Heat treatment method for improving binding force of bonding layer of thermal barrier coating

Abstract

The invention belongs to the field of heat treatment, and particularly relates to a heat treatment method for improving the binding force of a thermal barrier coating bonding layer. According to the method, the surface of the bonding layer is treated through a high-energy beam and high-speed heat treatment method according to components of the bonding layer, the heat treatment time of each time is controlled within 10-30 s, asynchronous migration of metal atoms in the bonding layer is achieved through instant high temperature, and finally a wedge-shaped structure is formed on the surface of the bonding layer. The thermal barrier coating bonding layer and the ceramic surface layer have good bonding force, and the use performance of the thermal barrier coating is improved.

Description

Technical Field

[0001] The invention belongs to the field of heat treatment, and in particular relates to a heat treatment method for improving the bonding strength of a bonding layer of a thermal barrier coating. Background Art

[0002] In order to meet the temperature requirements of high thrust-to-weight ratio of aircraft engines, on the one hand, the most advanced air film cooling technology is needed, and on the other hand, thermal barrier coatings need to be applied on the blade surface to reduce the temperature of the base material. At present, thermal barrier coatings usually use MCrAlY or platinum aluminum coatings as bonding layers, and use Y2O3 partially stabilized ZrO2 as the ceramic outer layer. The isolation effect of the outer layer can reduce the surface temperature of the coating by about 150°C, so that the thermal barrier coating system gradually meets the application requirements.

[0003] A typical thermal barrier coating system consists of four layers: a ceramic layer, a thermally grown oxide film, a bonding layer, and a high-temperature alloy substrate. The interaction between the four layers affects the service life of the thermal barrier coating. First, during the service of the coating, thermal stress is generated between the generated oxide film and the coating due to the different thermal expansion coefficients, which leads to cracking and peeling of the oxide film, seriously affecting the service performance of the coating. Second, when the service temperature exceeds 1000 °C, the interface between the bonding layer and the alloy substrate will diffuse elements due to the large difference in chemical composition, accelerating the degradation of the coating, thereby slowing down the service life of the coating and causing the coating to fail. Therefore, it is necessary to improve the bonding strength between the metal bonding layer of the thermal barrier coating and the ceramic surface layer. Summary of the invention

[0004] In view of the problems in the prior art, the present invention provides a heat treatment method for improving the bonding strength of a bonding layer of a thermal barrier coating.

[0005] The technical solution of the present invention is: A heat treatment method for improving the bonding strength of a thermal barrier coating bonding layer comprises the following steps: Step (1) cleaning the surface of the bonding layer to ensure that there are no surface defects on the bonding layer that affect the quality of heat treatment; Step (2) treats the surface of the bonding layer multiple times using a high-energy beam and high-speed heat treatment method according to the material composition of the bonding layer. The heat treatment time for each time is controlled within 10 to 30 seconds. The high-energy beam action temperature range is 800 to 2000°C. The instantaneous high temperature causes the metal atoms in the bonding layer to migrate asynchronously, and finally forms a wedge-shaped structure on the surface of the bonding layer.

[0006] Furthermore, in the above-mentioned heat treatment method for improving the bonding strength of the bonding layer of the thermal barrier coating, in step (2), the specific method of using the high-energy beam and high-speed heat treatment method to repeatedly treat the surface of the bonding layer is as follows: first, using a low-frequency and high-energy beam heat treatment method to activate the particles on the surface of the bonding layer, the temperature is controlled at 800°C to 1000°C, and the heat treatment time is controlled within 20 seconds, so that the surface of the bonding layer is melted to form a specific molten pool; adjusting the temperature of the high-energy beam, and then using a high-frequency and high-energy beam heat treatment method to quickly and alternately heat treat the activated surface of the bonding layer, the temperature is controlled at 1000°C to 2000°C, and the heat treatment time for each time is controlled within 10 seconds, and using different temperatures to alternately radiate the surface of the bonding layer multiple times to form molten pools of different shapes on the surface of the bonding layer, and finally forming a wedge-shaped structure on the surface of the bonding layer.

