Self-Healing and Thermal Stability of LaMgAl11O19-Ti3AlC2 Composites for High-Temperature Abradable Applications
Author:
Huang Jingqi1ORCID, Chen Wenbo1, Lü Kaiyue1, Xu Mingyi1, Deng Longhui1, Jiang Jianing1, Dong Shujuan1, Chen Meizhu1, Cao Xueqiang1
Affiliation:
1. State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China
Abstract
Defects such as interconnected pores and cracks can improve the abradability of ceramic-based abradable sealing coatings (ASCs) but may reduce the lifetime. Self-healing can potentially close cracks and transform interconnected pores into isolated ones through filling and sintering effects. Ti3AlC2 (TAC) was incorporated into LaMgAl11O19 (LMA) as both the self-healing agent and sintering aid, and plasma-sprayed LMA-based composite coatings were annealed at 1200 °C to assess their self-healing capabilities and then subjected to oxidation in air and corrosion in steam at 1300 °C to study their long-term stability. Results indicated that increasing TAC content significantly enhances self-healing effectiveness, evidenced by the closure of cracks and the isolation of pores. Oxidation and corrosion at 1300 °C led to significant grain growth and the formation of equiaxed grains with an aspect ratio of approximately 3, which may impair the toughening mechanism. Meanwhile, due to the preferential volatilization of Al in a steam environment, LTA decomposed into α-La2/3TiO3 and La4Ti3O12 phases, and the accelerated mass transfer also resulted in grain coarsening. Interestingly, the L20T composite coating with a porosity of 32.17 ± 0.94% and a hardness of 74.88 ± 1.55 HR15Y showed great potential for abradable applications due to its stable phase composition and uniform pore distribution.
Funder
National Natural Science Foundation of China Major Program (JD) of Hubei Province Key Research and Development Program of Hubei Province
Reference59 articles.
1. Sporer, D., Wilson, S., Giovannetti, I., Refke, A., and Giannozzi, M. (2007, January 11–13). On The Potential of Metal and Ceramic Based Abradables in Turbine Seal Applications. Proceedings of the Thirty-Sixth Turbomachinery Symposium, College Station, Texas, USA. 2. Development and Investigation on New Composite and Ceramic Coatings as Possible Abradable Seals;Bardi;J. Therm. Spray Technol.,2008 3. A Perspective on Thermally Sprayed Thermal Barrier Coatings: Current Status and Trends;Bakan;J. Therm. Spray Technol.,2022 4. YSZ-Polyester Abradable Coatings Manufactured by APS;Aussavy;J. Therm. Spray Technol.,2016 5. Sporer, D.R., Taeck, U., Dorfman, M.R., Nicoll, A.R., Giannozzi, M., and Giovannetti, I. (2006, January 8–11). Novel Ceramic Abradable Coatings with Enhanced Performance. Proceedings of the ASME Turbo Expo 2006: Power for Land, Sea, and Air, Barcelona, Spain.
|
|