In this work, the carbothermal reduction of Al$ sb2$O$ sb3$ to AlN was studied. Several kinds of aluminum oxides including $ alpha$-Al$ sb2$O$ sb3$, $ gamma$-Al$ sb2$O$ sb3$, $ theta$-Al$ sb2$O$ sb3$ and boehmite (AlOOH) were examined in order to observe the differences in reaction behaviour and powder characteristics obtained from each type of precursor. Cane sugar (sucrose) and carbon black were used as carbon sources. Reaction conditions studied were carbon to alumina ratio, temperature and reaction time. Sucrose resulted in a close-to-stoichiometric ratio of Al$ sb2$O$ sb3$:C (1:3.2) achieving full conversion to AlN and produced a regular powder morphology, whilst carbon black required higher ratio ($>$1:4) to reach full conversion with agglomeration of the AlN powder. The optimal reaction temperature was 1600$ sp circ$C with the reaction time being dependent on the Al$ sb2$O$ sb3$ source. The results of the thermodynamic study for the Al-N-O-C system suggest a solid-state reaction process which is consistent with the experimental observations. Moreover, flowing N$ sb2$ gas flushes out the product CO gas and thus forces the equilibrium in favour of AlN formation. Reaction mechanisms are proposed for the two forms of carbon precursor.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.60643 |
| Date | January 1991 |
| Creators | Baik, Youngmin |
| 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: 001277813, proquestno: AAIMM74477, Theses scanned by UMI/ProQuest. |
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