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Strengthening and Prevention of Oxidation of Aluminum Nitride by Formation of a Silica Layer on the Surface
Author(s) -
Koh YoungHag,
Choi JongJin,
Kim HyounEe
Publication year - 2000
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.1151-2916.2000.tb01190.x
Subject(s) - layer (electronics) , materials science , nitride , aluminium , ceramic , surface layer , atmosphere (unit) , chemical engineering , composite material , metallurgy , physics , engineering , thermodynamics
A silica (SiO 2 ) layer was deposited on the surface of an AlN ceramic in order to increase the strength and to prevent the high‐temperature oxidation of the material. The layer was formed on the surface by exposing coupons to the atmosphere downstream of a bed of SiC powder in a flowing H 2 –0.1% H 2 O atmosphere at 1450°C. A reaction between the SiC powder and H 2 O in the H 2 gas resulted in the generation of SiO 2 “smoke” in the product gas stream. Part of the SiO 2 smoke was subsequently deposited on the surface of the AlN specimen to form a dense and uniform SiO 2 layer. The strength of AlN was improved by about 20% apparently because of blunting of surface defects by SiO 2 . More importantly, the layer was very effective in protecting the AlN from the oxidation at elevated temperatures, through the inhibition of transport of oxidants to the sample surface.