Inspired articular structure for enhancing high-temperature abrasibility of as-sprayed YSZ/BN-polyester sealing coating

Abstract

Designing and preparing engineering abradable seal coatings (ASCs) with excellent abrasibility and adequate mechanical stability at extremely high temperatures is exceptionally challenging. Inspired by the unique structural features of articulation, we designed a YSZ/BN-polyester coating with polyester to form a cancellous-like structure and a smooth “glaze” layer to form a cartilage-like structure-combined, the two formed an ASC with improved abrasibility at both room temperature and a high temperature of 1000 °C. The cancellous-like structure in the YSZ/BN-polyester coating effectively reduced the number of spalling pits caused by stress concentration and brittle fracture, which contributed to a reduction in the coefficient of friction (COF, 0.33) at room temperature. At 1000 °C, the wear debris rich in h-BN and B₂O₃ produced by the oxidation of h-BN compressed to form a cartilage-like smooth “glaze” layer. Moreover, B₂O₃, as a “sintering agent”, improved the stability of the cartilage-like structure and caused “healing”, which effectively reduced the COF (0.22) and its fluctuation amplitude at 1000 °C. The cartilage-like structure helped to improve the mechanical stability of the coating, which further extended the service durability of the YSZ/BN-polyester sealing coating. Thus, the YSZ/BN-polyester coating with an articulation-mimicking structure demonstrates significant promise for the development of a high-temperature ASC system.