Date of Award
8-1-2019
Thesis Type
masters
Document Type
Thesis (Restricted Access)
Divisions
eng
Department
Faculty of Engineering
Institution
Universiti Malaya
Abstract
The effect of manganese as a densification enhancing additive in alumina was studied. Various manganese percentages (0.1, 0.5, and 1.0 wt. %) were added to alumina powder. The mixture was homogenized using wet milling process. Sintering was carried out in conventional furnace and in hybrid multimode microwave furnace. XRD analysis revealed the precipitation of a spinel second phase (MnAl2O4) in manganese-doped samples as a result of manganese limited solubility in the corundum lattice. 0.1 wt. % manganese addition significantly enhanced the densification process, hindered grain growth, and improved hardness of alumina sintered at 1500 °C. At 1500 °C, 97.5 % relative density was obtained for alumina with 0.1 wt. % manganese content, whereas undoped alumina could only achieve 94.2 % relative density. 0.5 and 1.0 wt. % manganese concentrations resulted in abnormal grain growth at high sintering temperature (1600 °C). The study also revealed that microwave sintering was effective in suppressing grain growth of alumina. In addition, the hardness was dependent on the sintered bulk density and that grain coarsening ensued as the density of the sintered alumina exceeded 95% of theoretical.
Note
Dissertation (M.A.) – Faculty of Engineering, Universiti Malaya, 2019.
Recommended Citation
Salem Omar Abdullah, Dhuban, "Microwave and conventional sintering of manganese-doped alumina: Densification and mechanical Properties / Salem Dhuban" (2019). Student Works (2010-2019). 6577.
https://knova.um.edu.my/student_works_2010s/6577