INFLUENCE OF ELECTROPHORETIC DEPOSITION ROUTES ON STRUCTURAL EVOLUTION AND ELECTRICAL BEHAVIOR OF ZNO COATING DEPOSITED ON WAAM INCONEL 625

Öz

Wire Arc Additive Manufacturing (WAAM) surfaces exhibit heterogeneous microstructures and oxide layers which might influence coating deposition and interfacial properties. The influence of electrophoretic deposition chemistry on coating structure, coating architecture, and electrical properties of WAAM-fabricated nickel-based superalloys still lacks sufficient understanding. In this study, conventional electrophoretic deposition (EPD) and sol-gel derived electrophoretic deposition techniques were employed for ZnO coating deposition on WAAM-fabricated Inconel 625 superalloys. ZnO coatings were deposited at 10 V for 1 min and then subjected to heat treatment at 600°C for 1 h. The structural and morphological properties of ZnO coatings were studied using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy while the electrical properties were studied using a Wheatstone bridge circuit. The crystalline nature of ZnO coatings was observed for both conventional and sol-gel derived EPD routes; however, differences in coating structure and compactness were observed. Conventional EPD route exhibited a coating porosity of 14.2 ± 1.5% and coating thickness of 1.4 ± 0.2 µm while sol-gel derived EPD route exhibited a coating porosity of 3.8 ± 0.6% and coating thickness of 0.92 ± 0.18 µm. The Zn/(Ni + Cr) ratio was observed to increase from 0.62 to 3.23, indicating better coating coverage for sol-gel derived EPD route coatings. The conductivity of Inconel 625 was observed to reduce by 10.5% for conventional electrophoretic deposition route coatings and 7.2% for sol-gel electrophoretic deposition route coatings. The suspension chemistry was observed to influence coating compactness, coating structure and interfacial electrical properties of WAAM-fabricated Inconel 625 superalloys. Sol-gel derived EPD route coatings exhibited better homogeneity and electrical stability for ZnO coatings.

Anahtar Kelimeler

• WAAM
• Inconel 625
• ZnO coating
• Electrophoretic deposition
• Electrical conductivity.

Kaynakça

1. 1. Kishor, G., Mugada, K.K., Mahto, R.P., “Wire arc additive manufacturing of titanium alloys for enhancing mechanical properties and grain-refinement”, Metals and Materials International, Vol. 32, Issue 1, Pages 50-80, 2026.
2. 2.Bhuvanesh Kumar, M., Sathiya, P., Senthil, S.M., “A critical review of wire arc additive manufacturing of nickel-based alloys: principles, process parameters, microstructure, mechanical properties, heat treatment effects, and defects”, Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol. 45, Issue 3, Pages 164, 2023.
3. 3.Iqbal, H., Ascari, A., Fortunato, A., Liverani, E., “Elucidating the effects of metal transfer modes and investigating the material properties in wire-arc additive manufacturing (WAAM)”, Progress in Additive Manufacturing, Vol. 10, Issue 5, Pages 3335-3360, 2025.
4. 4.Saeed, M., Marwani, H.M., Shahzad, U., Asiri, A.M., Rahman, M.M., “Recent advances, challenges, and future perspectives of ZnO nanostructure materials towards energy applications”, The Chemical Record, Vol. 24, Issue 1, Pages e202300106, 2024.
5. 5.Zhan, F., Wen, G., Li, R., Feng, C., Liu, Y., Liu, Y., La, P., “A comprehensive review of oxygen vacancy modified photocatalysts: synthesis, characterization, and applications”, Physical Chemistry Chemical Physics, Vol. 26, Issue 15, Pages 11182-11207, 2024.
6. 6.Abdullah, M.T., Sherzad Othman, M., “Analysing magnesium oxide nanostructures prepared using several methods: a review”, Physica Scripta, Vol. 100, Issue 12, Pages 122001, 2025.
7. 7.Chakrabarti, B.K., Gençten, M., Bree, G., Dao, A.H., Mandler, D., Low, C.T.J., “Modern practices in electrophoretic deposition to manufacture energy storage electrodes”, International Journal of Energy Research, Vol. 46, Issue 10, Pages 13205-13250, 2022.
8. 8.Wang, Y., Yang, Y., Liu, M., “Electrophoretic deposition of halloysite nanotubes/PVA composite coatings for corrosion protection of metals”, Applied Materials Today, Vol. 29, Pages 101657, 2022.

