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The phase diagram of the MnO-Al 2 O 3 system.

The phase diagram of the MnO-Al 2 O 3 system.

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Effect of manganese oxide and titanium oxide as additives on sintering of alumina is described. Sintered density, average grain size and microstructural features have been investigated along with the mechanical properties. The addition of manganese oxide produced a relatively uniform, dense microstructure at high temperature. Titania up to 0.2 wt.%...

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... to the phase diagram given in Fig. 3, a eutectic composition is present on the MnO-rich side of the binary MnO-Al 2 O 3 system at 1520 C [17]. The micrographs shown for the samples with 0.1-0.5 wt.% manganese oxide addition sintered at 1550-1600 C do not indicate the presence of any secondary phase formation between the grains. Based on these observations it is concluded ...

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... In our air-sintered samples containing MnO, the porosity was less than 0.3%, and this was achieved without expensive sintering equipment. In a previous study [74], the addition of manganese oxide to aluminum oxide resulted in an increase in grain growth. High hardness values were observed with the addition of manganese oxide (23.20 GPa) compared to unalloyed aluminum oxide (18.13 GPa). ...
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... The relatively lower calcination temperature was favored due to its role in the assemblage of the nearly pure phase. In addition, the lower calcination temperature enhanced the thermal stability by avoiding the decomposition of Al 2 TiO 5 into Al 2 O 3 and TiO 2 that occurs at high calcination temperatures [30,31]. ...
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... The presence of these oxides in solid solution or as nano inclusions can significantly affect the sintering process, densification rate, and activation energy. In addition, the presence of sintering aids modifies the microstructure of the final ceramic because of effects such as Zener pinning or solute-drag [5][6][7][8][9][10][11][12][13][14]. These factors combine to facilitate the production of high-grade dense alumina with improved properties. ...