In Situ Electrochemical Atomic Force Microscopy and Auger Electro Spectroscopy Study on the Passive Film Structure of 2024‐T3 Aluminum Alloy Combined with a Density Functional Theory Calculation. Issue 12 (10th September 2019)

• Record Type: Journal Article
• Authors: Li, Ni; Dong, Chaofang; Man, Chen; Yao, Jizheng
• Is Part Of: Advanced engineering materials. Volume 21:Issue 12(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-10
• Subjects: Auger electro spectroscopy -- density functional theory calculations -- electrochemical atomic force microscopy -- passive films; Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.201900386
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : The initial growth of the passive films on the Al2 CuMg particle and Al matrix in AA2024‐T3 are investigated by in situ electrochemical atomic force microscopy (ECAFM) and ex situ characterization techniques in citric acid. The passive films are mainly composed of Al2 O3 (34%), Al(OH)3 (8.4%), AlOOH (27.2%), CuO (19.4%), and Cu2 O (11%). ECAFM images display that the film on the Al2 CuMg particle is flawed and loose. Auger electro spectroscopy (AES) results show that the thickness of the passive film on the Al2 CuMg particle is 1.4 nm, which is thinner than that on the Al matrix (2.4 nm). The combined ECAFM and AES results demonstrate that the corrosion resistance of the passive film on the Al2 CuMg is weaker than that on the Al matrix. According to the density functional theory (DFT) calculations, the average charge transfer and adsorption energy of the adsorbates (O2− /OH − /H2 O) on the Al surfaces are larger than that on the Al2 CuMg surfaces, meaning that O2 and H2 O preferably dissociate and adsorb on the Al surfaces. Moreover, the electronic interactions between the adsorbates and Al surfaces are stronger. This is the reason that the growth rate of the passive film on the Al2 CuMg particle is slower at initial stages. Abstract : The morphology and thickness of the passive film on Al2 CuMg are flawed and thinner than that on Al matrix indicating that the corrosion resistance of the passive film on Al2 CuMg is weaker. The charge transfer and adsorption energy of the adsorbates on Al surfaces are larger meaning that the O2 and H2 O preferably adsorb on the Al surfaces.