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Oxidation Behavior of NBD 200 Silicon Nitride Ceramics
Author(s) -
Mukundhan Priya,
Wu Jianqing,
Du Henry H.
Publication year - 1999
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.1151-2916.1999.tb02074.x
Subject(s) - sintering , activation energy , ceramic , silicon nitride , diffusion , oxide , oxygen , materials science , oxidation process , sodium , nitride , grain boundary diffusion coefficient , grain boundary , inorganic chemistry , mineralogy , metallurgy , chemistry , chemical engineering , analytical chemistry (journal) , silicon , microstructure , nanotechnology , layer (electronics) , thermodynamics , physics , organic chemistry , engineering , chromatography
The oxidation behavior of NBD 200 Si 3 N 4 containing 1 wt% MgO sintering aid was investigated in oxygen at 900°‐1300°C. The oxide growth followed a parabolic rate law with an apparent activation energy of 260 kJ/mol. The oxide layers were enriched with sodium and magnesium because of outward diffusion of intergranular Na + and Mg 2+ cations in the ceramics. The 2‐4 orders of magnitude higher oxidation rate for NBD 200 Si 3 N 4 than for other Si 3 N 4 ceramics with a similar amount of MgO could be attributed to the presence of sodium. The oxidation process was most likely rate limited by grain‐boundary diffusion of Mg 2+ .