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Effect of Sintering Atmosphere on Isolated Pores During the Liquid‐Phase Sintering of MgO‐CaMgSiO 4
Author(s) -
KIM JEONGJOO,
KIM BYUNGKI,
SONG BYUNGMOO,
KIM DOHYEON,
YOON DUK N.
Publication year - 1987
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.1151-2916.1987.tb04872.x
Subject(s) - sintering , materials science , porosity , diffusion , atmosphere (unit) , oxygen , liquid phase , shrinkage , phase (matter) , chemical engineering , reducing atmosphere , ceramic , oxide , metallurgy , mineralogy , composite material , chemistry , organic chemistry , physics , engineering , thermodynamics
The shrinkage behavior of isolated pores during the liquidphase sintering of MgO‐CaMgSiO 4 at 1650°C in O 2 and N 2 atmospheres has been studied. When 90MgO‐ 10Ca MgSiO 4 specimens containing artificially produced large spherical pores are sintered in O 2 , the liquid and grains flow into the pores as oxygen diffuses out. When sintered in N 2 the pores remain intact even after a long time, because the N 2 gas entrapped in them does not diffuse out. The effect of the sintering atmosphere has also been studied in a fine powder mixture of 80MgO 20CaMgSiO 4 composition. Changing the atmosphere from O 2 to N 2 during the sintering treatment reduces the porosity, probably because of the enhanced oxygen diffusion from the pores. The pores grow when the sintering atmosphere is changed from N 2 to O 2 , probably because of oxygen diffusion into the pores from the specimen surface. The practical implication of these results is that changing the atmosphere from O 2 to air during the liquid‐phase sintering of oxide ceramics can greatly reduce the porosity.