REGULARITIES OF FORMATION AND THICKNESS CONTROL OF ALUMINUM COATINGS DURING COLD GAS-DYNAMIC SPRAYING

Oleksandr Shorinov, Dmytro Bilan

Abstract


The subject matter of this article is the regularities of the influence of cold gas-dynamic spraying (CGDS) parameters on the coating formation process. The goal of the study is to establish the relationships governing the effects of the main technological parameters of the CGDS process on aluminum coating thickness and to develop a predictive model for optimizing coating thickness. The tasks to be solved are: to implement a full-factorial three-factor experiment with variations in scanning speed, powder feed rate, and spray distance; to conduct metallographic analysis of the obtained coatings to determine deposited layer thickness; to develop a mathematical model (response surface) for the quantitative prediction of the coating thickness; and to investigate the complex effect of the studied parameters on the coating thickness in order to determine the region of high technological robustness (stability of the spraying process to random fluctuations of input variables). Methods. The deposition of ULT 02565 aluminum powder was performed using the DIMET-405 CGDS equipment. Microstructure examination and coating thickness measurements were conducted using optical metallography techniques. Process optimization and modeling were carried out using response surface methodology based on a three-factor Box-Behnken experimental design, followed by statistical evaluation of the results and the model's predictive capability using analysis of variance (ANOVA). Results. Based on experimental results, it was shown that varying the spraying process parameters enables precise control of the coating thickness to 0.2-0.83 mm per pass. An empirical model was developed that, with high accuracy, explains 96.7% of the total variance in layer thickness (root mean square error of prediction is 0.0598 mm). The analysis of variance demonstrated the statistical significance of the linear effects of scanning speed and powder feed rate, as well as the quadratic effect of spray distance. The scientific novelty of the obtained results lies in expanding the understanding of the kinetics of gas-dynamic spraying processes: for the first time, the complex effect of scanning speed and powder mass feed rate on coating thickness has been quantified. Conclusions. The results identified a region of high technological robustness in the CGDS process, located in the factor space near its geometric center (scanning speed of 30 mm/s, powder feed rate of 0.5 g/s, and spray distance of 15 mm). The developed recommendations ensure the stable formation of an aluminum coating with a predicted thickness of approximately

Keywords


coatings, microstructure, metallography, surface layer, surface treatment, spraying technology, modeling.

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DOI: 10.1007/s11666-025-01970-0




DOI: https://doi.org/10.32620/aktt.2026.4.06