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The purpose of this investigation is to understand the structure of trapped intermetallics particles and localized composition changes in the anodized anodic oxide film on AA1050 aluminium substrates.

The morphology and composition of Fe‐containing intermetallic particles incorporated into the anodic oxide films on industrially pure aluminium (AA1050, 99.5 per cent) has been investigated. AA1050 aluminium was anodized in a 100 ml/l sulphuric acid bath with an applied voltage of 14 V at 20°C ±2°C for 10 or 120 min. The anodic film subsequently was analyzed using focused ion beam‐scanning electron microscopy (FIB‐SEM), SEM, and EDX.

The intermetallic particles in the substrate material consisted of Fe or both Fe and Si with two different structures: irregular and round shaped. FIB‐SEM cross‐sectioned images revealed that the irregular‐shaped particles were embedded in the anodic oxide film as a thin strip structure and located near the top surface of the film, whereas the round‐shaped particles were trapped in the film with a spherical structure, but partially dissolved and were located throughout the thickness of the anodic film. The Fe/Si ratio of the intermetallic particles decreased after anodizing.

This paper shows that dual beam FIB‐SEM seems to be an easy, less time consuming and useful method to characterize the cross‐sectioned intermetallic particles incorporated in anodic film on aluminium.

The purpose of this paper is to understand the effect of pressurized steam on surface changes, structures of intermetallic particles and corrosion behavior of AA1050 aluminium.

Industrially pure aluminium (AA1050, 99.5 per cent) surfaces were exposed to pressurized steam produced from a commercial pressure cooker at the maximum temperature of 116oC for 10 min. Surface morphology was observed using SEM‐EDX and FIB‐SEM. Phase identification and compositional depth profiling were investigated using XRD and GDOES, respectively. Potentiodynamic polarization measurements were used to study corrosion behavior.

A 590 nm boehmite oxide layer was generated on AA1050 associated with partially dissolved and/or fallen off Fe‐containing intermetallic particles after exposure to pressurized steam. A significant reduction (25 times) in anodic and cathodic reactivities was observed due to the formation of the compact oxide layer.

This paper reveals a detailed investigation of how pressurized steam can affect the corrosion behaviour of AA1050 aluminium and the structure of Fe‐containing intermetallic particles.