Substrate-constrained effect on the stiffening behavior of lamellar thermal barrier coatings. Issue 6 (June 2018)

• Record Type: Journal Article
• Authors: Li, Guang-Rong; Lei, Juan; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu
• Is Part Of: Journal of the European Ceramic Society. Volume 38:Issue 6(2018)
• Page Start: 2579
• Page End: 2587
• Publication Date: 2018-06
• Subjects: Substrate constraint -- Constrained healing -- Stiffening -- Thermal barrier coatings -- Structural evolution; 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.2018.01.028
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Thermal exposure would compromises the compliance and thermal insulating performance of thermal barrier coatings (TBCs). However, most publications were based on free-standing coatings in which the stress resulting from substrate is essentially different from TBCs on superalloy substrate. In this paper, the constrained effect of substrate on the ceramic top-coat of plasma sprayed lamellar TBCs was investigated. Results showed that the structural changes evolve from micro-scale to macro-scale during thermal exposure. In a relatively shorter thermal exposure stage, the inter-splat pores became narrowed, whereas the intra-splat cracks became widened. Consequently, the healing kinetics of inter-splat pores was much faster than that of the intra-splat cracks. In a relatively longer thermal exposure stage, some macroscale cracks appeared in coating surface owing to the gradually stiffening coatings. As a result, the microscale intra-splat cracks near the macroscale cracks were healed rapidly. In brief, the substrate constraint induced structural changes were stage sensitive.