9. 9.Kou, Q., Ge, C., Sun, L., Qi, W., Xu, J., Zhang, J., Ye, H., “Preparation of TiB2 coatings on graphite via electrophoretic deposition in NaCl-KCl-AlF3 molten salts”, Journal of The Electrochemical Society, Vol. 172, Issue 1, Pages 012503, 2025.
10. 10.Sikkema, R., Zhang, C., Zhitomirsky, I., “New developments in synthesis of bioceramics, electrophoretic deposition of biopolymer, and composites using organic bases”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 716, Pages 136691, 2025.
11. 11.Azzouz, I., Khlifi, K., Faure, J., Dhiflaoui, H., Larbi, A.B.C., Benhayoune, H., “Mechanical behavior and corrosion resistance of sol-gel derived 45S5 bioactive glass coating on Ti6Al4V synthesized by electrophoretic deposition”, Journal of the Mechanical Behavior of Biomedical Materials, Vol. 134, Pages 105352, 2022.
12. 12.Yu, Y., Matsunaga, M., “Sol–Gel Electrophoretically Deposited TiO2–Multiwalled Carbon Nanotube–SiO2 Thin-Film Electrode with High Photoelectrochemical Activity”, ACS Omega, Vol. 10, Issue 8, Pages 7857-7875, 2025.
13. 13.Sharma, G., Rathore, S., Kumar, H., Yadav, K.K., “Wear Properties of Wire and Arc Additive Manufacturing Components: A review on recent developments on Processes, Materials and Parameters”, Library of Progress-Library Science, Information Technology & Computer, Vol. 44, Issue 3, 2024.
14. 14.Hashish, M., “Abrasive waterjet machining”, Materials, Vol. 17, Issue 13, Pages 3273, 2024.
15. 15.Verde, M., Peiteado, M., Caballero, A.C., Villegas, M., Ferrari, B., “Electrophoretic deposition of transparent ZnO thin films from highly stabilized colloidal suspensions”, Journal of Colloid and Interface Science, Vol. 373, Issue 1, Pages 27-33, 2012.
16. 16.Han, Y., Hwang, G., Kim, D., Bradford, S.A., Lee, B., Eom, I., Kim, H., “Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating”, Water Research, Vol. 90, Pages 247-257, 2016.
17. 17.Chang, C., Rad, S., Gan, L., Li, Z., Dai, J., Shahab, A., “Review of the sol–gel method in preparing nano TiO2 for advanced oxidation process”, Nanotechnology Reviews, Vol. 12, Issue 1, Pages 20230150, 2023.
18. 18.Zhao, J., Liu, W., Azari, R., Chen, L., Wang, K., Boccaccini, A.R., Sun, X.W., “Electrophoretic deposition”, Nature Reviews Methods Primers, Vol. 6, Issue 1, Pages 12, 2026.
19. 19.Feng, J., Zhang, X., Chu, Y., Wan, J., “Hydrogen embrittlement of Ni-based superalloy inconel 625 fabricated by wire arc additive manufacturing: the role of laves phase”, Metals and Materials International, Vol 30, Issue 4, Pages 872-885, 2024.
20. 20.Nandi, S., Manivannan, R., Dubey, P., Bhagyaraj, J., Chowdhury, S.G., Rajinikanth, V., “Role of inter-pass temperature on cooling rate, segregation and mechanical properties of wire arc additively manufactured Inconel 625”, Materials Characterization, Pages 115869, 2025.
21. 21.Zhang, P.Z., Tang, B., “Mechanism of high temperature oxidation of Inconel 625 superalloy with various solution and ageing heat treatment processes”, Transactions of Nonferrous Metals Society of China, Vol. 34, Issue 11, Pages 3662-3676, 2024.
22. 22.Hur, J., Choi, Y.M., Kim, T., Yi, S.H., Li, L., Chun, S.E., “Effect of applied potential polarity on electrochemical properties of electrophoretically deposited activated carbon on an indium tin oxide substrate”, Surfaces and Interfaces, Vol. 37, Pages 102660, 2023.
