Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium
To prevent premature triggering of the healing reaction in Mo-Si containing self-healing thermal barrier coating system, an oxygen impenetrable shell (α-Al2O3) around the sacrificial healing particles (MoSi2) is desired. Here an encapsulation method is presented through selective oxidation of Al in...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-01-01
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| Series: | Materials & Design |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S026412752201200X |
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| author | Zhaoying Ding Johannes C. Brouwer Cees Kwakernaak Jia-Ning Zhu Vera Popovich Marcel J.M. Hermans Willem G. Sloof |
| author_facet | Zhaoying Ding Johannes C. Brouwer Cees Kwakernaak Jia-Ning Zhu Vera Popovich Marcel J.M. Hermans Willem G. Sloof |
| author_sort | Zhaoying Ding |
| collection | DOAJ |
| description | To prevent premature triggering of the healing reaction in Mo-Si containing self-healing thermal barrier coating system, an oxygen impenetrable shell (α-Al2O3) around the sacrificial healing particles (MoSi2) is desired. Here an encapsulation method is presented through selective oxidation of Al in Mo(AlxSi1-x)2 particles. Healing particles of Mo(AlxSi1-x)2 is designed in terms of alumina shell thickness, particle size and fraction Al dissolved. By replacing Si by Al in MoSi2 up to the maximum solubility (x = 0.65) a strong crack healing ability is maintained (relative volume expansion ≥ 40 %). The formed exclusive α-Al2O3, featuring a two-layered structure, results from a counter-diffusion process along the grain boundaries, and its oxidation kinetics fits well with the 3D diffusion-Jander model. After 16 h exposure in gaseous ambient with a pO2 of 5 × 10-10 atm. at 1100 °C, a closed and dense shell of α-Al2O3 is formed with a thickness of about 1.3 µm. The oxide shell produced under this condition provided healing particles with significantly improved stability upon exposure to high pO2 of 0.2 atm. at 1100 °C for 50 h. The particles after exposure feature an inner core of MoSi2 with Al completely consumed and an oxide shell of α-Al2O3. |
| first_indexed | 2024-04-10T19:36:18Z |
| format | Article |
| id | doaj.art-1f67d652caba4cf5925b94b267e9f59f |
| institution | Directory Open Access Journal |
| issn | 0264-1275 |
| language | English |
| last_indexed | 2024-04-10T19:36:18Z |
| publishDate | 2023-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj.art-1f67d652caba4cf5925b94b267e9f59f2023-01-30T04:12:41ZengElsevierMaterials & Design0264-12752023-01-01225111577Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminiumZhaoying Ding0Johannes C. Brouwer1Cees Kwakernaak2Jia-Ning Zhu3Vera Popovich4Marcel J.M. Hermans5Willem G. Sloof6Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsDepartment of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsDepartment of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsDepartment of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsDepartment of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsDepartment of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsCorresponding author.; Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the NetherlandsTo prevent premature triggering of the healing reaction in Mo-Si containing self-healing thermal barrier coating system, an oxygen impenetrable shell (α-Al2O3) around the sacrificial healing particles (MoSi2) is desired. Here an encapsulation method is presented through selective oxidation of Al in Mo(AlxSi1-x)2 particles. Healing particles of Mo(AlxSi1-x)2 is designed in terms of alumina shell thickness, particle size and fraction Al dissolved. By replacing Si by Al in MoSi2 up to the maximum solubility (x = 0.65) a strong crack healing ability is maintained (relative volume expansion ≥ 40 %). The formed exclusive α-Al2O3, featuring a two-layered structure, results from a counter-diffusion process along the grain boundaries, and its oxidation kinetics fits well with the 3D diffusion-Jander model. After 16 h exposure in gaseous ambient with a pO2 of 5 × 10-10 atm. at 1100 °C, a closed and dense shell of α-Al2O3 is formed with a thickness of about 1.3 µm. The oxide shell produced under this condition provided healing particles with significantly improved stability upon exposure to high pO2 of 0.2 atm. at 1100 °C for 50 h. The particles after exposure feature an inner core of MoSi2 with Al completely consumed and an oxide shell of α-Al2O3.http://www.sciencedirect.com/science/article/pii/S026412752201200XEncapsulationMo(Al,Si)2Alumina scale growthOxidationSelf-healing thermal barrier coatings |
| spellingShingle | Zhaoying Ding Johannes C. Brouwer Cees Kwakernaak Jia-Ning Zhu Vera Popovich Marcel J.M. Hermans Willem G. Sloof Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium Materials & Design Encapsulation Mo(Al,Si)2 Alumina scale growth Oxidation Self-healing thermal barrier coatings |
| title | Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium |
| title_full | Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium |
| title_fullStr | Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium |
| title_full_unstemmed | Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium |
| title_short | Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium |
| title_sort | mo alxsi1 x 2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium |
| topic | Encapsulation Mo(Al,Si)2 Alumina scale growth Oxidation Self-healing thermal barrier coatings |
| url | http://www.sciencedirect.com/science/article/pii/S026412752201200X |
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