Microstructure inhomogeneity of the constituent particles of 7075-T6 aluminum alloy after alkaline cleaning and desmutting
Journal
Corrosion Science
Journal Volume
184
Date Issued
2021
Author(s)
Abstract
The microstructural evolution of AA7075-T6 aluminum alloy during alkaline cleaning in NaOH solution and desmutting in HNO3 solution was studied. AA7075-T6 contained micro-sized Mg-Si and Al-Fe-Cu constituent particles. After desmutting, Mg-Si particles transformed to Si-O particles, leaving gaps with the aluminum matrix. The aluminum matrix nearby Al-Fe-Cu particles suffered slight trenching corrosion; meanwhile, the corrosion of Al-Fe-Cu particles varied from slight corrosion, dealloying, and nano-scale galvanic corrosion induced by re-deposited Cu particulates. After alkaline cleaning and desmutting, the microstructure of constituent particles was inhomogeneous although a uniform, 5 ? 15-nm-thick Al oxide/hydroxide film covered the aluminum matrix. ? 2021 Elsevier Ltd
Subjects
Aluminum alloys; Aluminum coatings; Aluminum corrosion; Aluminum oxide; Cleaning; Copper corrosion; Galvanic corrosion; Iron alloys; Microstructure; Nanotechnology; Sodium hydroxide; Ternary alloys; 7075-T6 aluminium alloys; A aluminum; Alkaline cleaning; Aluminium matrix; B AES; B TEM; C acidic corrosion; C alkaline corrosion; C de-alloying; Inhomogeneities; Dealloying
Type
journal article