Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


한국표면공학회지 (52권2호 62-71)

TEM Analysis on Oxide Films of Al1050 and Al7075 Exposed to 24-month Atmospheric Conditions

24개월 대기 노출된 Al1050 및 Al7075 알루미늄 합금 산화막에 대한 투과전자현미경 분석

Kim, Dae-Geon;Kim, Ga-Rim;Choi, Wonjun;Bahn, Chi Bum;

부산대학교 기계공학부;
School of Mechanical Engineering, Pusan National University;

DOI : 10.5695/JKISE.2019.52.2.62


Al1050 and Al7075 alloy specimens were exposed to atmospheric conditions for 24 months and analyzed by Transmission Electron Microscopy to characterize their corrosion behavior and oxide film characteristics, especially focusing on intergranular corrosion or oxidation. In general, the intergranular oxygen penetration depth of Al1050 was deeper than Al7075. Since O and Si signals were overlapped at the oxidized grain boundaries of Al1050 and Mg is not included in Al1050, it is concluded that Si segregated along the grain boundaries directly impacts on the intergranular corrosion of Al1050. Cr-Si or Mg-Si intermetallic particles were not observed along the grain boundaries of Al7050, but Mg-Si particle was barely observed in the matrix. 10-nm size Mg-Zn particles were also found all over the matrix. Mg was mainly observed along the oxidized grain boundary of Al7075, but Si was not detected due to the Mg-Si particle formation in the matrix and relatively low concentration of Si in Al7075. Therefore, it is thought that Mg plays an important role in the intergranular corrosion of Al7075 under atmospheric corrosion conditions.


Aluminum alloys;Atmospheric corrosion;Intergranular corrosion;TEM;