Thermal barrier coating with double-layer gradient structure and preparation technology thereof

Abstract

The invention discloses a thermal barrier coating with a double-layer gradient structure. The thermal barrier coating with the double-layer gradient structure comprises a first layered thermal insulation layer positioned inside and a second layered thermal insulation layer positioned outside. The second layered thermal insulation layer is formed by stacking N sublayers, the thermal insulation temperature of each sublayer is equal, and the thermal conductivity of the sublayers of the second layered thermal insulation layer decreases from inside to outside. The first layer thermal insulation layer accounts for 20%-60% of the total thickness of the thermal barrier coating with the double-layer gradient structure, and the fracture toughness of the materials used is greater than or equal to 2.5MPa.m<1 / 2>. The second layer thermal insulation layer accounts for 40%-80% of the total thickness of the thermal barrier coating with the double-layer gradient structure, and the used materials have no phase change at 1200-1600 DEG C, and the thermal conductivity is lower than 1.8W / m.K at 1000-1600 DEG C. The double-layer gradient structure realizes the combination of new materials / new structures,breaks through the reverse restriction relation of the thickness of a single material coating on the thermal insulation capability and the service life, and so that the cooperative design of high thermal insulation, long service life and high temperature resistance of the new structure is achieved.

Description

technical field [0001] The invention belongs to the technical field of coatings, in particular to a thermal barrier coating and a preparation process thereof. Background technique [0002] Thermal barrier coatings (TBCs) are functional coatings for heat insulation, which are mainly applied to the surface of high-temperature hot end components of gas turbines, so as to protect the alloy matrix. The thermal barrier coating can effectively isolate the high-temperature gas from the substrate of the high-temperature hot-end parts, protect the superalloy of the substrate, reduce the surface temperature of the alloy and increase the temperature of the gas at the same time, so the efficiency of the gas turbine is significantly improved. Therefore, TBCs are one of the core technologies of gas turbines. [0003] The two most basic characteristics for evaluating the performance of thermal barrier coatings are their thermal insulation capability and lifetime. The heat insulation abili...

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Problems solved by technology

However, the fracture toughness of new materials is generally poor, which makes the life of TBCs prepared from new materials often very short.

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