Preparation of long-lifetime thermal barrier coatings and toughening mechanism by using hierarchy structured zirconia-based microspheres. Issue 8 (July 2021)

• Record Type: Journal Article
• Authors: Zhang, Ruiji; Zhang, Xing; Xing, Chen; Hu, Li; Guo, Fangwei; Wang, Xin; Zhao, Xiaofeng
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 8(2021)
• Page Start: 4625
• Page End: 4636
• Publication Date: 2021-07
• Subjects: Thermal barrier coatings -- Yttria stabilized zirconia -- Air plasma spray -- Electro-sprayed -- Microstructure; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.03.003
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: The thermal cycling lifetime of thermal barrier coatings was doubled when deposited by electro-sprayed (ESP) microspheres instead of by commercial hollow spherical powders. It was believed that partial-molten nodules with featured microstructures inherited from the feedstock microspheres were the main contributor for prolonged thermal cycling durability due to improved fracture toughness and strain tolerance. The maximum lifetime was observed on samples with 20−30 vol.% of partial-molten microspheres. The hierarchy pores may both slow down the crack propagation by triggering multi-deflecting and promote cracking by reducing the tendency of interfacial deflection, the net effect depends on situation. The ESP coatings exhibited bimodal Weibull moduli upon indentation, which was regarded as originated from the hierarchy porous structure. Finally, the criterion was verified by micro-indentation and residual stain-stress evaluation by Raman spectroscopy.