| Title |
Localised Corrosion of UNS A94045 in an Acidified Chloride Solution |
| Authors |
이준섭(Jun-Seob Lee) ; 이여경(Yeokyeong Lee) ; 공경호(Kyeong-Ho Kong) ; 김봉윤(Bong-Yoon Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2026.64.7.597 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
UNS A94045; Localised corrosion; Immersion; Chloride ion |
| Abstract |
Time-dependent localised corrosion behaviour of UNS A94045 was investigated in an acidified chloride environment. Immersion tests were performed in a Sea Water Acetic Acid Test (SWAAT) solution (1.0 wt.% CH3COOH and 4.2 wt.% NaCl) for 0, 24, 48, 72, and 169 h. The alloy microstructure consisted of primary a-Al dendrites and interdendritic eutectic (a-Al+Si) regions. Localised corrosion initiated in the interdendritic eutectic regions during the early stage, while localised corrosion in the primary a-Al regions remained limited within the examined exposure periods. Three-dimensional surface profile analysis was conducted, and the maximum depth, the average depth, and the maximum-to-average depth ratio were obtained as depth-based indices. Both the maximum and average depths increased with immersion time, whereas the depth ratio increased markedly, indicating that the depth development became increasingly non-uniform and was dominated by specific locations at longer exposure rather than by uniform surface degradation. Scanning Kelvin probe force microscopy (SKPFM) measurements showed higher contact potential difference (CPD) values for eutectic Si than for the a-Al phases, indicating a microstructural potential difference within the eutectic region. On the basis of the immersion and the CPD difference, localised corrosion was considered to initiate in eutectic a-Al adjacent to eutectic Si. These results provide experimental evidence for time-dependent damage evolution and clarify microstructural susceptibility of Al-Si alloys under acidified chloride conditions. |