Calorimetric study of the oxidation of Al–Mg alloys for the prediction of healing of the double oxide film defect

• Published in: Journal of thermal analysis and calorimetry Vol. 113; no. 2; pp. 769 - 777
• Main Authors: Amirinejhad, Sajad, Raiszadeh, Ramin, Doostmohammadi, Hamid
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-08-2013; Springer
• Subjects: Air pollution; Al-Mg alloys; Aluminum alloys; Aluminum base alloys; Aluminum oxide; Aluminum |c Binary systems; Analytical Chemistry; Barometric pressure; Bifilm; Binary systems; Calorimetry; Chemical properties; Chemistry; Chemistry and Materials Science; Cross-disciplinary physics: materials science; rheology; Defects; Differential scanning calorimetry; Double oxide film defect; Exact sciences and technology; Healing; Inorganic Chemistry; Magnesium; Magnesium |c Binary systems; Materials science; Measurement Science and Instrumentation; Melts; MgAl2O4; MgO; Other topics in materials science; Oxidation; Oxidation-reduction reaction; Oxide coatings; Physical Chemistry; Physics; Polymer Sciences; Specialty metals industry; Spinel group; Thermodynamics; Differential scanning calorimetry; MgAl; MgO; Double oxide film defect; Al–Mg alloys; Healing; Bifilm; O; Scanning electron microscopy; Oxide layer; Al―Mg alloys; Magnesium alloys; Prediction; Defects; Surface structure; Characterization; Energy-dispersive X-ray spectrometry; Aluminium alloys; Morphology; Oxidation; Thermal analysis; Magnesium Oxides
• ISSN: 1388-6150; 1588-2926; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-012-2810-8

The oxidation of Al alloys containing 0.3–4.5 wt% Mg in an atmosphere with a very low oxygen partial pressure (<0.5 ppm, to depict the atmosphere within a double oxide film defect) was studied using differential scanning calorimetry and scanning electron microscopy. The results showed that a newly formed Al
2
O
3
layer held in an Al–Mg melt first transformed to MgAl
2
O
4
spinel and then to MgO. This mechanism was the same for all the Al alloys containing 0.3–4.5 wt% Mg, but the kinetics of the transformations were different and depended on the Mg content of the melt. The results also suggest that the two layers of a double oxide film defect that is held in an Al melt containing 0.3–4.5 wt% Mg can heal (i.e. bond to each other) if held in the liquid metal for a long enough period of time.