Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium

Zhaoying Ding; Johannes C. Brouwer; Cees Kwakernaak; Jia Ning Zhu; Vera Popovich; Marcel J.M. Hermans; Willem G. Sloof

doi:10.1016/j.matdes.2022.111577

Mo(Al_xSi₁₋_x)₂ healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium

Zhaoying Ding, Johannes C. Brouwer, Cees Kwakernaak, Jia Ning Zhu, Vera Popovich, Marcel J.M. Hermans, Willem G. Sloof^*

^*Corresponding author for this work

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Abstract

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(Al_xSi_1-_x)₂ particles. Healing particles of Mo(Al_xSi_1-_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.

Original language	English
Article number	111577
Number of pages	15
Journal	Materials and Design
Volume	225
DOIs	https://doi.org/10.1016/j.matdes.2022.111577
Publication status	Published - 2023

Keywords

Alumina scale growth
Encapsulation
Mo(Al,Si)
Oxidation
Self-healing thermal barrier coatings

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10.1016/j.matdes.2022.111577

1-s2.0-S026412752201200X-mainFinal published version, 5.98 MBLicence: CC BY

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@article{f47697290d994cf688d681e93809358d,

title = "Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium",

abstract = "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.",

keywords = "Alumina scale growth, Encapsulation, Mo(Al,Si), Oxidation, Self-healing thermal barrier coatings",

author = "Zhaoying Ding and Brouwer, {Johannes C.} and Cees Kwakernaak and Zhu, {Jia Ning} and Vera Popovich and Hermans, {Marcel J.M.} and Sloof, {Willem G.}",

year = "2023",

doi = "10.1016/j.matdes.2022.111577",

language = "English",

volume = "225",

journal = "Materials & Design",

issn = "0264-1275",

publisher = "Elsevier",

}

Mo(Al_xSi₁₋_x)₂ healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium. / Ding, Zhaoying ; Brouwer, Johannes C.; Kwakernaak, Cees ; Zhu, Jia Ning ; Popovich, Vera ; Hermans, Marcel J.M.; Sloof, Willem G.

In: Materials and Design, Vol. 225, 111577, 2023.

Research output: Contribution to journal › Article › Scientific › peer-review

TY - JOUR

T1 - Mo(AlxSi1−x)2 healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium

AU - Ding, Zhaoying

AU - Brouwer, Johannes C.

AU - Kwakernaak, Cees

AU - Zhu, Jia Ning

AU - Popovich, Vera

AU - Hermans, Marcel J.M.

AU - Sloof, Willem G.

PY - 2023

Y1 - 2023

N2 - 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.

AB - 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.

KW - Alumina scale growth

KW - Encapsulation

KW - Mo(Al,Si)

KW - Oxidation

KW - Self-healing thermal barrier coatings

UR - http://www.scopus.com/inward/record.url?scp=85145965806&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2022.111577

DO - 10.1016/j.matdes.2022.111577

M3 - Article

AN - SCOPUS:85145965806

VL - 225

JO - Materials & Design

JF - Materials & Design

SN - 0264-1275

M1 - 111577

ER -

Mo(Al_xSi₁₋_x)₂ healing particles for high temperature ceramics and encapsulation by selective oxidation of aluminium

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