[0007] Advantages and beneficial effects of the present invention: 1. The heat treatment process of the present invention has the advantages of low cost, rapidity, simplicity and energy saving; 2. After the thermal barrier coating bonding layer after heat treatment of the present invention is coated on the ceramic surface layer, its bonding strength is greatly improved, thereby extending the service life of the thermal barrier coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of a wedge-shaped structure obtained on the surface of the bonding layer after being treated by the heat treatment method of the present invention; Figure 2 It is a schematic diagram of the bonding layer coated with a ceramic surface layer after being treated by the heat treatment method of the present invention. DETAILED DESCRIPTION

[0009] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but cannot be used to limit the scope of the present invention. Example 1

[0010] The composition of the bonding layer in this embodiment is NiCrAlY, and the heat treatment method for improving the bonding strength of the bonding layer specifically includes the following steps: Step (1) cleaning the surface of the bonding layer to ensure that the bonding layer has no surface defects such as knocks, bruises, cracks, pits, etc. that may affect the quality of the surface heat treatment; Step (2) activating the particles on the surface of the bonding layer by low-frequency, high-energy beam heat treatment, the temperature is 1000°C, and the heat treatment time is 20s; Step (3) using high frequency and high energy beam heat treatment methods to rapidly and alternately heat treat the surface of the activated bonding layer: the temperature is 1800°C, the heat treatment time is controlled to be 10s; the temperature is 1500°C, the heat treatment time is controlled to be 10s; the temperature is 1300°C, the heat treatment time is controlled to be 10s; and this process is repeated until the bonding layer surface is finally obtained as shown in FIG. Figure 1The wedge-shaped structure shown in FIG. 1 is used to apply the bonding layer to the ceramic surface layer. The schematic diagram is shown in FIG. Figure 2 As shown, a ceramic surface layer is prepared on the surface of the bonding layer forming the wedge-shaped structure, so that the interface between the ceramic surface layer and the bonding layer is more tightly bonded through the wedge-shaped structure. Example 2

[0011] The component of the bonding layer in this embodiment is PtAl, and the heat treatment method for improving the bonding strength of the bonding layer specifically includes the following steps: Step (1) cleaning the surface of the bonding layer to ensure that the bonding layer has no surface defects such as knocks, bruises, cracks, pits, etc. that may affect the quality of the surface heat treatment; Step (2) activating the particles on the surface of the bonding layer by low-frequency, high-energy beam heat treatment, the temperature is 800°C, and the heat treatment time is 20s; Step (3) uses high-frequency and high-energy beam heat treatment methods to rapidly and alternately heat treat the surface of the activated bonding layer: the temperature is 1200°C, and the heat treatment time is controlled to be 10 s; the temperature is 1100°C, and the heat treatment time is controlled to be 10 s; the temperature is 1000°C, and the heat treatment time is controlled to be 10 s; and this process is repeated until a wedge-shaped structure is finally obtained on the surface of the bonding layer, and the bonding layer is coated on the ceramic surface layer, and a ceramic surface layer is prepared on the surface of the bonding layer with the wedge-shaped structure, so that the interface between the ceramic surface layer and the bonding layer is more tightly bonded through the wedge-shaped structure.

Claims

1. A heat treatment method for improving the bonding strength of a thermal barrier coating adhesive layer, characterized in that: The following steps are involved: Step (1) cleaning the surface of the bonding layer to ensure that there are no surface defects on the bonding layer that affect the quality of heat treatment; Step (2) treats the surface of the bonding layer multiple times using a high-energy beam and high-speed heat treatment method according to the material composition of the bonding layer. The heat treatment time for each time is controlled within 10 to 30 seconds. The high-energy beam action temperature range is 800 to 2000°C. The instantaneous high temperature causes the metal atoms in the bonding layer to migrate asynchronously, and finally forms a wedge-shaped structure on the surface of the bonding layer.

2. A heat treatment method for improving the bonding strength of a thermal barrier coating adhesive layer according to claim 1, characterized in that: In step (2), the specific method of using high-energy beam and high-speed heat treatment method to treat the surface of the bonding layer multiple times is as follows: first, use low-frequency and high-energy beam heat treatment method to activate the particles on the surface of the bonding layer, control the temperature at 800°C to 1000°C, and control the heat treatment time within 20 seconds, so that the surface of the bonding layer melts to form a specific molten pool; adjust the temperature of the high-energy beam, and then use high-frequency and high-energy beam heat treatment methods to quickly and alternately heat treat the activated surface of the bonding layer, control the temperature at 1000°C to 2000°C, and control the heat treatment time each time within 10 seconds, and use different temperatures to alternately radiate the surface of the bonding layer multiple times to form molten pools of different shapes on the surface of the bonding layer, and finally form a wedge-shaped structure on the surface of the bonding layer.

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