Akademik Veri Yönetim Sistemi
SURFACE AND COATINGS TECHNOLOGY, cilt.501, ss.5-15, 2025 (SCI-Expanded)
This study investigates the impact of coating composition and thickness on the electrochemical corrosion behavior of coated 7075 aluminum alloy (AA). In this study, Cu-based MMC coatings were produced on 7075 alloy by low-pressure cold gas dynamic spray (CGDS) process using four different powder compositions, namely CA (100 % Cu-Al2O3), CNZA15 (85 % Cu-Al2O3 + 15 % Ni-Zn-Al2O3), CNZA30 (70 % Cu-Al2O3 + 30 % Ni-Zn-Al2O3) and CZA (100 % Cu-Zn-Al2O3). Tafel extrapolation results demonstrated that the coatings except for CZA exhibited more positive corrosion potentials in the noble direction compared to bare 7075 AA, however all coatings increased the corrosion rate of 7075 AA. The detailed analysis of cyclic polarization (CP) curves indicated that bare 7075 alloy was more likely to experience pitting corrosion with no evidence of repassivation behavior during reverse scan, whereas Cu-based coatings were less affected by localized corrosion owing to their self-repair capabilities. Similarly, the results of electrochemical impedance spectroscopy (EIS) test conducted at 0 V (vs OCP) showed that the uncoated 7075 AA had higher impedance value than the Cu-based coatings. However, when the EIS test was carried out at 0.1 V (vs OCP), the impedance of 7075 AA dramatically, indicative of its susceptibility to localized corrosion. Among the coatings, CA demonstrated superior performance under aggressive corrosion conditions, highlighting its potential for diverse protective applications on 7075 AA.