23. 23.Parthasarathy, S., Madhuri, A., Swain, B.P., “Adhesion and Surface Modification of Coating Materials”, Advances in Mechanical Coating: Processing, Properties and Applications, Pages 109-136, Springer Nature Singapore, Singapore, 2025.
24. 24.Wei, J., Yuan, S., Yang, S., Gao, M., Fu, Y., Hu, T., Zhang, W., “Waterjet-guided laser processing of SiC/SiC ceramic matrix composites to obtain high cleanliness and low oxidation damage characteristics surfaces”, Surface and Coatings Technology, Vol. 484, Pages 130791, 2024.
25. 25.Mohammada, A., Al-Jafa, H.A., Ahmeda, H.S., Mohammedb, M., Khodairc, Z., “Structural and morphological studies of ZnO nanostructures”, Journal of Ovonic Research, Vol. 18, Issue 3, Pages 443-452, 2022.
26. 26.Mahendiran, S., Ramanujam, R., “Investigation of surface residual stress, mechanical properties, and metallurgical characterization of Inconel 625 multilayer thin-wall component using cold metal transfer technique”, Journal of Materials Engineering and Performance, Vol. 34, Issue 2, Pages 1026-1049, 2025.
27. 27.Madesh, R., Kumar, K.G., “Development of metallurgical and mechanical properties of nickel-based superalloy employed by wire arc additive manufacturing technique”, Journal of Materials Engineering and Performance, Vol. 33, Issue 13, Pages 6718-6737, 2024.
28. 28.Kumar, A., Jaiswal, J., Tsuchiya, K., Mulik, R.S., “Modern coating processes and technologies”, Coating Materials: Computational Aspects, Applications and Challenges, Pages 33-80, Springer Nature Singapore, Singapore, 2023.
29. 29.Samanta, P.K., “Effect of microstrain on the crystallite size of ZnO nanoparticles: X-ray peak profile and Rietveld analysis”, Next Materials, Vol. 8, Pages 100841, 2025.
30. 30.Srilatha, N., Prasad, S.S., Sahithi, V.V.D., Hari, S.S., Balashowry, K., “Developing Hybrid and Functional Materials with Sol-gel Chemistry–A Review”, Journal of Environmental Nanotechnology, Vol. 14, Issue 3, Pages 540-558, 2025.
31. 31.Karmakar, S., Deo, M., Rahaman, I., Mohanty, S.K., “Nanoparticle Deposition Techniques for Silica Nanoparticles: Synthesis, Electrophoretic Deposition, and Optimization-A review”, arXiv preprint, arXiv:2503.22593, 2025.
32. 32.Nizar, B.M., Lajnef, M., Chaste, J., Chtourou, R., Herth, E., “Highly C-oriented (002) plane ZnO nanowires synthesis”, RSC Advances, Vol. 13, Issue 22, Pages 15077-15085, 2023.
33. 33.Bouderbala, I.Y., Guessoum, A., Rabhi, S., Bouhlassa, O., Bouras, I.E., “Optical band-diagram, Urbach energy tails associated with photoluminescence emission in defected ZnO thin films deposited by sol–gel process dip-coating: effect of precursor concentration”, Applied Physics A, Vol. 130, Issue 3, Pages 205, 2024.
34. 34.Khorsand Zak, A., Hashim, A.M., “Advanced XRD peak broadening analysis of gallium-doped ZnO nanoparticles for crystallite size evaluation”, Scientific Reports, 2025.
35. 35.Koul, P., Siddaramu, Y., “A Review of Wire Arc Additive Manufacturing”, International Journal of Scientific Research in Modern Science and Technology, Vol. 4, Issue 8, Pages 01-32, 2025.
36. 36.De Riccardis, M.F., “Ceramic coatings obtained by electrophoretic deposition: fundamentals, models, post-deposition processes and applications”, Ceramic Coatings: Applications in Engineering, Pages 43-68, 2012.
