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The objective of the present work is to study the preparation of a fully dense MgO+C dopped alumina. The sintered material was characterized by their microstructure and the microstructure variation during the different thermal treatment. The atmosphere is suggested to play an important role during the annealing of MgO+C dopped A1203. From the results it can be seen that MgO+C increased the densification rate of A1203 and the density gets very close to the theoretical density. The vacuum secondary and the absence of gas in the pores have contributed to the densification rate. The other role of MgO+C in powder is to lower the boundary mobility which helps to keep the pores attached to the moving boundary even though the pores are controlling grain growth and not to change the grain size/density significantly. That is to say, the presence of carbon or MgO in powder is to inhibit grain growth and to promote the development of more uniform grain structure by formation the precipitate and segregation. Because of the above roles of MgO+C in A1203, it is possible to attain the theoretical density without the abnormal grain.