E., Kuznetsov V. E., Ukraintsev A. E. Study of the methods of increase of copper heat resistance and improvement of properties of copper-aluminium diffusion layer. Tsvetnye Metally. 2009. No. 6. pp. 112–113.
5. Bogdanovich V. I., Marin S. B., Dokukina I. A., Giorbelidze M. G. Development of coatings composition and equipment for repair and strengthening of power generating unit elements by plasma spraying. Tsvetnye Metally. 2016. No. 5. pp. 56–62. DOI: 10.17580/tsm.2016.05.09.
6. Alkhimov A. P., Papyrin A. N., Kosarev V. F., Nesterovich N. I. Gas dynamic spraying method of applying coatings. Patent 5302414 US. April 12, 1994.
7. Irissou E., Legoux J.-G., Ryabinin A. N, Jodoin B. et al. Review on cold spray process and technology: Part I. Intellectual property. Journal of Thermal Spray Technology. 2008. No. 17. pp. 495–516.
8. Assadi H., Kreye H., Gartner F., Klassen T. Cold spraying - A materials perspective. Acta Materialia. 2016. Vol. 116. pp. 382–407.
9. Shuo Yin. Cold spray additive manufacturing and repair: fundamentals and applications. Additive Manufacturing. 2018. Vol. 21. pp. 628–650.
10. Shkodkin A., Kashirin A., Klyuev O., Buzdygar T. The basic principles of DYMET technology. Proceedings of the 2006 International Thermal Spray Conference (Seattle, USA).
11. Kashirin A., Klyuev O., Buzdygar T., Shkodkin A. Modern applications of the low-pressure cold spray. Proceedings of the 2011 International Thermal Spray Conference, Hamburg.
12. Bobkova T. I., Deev A. A., Bystrov R. Yu., Farmakovskiy B. V. Application of wear-resistant variable hardness coatings by means of supersonic gas dynamic spray technology. Metalloobrabotka. 2012. No. 5–6. pp. 45–49.
13. Kupriyanov G. V. Restoring body parts of military machinery by cold gas dynamic spraying. Izvestiya TulGU. Tekhnicheskie nauki. 2017. No. 12. pp. 433–446.
14. Champagne V. K. The repair of magnesium rotorcraft components by cold spray. Journal of Failure Analysis and Prevention. 2008. Vol. 8, Iss. 2. pp. 164–175.
15. Villafuerte J., Wright D. Practical cold spray success: repair of Al and Mg alloy aircraft components. Materials Proceedings. 2010. Vol. 168, Iss. 5. pp. 53–59.
16. Guosheng Huang, Hongren Wang, Xiangbo Li, Lukuo Xing et al. Deposition efficiency of low pressure cold sprayed aluminum coating. Materials and Manufacturing Processes. 2018. Vol. 33, No. 10. pp. 1100–1106.
17. Maev R. G., Leshchynsky V. Introduction to low pressure gas dynamic spray. Manheim : John Willey and Son – VCH, 2007. 207 p.
18. Kalsi W. S., Sidhu T. S., Karthikeyan J. Evaluation of NiCoCrAlY coatings deposited on superalloy with novel cold spray process. Surface Engineering. 2014. Vol. 31, Iss. 11. pp. 840–845.
19. Rathod W. S., Khanna A. S., Karthikeyan J., Rathod R. C. Effect of N2 and the carrier gases on oxidation behavior of cold sprayed CoNiCrAlY powder to deposit bond coats. Indian I Metals. 2014. Vol. 67, Iss. 2. pp. 247–262.
20. Wong W., Irissou E., Ryabinin A. N., Legoux J. G. et al. Influence of helium and nitrogen gases on the properties of cold gas dynamic sprayed pure titanium coatings. Journal of Thermal Spray Technology. 2011. Vol. 20, Iss. 1-2. pp. 213–226.
21. Winnicki M., Maachowska A., Dudzik G., Rutkowska-Gorczyca M. et al. Numerical and experimental analysis of copper particles velocity in low-pressure cold spraying process. Surface and Coating Technology. 2015. Vol. 268. pp. 230–240.
22. Huang G., Wang H., Li X., Xing L., Xhou J. Deposition effeciency of low pressure cold sprayed aluminum coating. Materials and Manufacturing Processes. 2017. Vol. 33, Iss. 10. pp. 1100–1106.
23. Koivuluoto H., Vuoristo P. Effect of powder type and composition on structure and mechanical properties of Cu + Al₂O₃ coatings prepared by using low-pressure cold spray process. Journal of Thermal Spray Technology. 2010. pp. 1081-1092.
24. Winnicki M., Malachowska A., Piwowarczyk T., Rutkowska-Gorczyca M. et al. The bond strength of Al + Al₂O₃ cermet coatings deposited by low pressure cold spraying. Archives of Civil and Mechanical Engineering. 2016. Vol. 16. pp. 743–752.
25. Winnicki M., Maachowska A., Rutkowska-Gorczyca M., Sokoowski P. et al. Characterization of cermet coatings deposited by low-pressure cold spraying. Surface & Coatings Technology. 2015. Vol. 268. pp. 108–114.
26. Maachowska A., Winnicki M., Konat ., Piwowarczyk T. et al. Possibility of spraying of copper coatings on polyamide 6 with low pressure cold spray method. Surface and Coatings Technology. 2017. Vol. 318. pp. 82–89.
27. Kumar S, Bae G, Lee C. Deposition characteristics of copper particles on roughened substrates through kinetic spraying. Applied Surface Science. 2009. Vol. 255. pp. 3472–3479.
28. Singh R., Rauwald K. H., Mauler G., Schruefer S. et al. Effects of subtrate roughness and spray-angle on deposition behavior of coldsprayed Inconel 718. Surface and Coatings Technology. 2017. Vol. 319. pp. 249–259.
29. Klinlov S. V. Measurements of cold spray deposition efficency. Journal of Thermal Spray Technology. 2006. Vol. 15, Iss. 3. pp. 364–371.