Preparation of composite powder based on nano-TiO2 and Cr2O3 using a spray dryer, for atmospheric plasma spraying, designed for HPAL systems
- PlasmaScience LLP, Ust-Kamenogorsk 070000, Kazakhstan
- Sakarya University, Thermal Spray Research and Application Laboratory, Sakarya 54050, Turkey
Received: 2025-05-03
Revised: 2025-06-12
Accepted: 2025-06-21
Published in Issue 2025-06-30
Copyright (c) 2025 Bauyrzhan Rakhadilov, Zhangabay Turar, Dauir Kakimzhanov, Aidar Kengesbekov (Author)

This work is licensed under a Creative Commons Attribution 4.0 International License.
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1.
Rakhadilov B, Turar Z, Kakimzhanov D, Kengesbekov A. Preparation of composite powder based on nano-TiO2 and Cr2O3 using a spray dryer, for atmospheric plasma spraying, designed for HPAL systems. J Theor Appl phys. 2025 Jun. 30;19(3). Available from: http://oiccpress.com/jtap/article/view/17271
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Abstract
In this study, composite coatings based on TiO₂ and TiO₂–Cr₂O₃ nanopowders were fabricated by air plasma spraying for High-Pressure Acid Leaching (HPAL) systems. Nanopowders were agglomerated in aqueous medium using polyvinyl alcohol and spray-dried into spherical granules. Coatings were deposited onto 12Kh18N10T stainless steel substrates. X-ray diffraction (XRD) analysis revealed rutile TiO₂ and Cr₂O₃ as the main crystalline phases, with minor Ti₂O₃. For TiO₂-only coatings, the XRD pattern showed predominantly rutile (R-TiO₂) and a small amount of anatase (A-TiO₂); brookite was absent. Rutile formation is attributed to high plasma spraying temperatures that promote anatase-to-rutile transformation. The coatings had dense microstructures with low porosity due to optimized powder preparation and spraying. Microhardness of TiO₂–Cr₂O₃ coatings reached 1015 HV, 40% higher than pure TiO₂ (723 HV). Tribological tests under a 3 N load and 500 m sliding distance showed a reduced friction coefficient from 0.98 to 0.65. The wear rate of TiO₂–Cr₂O₃ coatings was 4.2 × 10⁻⁵ mm³/N·m, indicating enhanced wear resistance. These findings demonstrate that Cr₂O₃ addition and optimized powder processing yield harder, denser, and more durable coatings, suitable for harsh service conditions.Keywords
- Coatings,
- Plasma spraying,
- Agglomeration,
- Structure,
- Wear resistance,
- Microhardness
References
- Vernhes, L., Azzi, M., Bousser, E., Schmitt, T., Lamarre, J.M., Klemberg-Sapieha, J.E.: Hybrid Co-Cr/W-WC and Ni-W-Cr-B/W-WC Coating Systems. J Therm Spray Tech. 25, 346–356 (2016). https://doi.org/10.1007/s11666-015-0357-5
- Vernhes, L., Bekins, C., Lourdel, N., Poirier, D., Lima, R.S., Li, D., Klemberg-Sapieha, J.E.: Nanostructured and Conventional Cr2O3, TiO2, and TiO2-Cr2O3 Thermal-Sprayed Coatings for Metal-Seated Ball Valve Applications in Hydrometallurgy. J Therm Spray Tech. 25, 1068–1078 (2016). https://doi.org/10.1007/s11666-016-0405-9
- Vernhes, L.: Thin Coatings for Heavy Industry: Advanced Coatings for Pipes and Valves.
- Pearson, M., Cheuk, F., Sist, C.: An Entropy Approach to Optimizing Heat Recovery in High-Pressure Autoclave Circuits. In: Proceedings of the 62nd Conference of Metallurgists, COM 2023. pp. 79–97. Springer Nature Switzerland, Cham (2023)
- Vaughan, J., Reid, P., Alfantazi, A.: Corrosion of Ti-2 and Ti-7 relevant to nickel acid leach chemistry. Hydrometallurgy. 101, 156–165 (2010). https://doi.org/10.1016/j.hydromet.2009.12.011
- Kim, G.E., Brzezinski, T.A., Leblanc, L., & Kharlanova, E. Thermal spray coatings for ball valves used in Nickel/Cobalt pressure acid leaching. In International Thermal Spray Conference. – ASM International 2000, 83607, 1149-1153.
