Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study
The susceptibility of MAX phases to thermal dissociation at 1300-1550 °C in high vacuum has been studied using in-situ neutron diffraction. Above 1400 °C, MAX phases decomposed to binary carbide (e.g. TiCx) or binary nitride (e.g. TiNx), primarily through the sublimation of A-elements such as Al or...
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| Format: | Journal Article |
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Australasian Ceramic Society
2011
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| Online Access: | http://hdl.handle.net/20.500.11937/35358 |
| _version_ | 1848754476011225088 |
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| author | Low, It-Meng (Jim) Pang, W. |
| author_facet | Low, It-Meng (Jim) Pang, W. |
| author_sort | Low, It-Meng (Jim) |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The susceptibility of MAX phases to thermal dissociation at 1300-1550 °C in high vacuum has been studied using in-situ neutron diffraction. Above 1400 °C, MAX phases decomposed to binary carbide (e.g. TiCx) or binary nitride (e.g. TiNx), primarily through the sublimation of A-elements such as Al or Si, which results in a porous surface layer of MXx being formed. Positive activation energies were determined for the decomposition of MAX phases except for Ti3AlC2 where negative activation energy of 71.9 kJ mol-1 was obtained due to formation of fine pores on TiCx. The kinetics of isothermal phase decomposition at 1550 °C was modelled using a modified Avrami equation. An Avrami exponent (n) of < 1.0 was determined, indicative of the highly restricted diffusion of Al or Si between the channels of M6X octahedra. The characteristics of thermal stability and phase transition are discussed. |
| first_indexed | 2025-11-14T08:41:01Z |
| format | Journal Article |
| id | curtin-20.500.11937-35358 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:41:01Z |
| publishDate | 2011 |
| publisher | Australasian Ceramic Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-353582017-03-08T13:13:17Z Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study Low, It-Meng (Jim) Pang, W. activation energy decomposition neutron diffraction Avrami kinetics MAX phases The susceptibility of MAX phases to thermal dissociation at 1300-1550 °C in high vacuum has been studied using in-situ neutron diffraction. Above 1400 °C, MAX phases decomposed to binary carbide (e.g. TiCx) or binary nitride (e.g. TiNx), primarily through the sublimation of A-elements such as Al or Si, which results in a porous surface layer of MXx being formed. Positive activation energies were determined for the decomposition of MAX phases except for Ti3AlC2 where negative activation energy of 71.9 kJ mol-1 was obtained due to formation of fine pores on TiCx. The kinetics of isothermal phase decomposition at 1550 °C was modelled using a modified Avrami equation. An Avrami exponent (n) of < 1.0 was determined, indicative of the highly restricted diffusion of Al or Si between the channels of M6X octahedra. The characteristics of thermal stability and phase transition are discussed. 2011 Journal Article http://hdl.handle.net/20.500.11937/35358 Australasian Ceramic Society restricted |
| spellingShingle | activation energy decomposition neutron diffraction Avrami kinetics MAX phases Low, It-Meng (Jim) Pang, W. Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study |
| title | Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study |
| title_full | Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study |
| title_fullStr | Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study |
| title_full_unstemmed | Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study |
| title_short | Kinetics of Phase Decomposition in MAX Phases - A Comparative Diffraction Study |
| title_sort | kinetics of phase decomposition in max phases - a comparative diffraction study |
| topic | activation energy decomposition neutron diffraction Avrami kinetics MAX phases |
| url | http://hdl.handle.net/20.500.11937/35358 |