37. 37.Agnihotri, P., Rani, R., Bdikin, I., Sharma, S., Rai, R., “Preparation of nano-structured barium titanate via electrophoretic deposition (EPD) and their electrical and ionic conductivity via impedance spectroscopy”, Ionics, Vol. 31, Issue 2, Pages 2259-2275, 2025.
38. 38.Tasis, D., “Recent progress on the synthesis of graphene-based nanostructures as counter electrodes in DSSCs based on iodine/iodide electrolytes”, Catalysts, Vol. 7, Issue 8, Pages 234, 2017.
39. 39.Sreekala, A.P., Nair, P.R., Kadavath, J.K., Krishnan, B., Avellaneda, D.A., Anantharaman, M.R., Shaji, S., “Laser processing in liquids: insights into nanocolloid generation and thin film integration for energy, photonic, and sensing applications”, Beilstein Journal of Nanotechnology, Vol. 16, Issue 1, Pages 1428-1498, 2025.
40. 40.Karrari, S., Mohammadzadeh, H., Jafari, R., “Effect of coating parameters on the properties of the Zn–Cu–Ni oxide nanocomposite coating deposited on stainless steel 316LC by EPD”, Reaction Chemistry & Engineering, Vol. 10, Issue 11, Pages 2571-2587, 2025.
41. 41.Arun, A.P., Sreenivasan, N., Patil, J.H., Kusanur, R., Ramachandraiah, H.L., Ramakrishna, M., “Thin Films for Next Generation Technologies: A Comprehensive Review of Fundamentals, Growth, Deposition Strategies, Applications, and Emerging Frontiers”, Processes, Vol. 13, Issue 12, Pages 3846, 2025.
42. 42.Hofmann, J., Teutenberg, D., Meschut, G., “Method development for the mechanical characterisation of cathodic electrodeposition coatings for numerical simulation of bonded joints”, The Journal of Adhesion, Pages 1-16, 2026.
43. 43.Kaschnitz, E., Kaschnitz, L., Heugenhauser, S., “Electrical resistivity measured by millisecond pulse heating in comparison with thermal conductivity of the superalloy Inconel 625 at elevated temperature”, International Journal of Thermophysics, Vol. 40, Issue 3, Pages 27, 2019.
44. 44.Tun, H.M., Wulansari, R.E., Pradhan, D., Naing, Z.M., “Design, fabrication and measurement of metal-semiconductor field effect transistor based on zinc oxide material”, Journal of Engineering Researcher and Lecturer, Vol. 2, Issue 3, Pages 104-111, 2023.
45. 45.Jadhav, S., Kusekar, S., Belure, A., Digole, S., Mali, A., Cheepu, M., Kim, D., “Recent progress and scientific challenges in wire-arc additive manufacturing of metallic multi-material structures”, Journal of Manufacturing and Materials Processing, Vol. 9, Issue 8, Pages 284, 2025.
46. 46.Gartner, M., Stroescu, H., Mitrea, D., Nicolescu, M., “Various applications of ZnO thin films obtained by chemical routes in the last decade”, Molecules, Vol. 28, Issue 12, Pages 4674, 2023.
47. 47.Shah, V., Choudhury, A., Thakrar, Y., Patil, T., Dharaskar, S., “Functionalized Nanomaterial–Based Thin‐Film Transistors and Display Devices”, Functionalized Nanomaterials for Electronic and Optoelectronic Devices: Design, Fabrications and Applications, Pages 195-234, 2025.
48. 48.Nunes, V.F., Júnior, P.H.F.M., Almeida, A.F.L., Freire, F.N.A., “EPD method for thin films on solar cells”, Materials Letters, Vol. 358, Pages 135896, 2024.
49. 49.Khudiar, S.S., Nayef, U.M., Mutlak, F.A.H., Abdulridha, S.K., “Characterization of NO2 gas sensing for ZnO nanostructure grown hydrothermally on porous silicon”, Optik, Vol. 249, Pages 168300, 2022.