Oxidation experiments were carried out on six different aluminum alloy compositions in order to determine the effects that silicon, strontium, and magnesium have on the oxidation behavior at temperatures between 700 and 800°C. This was determined through weight gain studies using a thermogravimetric balance, microscopic examination of sample surfaces and cross-sections, and chemical analysis of the phases formed during oxidation. / The addition of 12% silicon to aluminum promoted the formation of alpha-alumina nodules on the sample surface at 800°C by reducing the viscosity of the molten metal to allow for better feeding of fresh metal through cracks in the top oxide. Strontium was found to prevent the formation of oxide nodules in an Al-12%Si alloy through the formation of a strontium containing oxide. Similarly, in a commercial 356 alloy, strontium greatly reduced the extent of oxidation by preventing the preferential oxidation of magnesium. It is believed that the mechanism responsible for this is also through the formation of a strontium containing oxide. / Oxidation experiments conducted on an Al-3%Mg alloy revealed that magnesium preferentially oxidizes to form two oxides, firstly MgO, and secondly MgAl 2O4, which forms only from the reaction of MgO and aluminum. Weight gains for this alloy were greatly affected by the oxidizing temperature. Higher temperatures shortened the incubation time to breakaway oxidation and decreased the time required to oxidize all the magnesium from the alloy.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.29856 |
| Date | January 1999 |
| Creators | Dennis, Keith. |
| Contributors | Drew, R. A. L. (advisor), Gruzleski, J. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Mining and Metallurgical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001687380, proquestno: MQ55020, Theses scanned by UMI/ProQuest. |
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