- Vernhes, L., Bekins, C., Lourdel, N., Poirier, D., Lima, R.S., Li, D., Sapieha, J.-E.: Nanostructured and conventional Cr₂O₃, TiO₂, and TiO₂-Cr₂O₃ thermal-sprayed coatings for metal-seated ball valve applications in hydrometallurgy. Journal of Thermal Spray Technology. 25, 1068–1078 (2016). https://doi.org/10.1007/s11666-016-0405-9
- Kim, G.E., Walker, J.: Successful Application of Nanostructured Titanium Dioxide Coating for High-Pressure Acid-Leach Application. J Therm Spray Tech. 16, 34–39 (2007). https://doi.org/10.1007/s11666-006-9004-5
- Vernhes, L., Bekins, C., Lourdel, N., Poirier, D., Lima, R.S., Li, D., Sapieha, J.-E.: Nanostructured and conventional Cr₂O₃, TiO₂, and TiO₂-Cr₂O₃ thermal-sprayed coatings for metal-seated ball valve applications in hydrometallurgy. Journal of Thermal Spray Technology. 25, 1068–1078 (2016). https://doi.org/10.1007/s11666-016-0405-9
- Bastan, F.E., Erdogan, G., Moskalewicz, T., Ustel, F.: Spray drying of hydroxyapatite powders: The effect of spray drying parameters and heat treatment on the particle size and morphology. Journal of Alloys and Compounds. 724, 586–596 (2017). https://doi.org/10.1016/j.jallcom.2017.07.116
- Sagdoldina, Z., Kot, M., Baizhan, D., Buitkenov, D., Sulyubayeva, L.: Influence of Detonation Spraying Parameters on the Microstructure and Mechanical Properties of Hydroxyapatite Coatings. Materials. 17, 5390 (2024). https://doi.org/10.3390/ma17215390
- Kakimzhanov, D., Rakhadilov, B., Sulyubayeva, L., Dautbekov, M.: Influence of Pulse-Plasma Treatment Distance on Structure and Properties of Cr3C2-NiCr-Based Detonation Coatings. Coatings. 13, 1824 (2023). https://doi.org/10.3390/coatings13111824
- Budilov, V.V.; Ramazanov, K.N.; Yagafarov, I.I.; Dautov, S. K.; Yansaitova, M. I. Analiz i prognoziro-vaniye ekspluatatsionnykh povrezhdeniy pokrytiy TiN pri vozdeystvii klimaticheskikh faktorov i korrozion-no-aktivnykh sred. Novosti materialovedeniya. Nauka i tekhnika 2015, 5, 2-2. (In Russian).
- Maulet, M., Rakhadilov, B.K., Sagdoldina, Zh.B., Kassymov, A.B., Kakimzhanov, D.N.: Influence of the detonation-spraying mode on the phase composition and properties of Ni-Cr coatings. Eurasian J. Phys. Funct. Mater. 4, 249–254 (2020). https://doi.org/10.29317/ejpfm.2020040307
- Sert, Y., Toplan, N. Tribological behavior of a plasma-sprayed Al2O3-TiO2-Cr2O3 coating. Materials and technology 2013, 47(2), 181-183.
- Owen, M.W., Cooper, M.W.D., Rushton, M.J.D., Claisse, A., Lee, W.E., Middleburgh, S.C.: Diffusion in undoped and Cr-doped amorphous UO2. Journal of Nuclear Materials. 576, 154270 (2023). https://doi.org/10.1016/j.jnucmat.2023.154270
- Ingole, S., Charanpahari, A., Kakade, A., Umare, S.S., Bhatt, D.V., Menghani, J.: Tribological behavior of nano TiO2 as an additive in base oil. Wear. 301, 776–785 (2013). https://doi.org/10.1016/j.wear.2013.01.037
- Yang, H. et al. (2025). The Damage Evolution of a Cr₂O₃–TiO₂ Coating Subjected to Cyclic Impact and Corrosive Environments and the Influence of a Nickel Intermediate Layer. Coatings, 15(1), 98.
- Zhao, Y. et al. (2024). Plasma Spraying NiCoCrAlY–Cr₂O₃–AgMo Coatings: Fabrication and Tribological Mechanisms. Coatings, 14(10), 1233.
- Duda, A. et al. (2024). Preparation, Characterization, and Photocatalytic Performance of Atmospheric Plasma-Sprayed TiO₂/Al₂O₃ Coatings on Glass Substrates. Archives of Civil and Mechanical Engineering, 24, 142.
- Ru, P. et al. (2023). Effects of SiC on Microstructure and Properties of Coatings Prepared by Plasma Spraying Cr₂O₃–Al–SiC Powder. Journal of Thermal Spray Technology, 32, 1350–1361.
- Wang, Y. et al. (2023). Effect of Cr₂O₃ on the Microstructure and Wear Resistance of Coatings Prepared from Cr₂O₃–SiC–Al Composite Powders. Materials Chemistry and Physics, 127860.