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Effect of Sintering Atmosphere on Densification of MgO‐Doped Al 2 O 3
Author(s) -
Paek Y.K.,
Eun K.Y.,
Kang S.J.L.
Publication year - 1988
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1988.tb06398.x
Subject(s) - sintering , materials science , atmosphere (unit) , reducing atmosphere , relative density , oxygen , metallurgy , doping , grain size , mineralogy , chemistry , thermodynamics , optoelectronics , physics , organic chemistry
The densification behavior of Al 2 O 3 ‐MgO (0.1 wt%) has been studied in O 2 and N 2 atmospheres. Powder compacts have been sintered at 1600°C for 0.5 to 8 h. For some specimens the sintering atmosphere has been changed after 30 min of sintering. Irrespective of sintering atmosphere, sintered densities are approximately the same up to 99% relative density, implying that the capillary pressure effect dominates the atmosphere effect for most of the densification stage. During extended sintering treatment the density of specimens sintered in O 2 becomes higher than that in N 2 . When the sintering atmosphere is changed from O 2 to N 2 , enhanced densification results, and vice versa. Such an effect of sintering atmosphere is explained by the diffusiveness of gases entrapped in pores, as well as by oxygen potential differences inside and outside of the specimen. Differences in grain growth rate in various atmospheres are discussed on the basis of different densification rates.