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Effects of Trace O 2 Levels on the Nitriding Kinetics of High‐Purity Silicon Powders
Author(s) -
Parikh Raju S.,
Lightfoot Annamarie,
Haggerty John S.,
Sheldon Brian W.
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.tb02133.x
Subject(s) - nitriding , silicon , nucleation , analytical chemistry (journal) , oxygen , partial pressure , kinetics , materials science , silane , thermogravimetric analysis , metallurgy , mineralogy , chemistry , environmental chemistry , layer (electronics) , composite material , physics , organic chemistry , quantum mechanics
The effects of trace O 2 levels on the nitridation of compacts made from silane‐derived Si powders were studied in N 2 atmospheres, with oxygen levels of either 5 ppm or 10 ppb (approximately). The nitriding kinetics were studied by thermogravimetric analysis as a function of temperature (1100–1200°C) and heating rate (5°C/min and 100°C/min). Reducing the O 2 level in the nitriding gas enhanced conversion to Si 3 N 4 at lower temperatures, reduced the composition variations within the samples, and decreased the α/β ratios. The results suggest that nucleation and rapid growth of Si 3 N 4 at relatively low temperatures are possible only when the oxygen partial pressure in the system is below the threshold value for passive oxidation.