Superior Abrasibility of YSZ(ESP)/BN@ZrO₂-Polyester Composite Sealing Coating Reinforcing With Hybrid Micron/Nanometer Multiscaled Pore Structure

Composite materials hold significant potential for abrasive sealing, yet composite materials used for abrasive sealing fall short in service durability under extreme environments. Here, a controllable strategy for adjusting pore structure is proposed, aiming to design a YSZ(ESP)/BN@ZrO₂-polyester coating with hybrid micron/nanometer multiscaled pores to improve the mechanical stability and abradability. By adding porous feedstocks prepared by electrostatic spraying associated with phase inversion (ESP) in conjunction with the control strategy of pore-forming agents, the porosity of the composite coating is achieved at 27.5%, including 45.9% interlayer micropores to enhance abradability, and 54.1% intralayer nanopores to disperse and transfer stress. The BN@ZrO₂ lubricant with core–shell structure in YSZ(ESP)/BN@ZrO₂-polyester effectively increases the operating temperature of BN, ensures its effective release, and forms a smooth “glaze” layer at 1000°C, thereby reducing the coefficient of friction to 0.2. The hybrid micron/nanometer multiscale pores in the coating increase the intrusion depth ratio to −67%, and the uniformly distributed nanopores avoid delamination caused by weak interlayer adhesion, effectively improving high-temperature abradability and service durability. The findings underscore the substantial potential of the proposed YSZ(ESP)/BN@ZrO₂-polyester coating, facilitating applications across diverse domains such as hypersonic aircraft, naval vessels, and ground power generation gas turbine engines.