Method for prolonging high-temperature service life of thermal barrier coating of hydrogen-doped gas turbine

Abstract

The invention provides a method for prolonging the high-temperature service life of a thermal barrier coating of a hydrogen-doped gas turbine. The method comprises the steps that Ni, Co, Cr, Fe, Al, Hf, Si and Y are smelted and cast into master alloy according to the proportion; preparing the mother alloy into high-entropy alloy powder through an inert gas atomization process; high-entropy alloy powder is deposited on the surface of the high-temperature alloy substrate by adopting a high velocity oxy-fuel spraying process, and a bonding layer of the thermal barrier coating is obtained; and preparing a thermal barrier coating on the bonding layer by adopting a plasma spraying process, and carrying out vacuum heat treatment on the thermal barrier coating in advance. The high-entropy alloy bonding layer provided by the invention has better thermal stability, and can still keep strong bonding force between the ceramic layer and the bonding layer alloy after water quenching high-temperature thermal cycle service. And the transition group high-entropy alloy bonding layer is beneficial to formation of a thermal growth oxide layer, has an inhibition effect on diffusion of metal elements and coating degradation in the hydrogen-induced corrosion and high-temperature steam corrosion processes, and can prolong the high-temperature thermal shock service time of the hydrogen-doped gas turbine.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy and thermal spraying surface engineering technology, specifically relating to a method for extending the high-temperature service life of thermal barrier coatings for hydrogen-doped gas turbines. Background Technology

[0002] Against the backdrop of the global energy crisis and dual-carbon goals, gas turbines are developing towards higher flow ratios, higher thrust-to-weight ratios, and higher turbine inlet temperatures. Currently, the inlet temperature of heavy-duty gas turbines has reached 1600℃, and key blades commonly employ directionally solidified single-crystal high-temperature alloys, film cooling technology, and thermal barrier coating technology to cope with harsh high-temperature corrosion and oxidation environments. NASA was the first to use thermal barrier coating technology to improve engine thrust (for every 14-15K increase in operating temperature, total thrust increases by 1%-2%), and it can also significantly improve the lifespan of aero-turbine engines (for every 14K decrease in surface temperature, it is equivalent to doubling the lifespan of components). In recent years, my country has explicitly proposed to deeply explore hydrogen and ammonia co-firing technologies in thermal power plants. Furthermore, it has proposed a demonstration project for a new "electricity-hydrogen-electricity" model based on pure hydrogen gas turbine innovation. While ground-based hydrogen co-firing and all-hydrogen gas turbine technologies can change combustion dynamics and improve combustion efficiency, reducing carbon emissions, they also bring new challenges to gas turbines, such as hydrogen embrittlement caused by hydrogen and water vapor, and high-temperature water vapor thermal corrosion. Therefore, researching novel thermal barrier coating systems for high-reliability hydrogen-blended gas turbines is of great significance for improving the thermal protection performance of gas turbines and extending their high-temperature service life.

[0003] Although scholars both domestically and internationally have conducted some research on the binder materials and coating preparation processes of traditional thermal barrier coatings, they still fall short of meeting the application requirements of hydrogen-doped / all-hydrogen ultra-high temperature thermal barrier coatings. Therefore, in order to overcome the limitations of traditional thermal barrier coatings in the service environment, it is particularly important to develop new binder systems to improve the high-temperature service life of thermal barrier coatings. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by providing a method for extending the high-temperature service life of thermal barrier coatings in hydrogen-doped gas turbines.

[0005] The present invention adopts the following technical solution: This invention provides a method for extending the high-temperature service life of thermal barrier coatings in hydrogen-doped gas turbines, comprising the following steps: S1. Ni, Co, Cr, Fe, Al, Hf, Si and Y are melted and cast into ingots according to the proportions to obtain the master alloy; S2. The master alloy is prepared into high-entropy alloy powder by inert gas atomization process; S3. Using plasma spraying or supersonic flame spraying processes, the high-entropy alloy powder prepared in S2 is deposited onto the surface of a high-temperature alloy substrate to obtain the bonding layer of the thermal barrier coating. S4. A thermal barrier coating is prepared on the adhesive layer using plasma spraying technology, and the thermal barrier coating is pre-treated by vacuum heat treatment.

[0006] Furthermore, in step S1, the molar percentage content of each element in the master alloy is as follows: Metallic elements: Ni: 14~28%, Co: 15~29%, Cr: 14~28%, Al: 10~25%, Fe: 15~31%; Trace refractory elements: Hf: 0.09~0.15%; Rare earth elements: Y: 0.12~0.15%; and Si: 0.49~0.70%.

[0007] Furthermore, in step S1, after the proportions of Ni, Co, Cr, Fe, Al, Hf, Si, and Y are completed, the mixture is placed in a vacuum arc melting furnace to melt and cast into ingots.

[0008] Step S2 specifically involves: placing the master alloy into a gas atomizing device, and using supersonic argon gas flow to perform tight coupling atomization of the alloy liquid flow under process parameters of alloy superheat 100~200℃, holding temperature 1900~2150℃, and atomization pressure 5.5~7.0 MPa (the high-pressure inert gas jet will break the metal liquid flow, and the small droplets will condense into spherical powders) to prepare spherical metal powders. After sieving with a sieve, the powders are mixed. The particle size of the spherical metal powders is 15~53 μm, 45~75 μm, or 53~150 μm; the purity of the argon gas is 99.999%.

