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Nitridation of Amorphous Silica with Ammonia
Author(s) -
Sjöberg Jörgen,
Pompe Robert
Publication year - 1992
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.1151-2916.1992.tb04482.x
Subject(s) - ammonia , amorphous solid , nitriding , decomposition , yield (engineering) , nitrogen , chemical decomposition , inorganic chemistry , chemistry , amorphous silica , reaction rate , materials science , reaction mechanism , chemical engineering , analytical chemistry (journal) , catalysis , metallurgy , crystallography , organic chemistry , engineering
The reaction between amorphous silica and ammonia in the temperature range 200° to 1230°C has been investigated. The reaction process was monitored with respect to the nitrogen content of the reaction product, the specific surface area of the amorphous nitrided silica, and the decomposition of ammonia. A surface reaction was observed at temperatures between 300° and 500°C, but in agreement with other studies bulk reaction only occurred above 800°C, reaching its maximum rate at about 1000°C. It is suggested that the decomposition of ammonia, which also becomes important above 800°C, is essential for the bulk nitridation reaction. At temperatures above 1050°C the nitridation yield decreases, until gas‐phase reaction between SiO( g ) and N 2 or NH 3 becomes dominant at 1230°C, leading to the formation of α‐Si 3 N 4 .