Method for reducing surface roughness of metal bonding layer of thermal barrier coating

Abstract

The invention belongs to the technical field of aero-engine coatings, and relates to a method for reducing the surface roughness of a metal bonding layer of a thermal barrier coating, an MCrAlY metal bonding layer is prepared on a base material, a sic abrasive is adopted for surface finishing treatment to reduce the surface roughness of the metal bonding layer, the bonding strength of the thermal barrier coating and the base material is improved, and the service life of the thermal barrier coating and the base material is prolonged. The method comprises the steps of surface finishing treatment, cleaning, dewatering and drying. Surface finishing treatment process parameters are selected as follows: the granularity of a SiC abrasive material is (150 + / -50) mu m, and the main frequency is (60 + / -15) Hz; the total surface finishing time is (30 + / -15) min; the forward rotation time is (60 + / -15) s; the reversal time is 60 + / -15 s, and the polished metal bonding layer is taken out. According to the method for reducing the surface roughness of the metal bonding layer, the coating has more excellent bonding force, meanwhile, the roughness of the coating can be reduced, and finally the performance of the coating is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engine coating materials and relates to a method for reducing the surface roughness of a metal bonding layer of a thermal barrier coating. Background Art

[0002] At present, with the continuous improvement of the thrust and working efficiency of gas turbines, the gas intake temperature is getting higher and higher, and the working temperature of nickel-based high-temperature alloys used in turbine blades and other hot end components has gradually approached its service temperature limit. Thermal barrier coatings (TBCs) are a surface protection technology that utilizes the high temperature resistance, erosion resistance, corrosion resistance and low thermal conductivity of ceramic materials and combines them with metal substrates in the form of coatings to increase the working temperature of metal parts, enhance the high temperature resistance of hot end components, extend the service life of hot end components, and improve the working efficiency of the engine. However, the long-term use of the next generation of high-performance aircraft engine thermal barrier coating materials still has problems with unstable life and foreign matter adhesion. Therefore, studying the method of reducing the surface roughness of thermal barrier coatings has become the key to developing thermal barrier coatings that can improve the performance of aircraft engines. Summary of the invention

[0003] The purpose of the present invention is to provide a method for reducing the surface roughness of the metal bonding layer of a thermal barrier coating in view of the above-mentioned deficiencies in the prior art. The purpose is to reduce the surface roughness of the thermal barrier coating, improve the bonding strength and improve the coating life by surface finishing.

[0004] To solve this technical problem, the technical solution of the present invention is:

[0005] A method for reducing the surface roughness of a metal bonding layer of a thermal barrier coating is provided, wherein the surface roughness reducing method comprises:

[0006] Load the surface finishing equipment, select SiC abrasive with a particle size of (150±50)μm and a main frequency of (60±15)Hz; the total surface finishing time is (30±15)min; the forward rotation time is (60±15)s; the reverse rotation time is (60±15)s, and the metal bonding layer after finishing is taken out.

[0007] The coating system is a MCrAlY metal bonding layer.

[0008] The matrix material is a nickel-based high-temperature alloy material.

[0009] The coating preparation method is supersonic flame spraying or vacuum arc plating

[0010] The method further comprises the steps of washing and dehydrating and drying.

[0011] The cleaning steps are as follows: soak the coating in a 10±5% water-based cleaning agent for 60±10 minutes, and then soak the thermal barrier coating in deionized water for 60±10 minutes.

[0012] Preferably, the water-based cleaning agent is a degreasing agent with a pH of 7±0.5.

[0013] The dehydration and drying steps are as follows: take out and put into an oven, and dry at 80±10°C for 30±5min. Soak the coating in an organic solvent for 30±5min, then take out and put into an oven, and dry at 80±10°C for 30±5min.

[0014] Preferably, the organic solvent is acetone or ethanol, and the purity is analytical grade.

[0015] The present invention has the following advantages and beneficial effects:

[0016] The present invention discloses a method for reducing the surface roughness of a metal bonding layer of a thermal barrier coating. The method adopts SiC abrasives and controls the main frequency, surface finishing time, forward rotation time and reverse rotation time to reduce the surface roughness of the coating and improve its uniformity, thereby improving the bonding strength of the thermal barrier coating and ultimately improving the service life of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions implemented in the present invention, the following is a brief explanation of the drawings required to be used in the examples of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 The appearance change of the thermal barrier coating before and after surface finishing of Example 1; Figure 1 It can be seen that after surface finishing, the coating presents a metallic bright color, indicating that the roughness is reduced evenly.

[0019] Figure 2 The coating bonding strength changes of Examples 1, 2, 3 and Comparative Example; Figure 2 It can be seen that the surface finishing method improves the coating bonding strength to more than 15 MPa. Compared with other embodiments, the comparative example changes the main frequency and time, so the bonding strength is reduced.

[0020] Figure 3 The coating life changes of Examples 1, 2, 3 and the comparative example; Figure 3 It can be seen that the surface finishing method increases the coating life by more than 100 hours. Compared with other embodiments, the main frequency and time are changed in the comparative example, so the coating life is reduced.

[0021] Table 1 shows the coating roughness changes of Examples 1, 2, 3 and the comparative example. It can be seen from Table 1 that the surface finishing method is used to reduce the coating surface roughness by more than 1.0 μm. Compared with other embodiments, the comparative example changes the main frequency and time, so the coating surface roughness is improved. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] The features of various aspects of the embodiments of the present invention will be described in detail below. In the following detailed description, many specific details are provided to provide a comprehensive understanding of the present invention. However, it is obvious to a person skilled in the art that the present invention can also be implemented without these specific details. The technical solution of the invention will be further described in detail below in conjunction with the embodiments:

[0024] The process conditions in the washing and dehydration and drying steps in the embodiment of the present invention and the comparative example are the same, and the steps are as follows:

[0025] ⑴. MCrAlY metal bonding layer coating: prepared by supersonic flame spraying or vacuum arc plating, and then the coating surface is polished.

