Phase stability, microstructure and mechanical properties of nanostructured yttria stabilized zirconia coatings subjected to moisture degradation. Issue 21 (1st November 2022)

• Record Type: Journal Article
• Authors: Li, Jinming; Zhu, Runwu; Yuan, Jieyan; Lu, Xiangrong; Zhao, Sumei; Xu, Mingyi; Huang, Jingqi; Tu, Yunwei; Jiang, Jianing; Deng, Longhui; Liu, Li; Dong, Shujuan; Cao, Xueqiang
• Is Part Of: Ceramics international. Volume 48:Issue 21(2022)
• Page Start: 31800
• Page End: 31810
• Publication Date: 2022-11-01
• Subjects: Nanostructured YSZ coating -- Hydrothermal degradation -- Phase stability -- Mechanical properties; YSZ yttria stabilized zirconia; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.07.108
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The nanostructured (8 wt%) yttria stabilized zirconia coatings (n-YSZ) were deposited by atmospheric plasma spraying (APS) to study the effect of moisture degradation on the properties of n-YSZ coatings. Variations in phase composition, microstructure and mechanical properties were comprehensively characterized. The single-edge notched beam method used for fracture toughness testing is sufficiently reliable for evaluating the integral properties of the coatings in this study. Results indicated that the microstructure of the n-YSZ coatings was significantly affected by hydrothermal degradation. Hydrothermal degradation resulted in substantial defects, such as pores and cracks, which severely decreased the mechanical properties of the n-YSZ coatings. In addition, the ceramic coat was in a state of compressive stress, and the stress initially increased and then decreased with increasing degradation time. The variations in the stress of the n-YSZ coatings are closely related to the transformation of tetragonal to monoclinic phase, which is induced by hydrothermal degradation. Additionally, several major mechanical properties of the n-YSZ coatings decreased significantly with the hydrothermal degradation, including fracture toughness from 1.28 ± 0.05 to 0.08 ± 0.01 MPa m 1/2, flexural strength from 60.51 ± 2.98 to 4.54 ± 0.14 MPa, and Young's modulus from 21.98 ± 0.96 to 1.46 ± 0.33 GPa.