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Kinetics and mechanism of the oxidation of ZrSi2-MoSi2-ZrB2 ceramics in air at temperatures up to 1400 °C
[Display omitted] •Combination of SHS and HP use to obtain ceramics in the ZrSi2-MoSi2-ZrB2 system.•Kinetics of oxidation at 1400 °C described using a power function with index n > 2.•Mostly the ZrSi2 phase were oxidized.•Two-layer film formed during oxidation consist of silicate glass and ZrSiO4...
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Published in: | International journal of heat and mass transfer 2019-09, Vol.140, p.12-20 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | [Display omitted]
•Combination of SHS and HP use to obtain ceramics in the ZrSi2-MoSi2-ZrB2 system.•Kinetics of oxidation at 1400 °C described using a power function with index n > 2.•Mostly the ZrSi2 phase were oxidized.•Two-layer film formed during oxidation consist of silicate glass and ZrSiO4 sublayer.•ZrSiO4 with scheelite-type structure encapsulate the ZrB2 and MoSi2.
The results of a study of the kinetics and mechanism of heterogeneous and compact ceramics oxidation in the ZrSi2-MoSi2-ZrB2 system at air temperature of 1400 °C are presented. The ceramics were obtained by the hot-pressing of composite powders that were manufactured by self-propagating high-temperature synthesis following the magnesiothermal recovery approach. Oxidation kinetics are described using a power function with index n>2, confirming the significant influence on the evolution process in the structure of the formed oxidation coating. The oxidation mechanism includes the formation of a two-layer structure consisting of a continuous silicate film, of which the outer part contains magnesium and a sublayer based on the ZrSiO4 phase, with the scheelite structure encapsulating the ZrB2 and MoSi2 grains. The influence of the ZrSi2, MoSi2 and ZrB2 phases on the structural-morphological peculiarities of the appearing oxide films and the effectiveness of its protective action are revealed. |
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ISSN: | 0017-9310 1879-2189 |
DOI: | 10.1016/j.ijheatmasstransfer.2019.05.100 |