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Fabrication and oxidation behavior of Al 4 SiC 4 powders
Author(s) -
Chen JunHong,
Zhang ZhiHao,
Mi WenJun,
Wang EnHui,
Li Bin,
Chou KuoChih,
Hou XinMei
Publication year - 2017
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.14841
Subject(s) - mullite , materials science , isothermal process , thermogravimetry , oxide , microstructure , spallation , layer (electronics) , silicon , activation energy , calcination , corundum , chemical engineering , fabrication , analytical chemistry (journal) , ceramic , metallurgy , chemistry , composite material , thermodynamics , biochemistry , physics , quantum mechanics , chromatography , neutron , engineering , catalysis , medicine , alternative medicine , pathology
Al 4 SiC 4 powders with high purity were synthesized by heating the powder mixture of aluminum (Al), silicon (Si), and carbon (C) at 1800°C in argon. The microstructure is characterized as platelike single grain. Both the nonisothermal and isothermal oxidation behavior of Al 4 SiC 4 was investigated at 800°C‐1500°C in air by means of thermogravimetry method. It is demonstrated that Al 4 SiC 4 powder possesses good oxidation resistance up to 1200°C and is almost completely oxidized at 1400°C. At 800°C‐1100°C, the oxide scales consist of an Al 2 O 3 outer layer and a transition layer. Al 4 SiC 4 remains the main phase. At 1200°C, some spallation resulting from the increment of Al 2 O 3 and the mismatch of thermal expansion coefficient between different product layers can be observed. Above 1300°C, the oxide layer is composed of two part, i.e., large‐scale Al 2 O 3 crystals (outer layer) and mullite with less amount of SiO 2 (inner layer). The oxidation behavior changes due to the different oxide products. For the reaction kinetics, a new kind of real physical picture model is adopted and obtains a good agreement with the experimental data. The apparent activation energy is calculated to be 176.9 kJ/mol (800°C‐1100°C) and 267.1 kJ/mol (1300°C‐1400°C).