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Non‐isothermal and isothermal oxidation behaviors of AlON translucent ceramic in air
Author(s) -
Qi J. Q.,
Xie X. M.,
Wang Y.,
Wang J.,
Xiao L.,
Wei N.,
Wu D.,
Lu T. C.
Publication year - 2015
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201307319
Subject(s) - isothermal process , scanning electron microscope , thermogravimetric analysis , materials science , diffusion , ceramic , analytical chemistry (journal) , activation energy , chemistry , thermodynamics , metallurgy , composite material , chromatography , organic chemistry , physics
The oxidation behavior of AlON translucent ceramic was investigated both in non‐isothermal (from room temperature to 1573 K) and isothermal (at 1373 and 1473 K) conditions. The mass gains, phase compositions and micromorphology of oxidized samples were examined by thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscopy (SEM), respectively. The results suggest that in non‐isothermal environment the oxidation reaction starts at about 1173 K for both AlON bulk sample and powder. In isothermal condition, the mass gain indicates the two‐stage reaction mechanism which starts with chemical reaction, followed by diffusion controlled stage. XRD patterns suggest that AlON is thermodynamically unstable and it partly decomposes into corundum phase Al 2 O 3 and AlN during the oxidation process. SEM results indicate that different micromorphology is obtained at different temperatures in the oxidation process. The estimated apparent activation energy for the diffusion rate controlled stage from isothermal experiment is about 245.2 kJ/mol.