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Effect of AlN Substitutions on the Oxidation Behavior of ZrB 2 –SiC Composites at 1600°C
Author(s) -
Ouyang Gaoyuan,
Ray Pratik K.,
Kramer Matthew J.,
Akinc Mufit
Publication year - 2016
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/jace.14345
Subject(s) - materials science , isothermal process , composite material , oxygen , oxidation process , degradation (telecommunications) , chemical engineering , chemistry , telecommunications , physics , organic chemistry , computer science , engineering , thermodynamics
The oxidation behavior of ZrB 2 –SiC composites, with varying amounts of AlN substituting for ZrB 2 , was studied isothermally under static ambient air at 1600°C for up to 5 h. Small amounts of AlN substitutions (≤10 vol%) were found to result in marginal improvement in the oxidation resistance, whereas larger amounts resulted in a significant deterioration. The size of ZrO 2 clusters formed on the oxidized surface was found to be a function of the AlN content. This effect was more pronounced after longer oxidation times (~1 h) as opposed to shorter durations (~5 min). It was postulated that presence of AlN results in the formation of Al 2 O 3 during the oxidation process, subsequently resulting in a lowering of viscosity of the glassy silica scale, which facilitates the coarsening of ZrO 2 clusters. This also increases oxygen permeation through the scale which adversely affects the oxidation resistance of the high AlN content composites.