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Hydrothermal Treatment of Si 3 N 4 for the Improvement of Oxidation Resistance at 1400°C
Author(s) -
Lee SeaHoon,
Kaiser Gerhard,
Rixecker Georg,
Aldinger Fritz,
Park JaeYoung,
Auh KeunHo,
Choi SungChurl
Publication year - 2008
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.1551-2916.2007.02189.x
Subject(s) - hydrothermal circulation , autoclave , porosity , materials science , oxide , layer (electronics) , leaching (pedology) , mineralogy , ceramic , chemical engineering , metallurgy , inorganic chemistry , chemistry , composite material , geology , soil water , soil science , engineering
The surface of Si 3 N 4 ceramics was hydrothermally treated with HCl or H 2 SO 4 using an autoclave. The thickness of the oxide layers formed on the Si 3 N 4 samples decreased to one‐fourth after oxidation at 1400°C by the treatment. The oxide layer of the treated samples was dense, and flaw formation in and beneath the layer did not occur at 1400°C. The avoidance of low melting Y‐silicates by leaching Y 2 O 3 is the reason for the improved oxidation resistance of the hydrothermally treated Si 3 N 4 , despite an increase in surface porosity through a 70 μm layer.