[0026] ⑵. Cleaning: Soak the surface after finishing in 10% water-based cleaning agent for 60 minutes, and then soak the coating in deionized water for 60 minutes. The water-based cleaning agent is a degreasing agent with a pH of 7. The water-based cleaning agent is specifically an environmentally friendly water-based cleaning agent, a multi-purpose water-based cleaning agent or a strong water-based cleaning agent;

[0027] ⑶. Dehydration and drying: Soak the thermal barrier coating in an organic solvent for 30 minutes, then take it out and put it in an oven, and dry it at 80°C for 30 minutes. The organic solvent is acetone or ethanol with analytical purity.

[0028] Embodiment 1:

[0029] Coating surface finishing treatment: The metal bonding layer is loaded into the surface finishing treatment equipment, the main frequency is 45Hz; the total surface finishing time is 45min; the forward rotation time is 60s; the reverse rotation time is 60s. The metal bonding layer is NiCrAlYSi coating. The abrasive is SiC abrasive with a particle size of 120-150μm.

[0030] Embodiment 2:

[0031] Coating surface finishing treatment: The metal bonding layer is loaded into the surface finishing treatment equipment, the main frequency is 60Hz; the total surface finishing time is 30min; the forward time is 75s; the reverse time is 75s. The metal bonding layer is NiCoCrAlYHf coating. The abrasive is SiC abrasive with a particle size of 150-180μm.

[0032] Embodiment 3:

[0033] Coating surface finishing treatment: The metal bonding layer is loaded into the surface finishing treatment equipment, the main frequency is 75Hz; the total surface finishing time is 20min; the forward time is 45s; the reverse time is 45s. The metal bonding layer is NiCoCrAlYTa coating. The abrasive is SiC abrasive with a particle size of 130-160μm.

[0034] Comparative Example:

[0035] Coating surface finishing treatment: The metal bonding layer is loaded into the surface finishing treatment equipment, the main frequency is 15Hz; the total surface finishing time is 100min; the forward rotation time is 60s; the reverse rotation time is 60s. The metal bonding layer is NiCrAlYSi coating. The abrasive is SiC abrasive with a particle size of 150-180μm.

[0036] Figure 1 The appearance change of the thermal barrier coating before and after surface finishing of Example 1; Figure 2 The thermal barrier coating bonding strengths of Examples 1, 2, 3 and the comparative example are shown. Figure 3 Shown are the changes in thermal barrier coating life of Examples 1, 2, 3 and the comparative example.

[0037] Table 1

[0038] sample Before surface finishing (μm) After surface finishing (μm) Comparative Example 2.7 2.0 Example 1 2.5 0.8 Example 2 2.6 0.7 Example 3 2.8 0.9

[0039] Table 1 shows the coating roughness changes of Examples 1, 2, 3 and the comparative example; it can be seen that due to the difference in the main frequency of surface finishing and the finishing time, the coating bonding strength in the comparative example is only 52.5MPa, and the life is 600 hours. The combination of the main frequency of surface finishing and the finishing time parameters in Examples 1, 2 and 3 makes the coating bonding strength above 70MPa. In the surface finishing process of the embodiment of the present invention, a combination of forward and reverse rotation is adopted to achieve a uniform reduction in the roughness of the thermal barrier coating, and an improvement in bonding strength and life. On the other hand, from Figure 2 It can also be seen that since the main frequency and polishing time are changed in the comparative example compared with Examples 1, 2, and 3, it is found that the thermal barrier bonding strength and life are greatly reduced.

[0040] By adopting surface finishing technology, through the control of main frequency, finishing time, and forward and reverse time, the integrity of the thermal barrier coating can be maintained, the bonding strength of the thermal barrier coating can be improved to 70MPa, and ultimately the coating life can be increased to 800 hours.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for reducing the surface roughness of a metal bonding layer of a thermal barrier coating, characterized in that: The surface treatment method process is as follows: The coating was loaded into a surface finishing machine with a main frequency of (60±15) Hz; abrasive was used for treatment, and the total surface finishing time was (30±15) min; forward rotation time was (60±15) s; and reverse rotation time was (60±15) s.

2. The method according to claim 1, characterized in that: The coating system is a MCrAlY metal bonding layer.

3. The method according to claim 1, characterized in that: The abrasive is SiC abrasive with a particle size of (150±50) μm.

4. The method according to claim 1, characterized in that: The matrix material is a nickel-based high-temperature alloy material.

5. The method according to claim 1, characterized in that: The MCrAlY metal bonding layer is prepared on the base material by supersonic flame spraying or vacuum arc plating.

6. The method according to claim 1, characterized in that: The method for reducing surface roughness further comprises the steps of re-cleaning and dehydrating and drying after the surface treatment.

7. The method according to claim 1, characterized in that: The cleaning steps are as follows: soak the coating in a 10±5% water-based cleaning agent for 60±10 minutes, and then soak the thermal barrier coating in deionized water for 60±10 minutes.

8. The method according to claim 7, characterized in that: The water-based cleaning agent is a degreasing agent with a pH of 7±0.

5.

9. The method according to claim 7, characterized in that: The dehydration and drying steps are as follows: soak the coating in an organic solvent for 30±5 minutes, then take it out and put it in an oven, and dry it at 80±10° C. for 30±5 minutes.

10. The method according to claim 8, characterized in that: The organic solvent is acetone or ethanol, and its purity is analytical grade.

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