Abstract:In this paper, the relationship between porosity and mechanical properties of porous YSZ abradable seal coatings was investigated. Self-supported YSZ coating specimens with different porosities for three-point bending experiments were successfully prepared by using high-energy plasma spraying technology to prepare YSZ coatings with different porosities on the surface of nickel-based high-temperature alloys, and complete peeling of the coatings from the substrate was achieved, and some mechanical properties of the self-supported YSZ coating specimens at room temperature and 1060℃ were investigated by using three-point bending experiments. The results showed that the fracture toughness of the prepared coating ranged from 12.48 MPa·m1/2 to 20.96 MPa·m1/2 at room temperature, the flexural strength ranged from 17.10 MPa to 43.75 MPa, the elastic modulus ranged from 3.64 GPa to 13.13 GPa when the porosity of the prepared coating ranged from 11.61% to 28.80%. The fracture toughness of the coating at 1060 ℃ ranged from 9.79 MPa·m1/2 to 13.71 MPa·m1/2, the flexural strength ranged from 20.20 MPa to 35.12 MPa, and the elastic modulus ranged from 5.15 GPa to 11.00 GPa. With the increase of porosity, the fracture toughness of the coating increased and the flexural strength and elastic modulus decreased. At medium and low porosity, the flexural strength, elastic modulus and fracture toughness of the coating at high temperature were lower than room temperature, and at high porosity, the flexural strength and elastic modulus of the coating at high temperature conditions were higher than room temperature. Meanwhile, with the increase of porosity, the change trend of mechanical properties of coatings at high temperature conditions was more flat compared with that of room temperature.