High temperature sealing coating and making method thereof

Abstract

The invention provides a high temperature sealing coating and a making method thereof. The high temperature sealing coating comprises a sealing coating bottom layer and a sealing coating surface layer; the material of the sealing coating bottom layer is NiCoCrWMoSiB high temperature brazing alloy or NiCrCoSiB high temperature brazing alloy; and the material of the sealing coating surface layer comprises 5-12wt% of polyphenyl ester, 5-10wt% BaF2/CaF2, and the balance of NiCrAlYSi alloy or NiCrAlY alloy or NiCoCrAlTaY alloy or CoCrAlY alloy. The making method of the high temperature sealing coating comprises the following steps: making the sealing coating bottom layer on a substrate through cold gas dynamic spraying; making the sealing coating surface layer through plasma spraying; carrying out heat insulation on the substrate sprayed with the high temperature sealing coating at 500DEG C to obtain a pre-product; and carrying out vacuum diffusion treatment on the pre-product at 1150-1250DEG C for 15-30min to complete the production of the high temperature sealing coating. The high temperature sealing coating has the characteristics of low hardness, self lubrication, low friction coefficient and long life, can work at a temperature of 1150DEG C, and can be used for sealing gas paths of aeroengines and ground gas turbine high pressure turbines.

Description

technical field [0001] The invention relates to a high-temperature sealing coating and a preparation method thereof, in particular to a high-temperature sealing coating used for sealing the high-pressure turbine gas path of an aero-engine and a ground gas turbine and a preparation method thereof, belonging to the technical field of surface coatings. Background technique [0002] High-pressure turbine sealing refers to the sealing measures taken to prevent high-temperature gas from leaking from the high-pressure side along the tip of the blade to the low-pressure side. [0003] High-temperature sealing coating, also called high-temperature abradable sealing coating, is a functional coating used to control the gas path clearance of gas turbine engines. The radial gap between the engine turbine casing and the tip of the working blade directly affects the efficiency of the turbine, which has a great impact on the performance of the engine. In order to obtain excellent performanc...

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Problems solved by technology

[0005] Existing plasma spraying 6-8% Y 2 o 3 / ZrO 2 The working temperature of the ceramic-based sealing coating can reach 1100°C, but the coating structure is loose, and it begins to fall off after a short period of work. The working life is short, frequent repairs, and the sealing effect is poor.

And ZrO 2 / 6-8% Y 2 o 3 The high-temperature hardness is high, and the hardness increases significantly with the prolongation of the working time, resulting in serious wear of the engine blades, resulting in a decrease in engine efficiency and thrust

[0006] Although the existing plasma-sprayed nickel-chromium-aluminum-yttrium high-temperature sealing coating has a working temperature of 1100°C, the coating has a large friction coefficient and high hardness, which causes serious wear to the engine blades, and what is more serious is the coating and the outer ring substrate of the turbine. The interface between the parts is mechanically bonded, the coating has low bonding force, and it is easy to peel off and fall off during the working process, which affects the safety of the engine

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