Longitudinal Hole Forming Method and Thermal Barrier Coatings Based on Inverse Deformation of Layered Thermal Barrier Coatings

Abstract

The invention discloses a longitudinal hole-forming method of a layered thermal barrier coating based on reverse deformation and a thermal barrier coating. The layered thermal barrier coating with low thermal conductivity is prepared by using a conventional plasma spraying process, and then adopts The method of reverse deformation forms transverse tensile stress in the coating, and forms large-scale longitudinal pores along the heat flow direction in the layered thermal barrier coating. The pore depth is 20% to 100% of the coating thickness, and the pore interval is 0.5 to 10 times the thickness. In high-temperature service environment, the layered structure with low thermal conductivity can effectively block heat flow and play a role of high heat insulation; while the large-scale longitudinal pores can significantly reduce the overall rigidity of the coating in high-temperature service, thereby passing through the low-induced The cracked design has the effect of greatly extending the service life of the coating. The invention achieves the purpose of forming large-scale longitudinal pores in the high heat insulation layered thermal barrier coating at low temperature, and is expected to achieve the synergistic optimization effect of high heat insulation and long life.

Description

technical field [0001] The invention relates to the technical field of coatings, in particular to a preparation method of a thermal barrier coating and a thermal barrier coating. Background technique [0002] Thermal barrier coatings are widely used in aero-engines and ground-based gas turbines. The main function is to reduce the bearing temperature of metal-based hot end components and prevent them from failing in an environment higher than their own temperature-bearing limit. For example, at present, the turbine inlet temperature of H-class heavy-duty gas turbines has reached 1600°C, and the temperature-bearing capacity of the hot-end components is required to reach more than 1400°C. However, the temperature limit of current state-of-the-art single crystal superalloys is only about 1100°C. Therefore, corresponding cooling protection measures must be taken to ensure the stable operation of the hot end components. Thermal barrier coating is one of the necessary thermal ins...

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Problems solved by technology

Existing methods mainly focus on two aspects: (1) Obtain a relatively dense structure, densify the structure, obtain a large pore-forming stress by increasing the apparent elastic modulus, and then form pores longitudinally; however, the relatively dense structure It inevitably sacrifices the thermal insulation ability of the coating in the longitudinal direction; (2) Increase the pretreatment temperature of the coating (mostly 800°C to 1400°C) to obtain a larger shrinkage deformation, thereby increasing the pore-forming stress, but the higher temperature It often inevitably causes the sintering and densification of the coating, and also has a certain weakening effect on the heat insulation of the coating.

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