[0009] Furthermore, in step S3, the parameters of the supersonic flame spraying process are as follows: kerosene flow rate is 12~18 L / h, oxygen flow rate is 500~650 L / h, oxygen pressure is 1.5~2.0 MPa, nitrogen flow rate for powder feeding is 550~700 L / h, nitrogen pressure for powder feeding is 0.8~1.2 MPa, chiller pressure is 1.0~1.2 MPa, powder feeding rate is 2 r / min, and spraying distance is 250~300 mm.

[0010] Furthermore, in step S3, before depositing the adhesive layer on the surface of the high-temperature alloy substrate, a sandblasting roughening treatment is performed.

[0011] Furthermore, in step S4, the parameters of the plasma spraying process are as follows: voltage 55~70 V, current 550~650 A, argon flow rate 2000~3600 L / h, hydrogen flow rate 300~720 L / h, powder-feeding nitrogen flow rate 360~840 L / min, powder-feeding nitrogen pressure 0.3~0.5 MPa, powder feeding rate 2 r / min, and spraying distance 100~120 mm. Furthermore, the parameters for the pre-vacuum heat treatment of the thermal barrier coating are as follows: temperature 1050℃, vacuum heat treatment time 4h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0012] Furthermore, the thickness of the adhesive layer is 150~200μm, and the thickness of the thermal barrier coating is 200~350μm.

[0013] Furthermore, the material of the thermal barrier coating is yttrium-stabilized zirconium oxide (8wt.%YSZ) with a yttrium oxide weight percentage of 8%.

[0014] The beneficial effects of this invention are: (1) The present invention uses a high-entropy alloy as the bonding underlayer, which has better thermal stability and helps to maintain a strong bond between the ceramic layer and the high-entropy alloy bonding layer after water quenching and high-temperature thermal cycling, thereby indirectly inhibiting the formation and propagation of cracks in the thermal barrier coating ceramic layer.

[0015] (2) The high-entropy chemical composition design of the NiCoCrFeAlHfSiY high-entropy alloy bonding layer of the present invention (appropriate amount of Al element, refractory element Hf and rare earth element Y) not only helps to form a simple, continuous and fine-grained alumina-based thermally grown oxide layer (TGO), but also plays an important role in the diffusion of metal elements and coating degradation during hydrogen-induced corrosion and high-temperature water vapor corrosion, and can extend the high-temperature thermal shock service time of the structural materials of hydrogen-doped gas turbines. Attached Figure Description

[0016] Figure 1 These are material characterization diagrams prepared in Example 1, where a is a morphology diagram of the high-entropy alloy powder, b is a cross-sectional diagram of the high-temperature alloy substrate / binder layer / thermal barrier coating, and c is an elemental surface distribution diagram of the gas-atomized high-entropy alloy binder layer powder particles. Figure 2 This is a thermal shock service life assessment diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 1; Figure 3 This is a thermal shock service life assessment diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 2; Figure 4 This is a thermal shock service life assessment diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 3; Figure 5 This is a thermal shock service life assessment diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 4; Figure 6 This is a thermal shock service life assessment diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Comparative Example 1; Figure 7 This is a thermal shock service life assessment diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Comparative Example 2. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 This embodiment provides a method for extending the high-temperature service life of thermal barrier coatings in hydrogen-doped gas turbines, including the following steps: (1) Weigh Ni, Co, Cr, Fe, Al, Hf, Si and Y according to the ratio. The molar percentage content of each element is as follows: Ni: 20%, Co: 19%, Cr: 19%, Al: 25%, Fe: 16%, Hf: 0.15%, Y: 0.15%, Si: 0.70%.

[0019] (2) The proportioned materials are placed in a vacuum arc melting furnace and melted and cast into an ingot to obtain a master alloy rod (Ф70 mm).

[0020] (3) The master alloy rod is placed in a gas atomizing device. Under the process parameters of alloy superheat of 100℃, heat preservation temperature of 2150℃ and atomization pressure of 7.0 MPa, the alloy liquid flow is tightly coupled and atomized by supersonic argon gas flow (purity is 99.999%) (the high-pressure inert gas jet will break the metal liquid flow and the small droplets will condense into spherical powder) to prepare spherical metal powder. After sieving with a sieve, the powder is mixed to obtain spherical metal powder with a particle size of 15~53 μm.

[0021] (4) The surface of the high-temperature alloy substrate (nickel-based high-temperature alloy K465) is roughened by sandblasting. The sandblasting medium is No. 60 white corundum and the sandblasting pressure is 0.7 MPa.

[0022] (5) Using a kerosene supersonic flame spraying process, the high-entropy alloy spherical powder prepared in step (3) is deposited onto the roughened high-temperature alloy substrate surface to obtain the bonding layer of the thermal barrier coating. The thickness of the bonding layer is 200 μm. The parameters of the supersonic flame spraying process are as follows: kerosene flow rate is 14 L / h, oxygen flow rate is 550 L / h, oxygen pressure is 1.8 MPa, nitrogen flow rate for powder feeding is 600 L / h, nitrogen pressure for powder feeding is 1.0 MPa, chiller pressure is 1.2 MPa, powder feeding rate is 2 r / min, and spraying distance is 300 mm.

[0023] (6) An atmospheric plasma spraying process was used to prepare a thermal barrier coating (8wt.% YSZ ceramic functional layer) on the adhesive layer. The thickness of the thermal barrier coating was 250μm. The plasma spraying process parameters were as follows: voltage 55 V, current 600 A, argon flow rate 2800 L / h, hydrogen flow rate 300 L / h, nitrogen flow rate for powder feeding 600 L / min, nitrogen pressure for powder feeding 0.3 MPa, powder feeding rate 2 r / min, and spraying distance 120 mm.

[0024] (7) The thermal barrier coating is subjected to pre-vacuum heat treatment. The process parameters are: temperature 1050℃, vacuum heat treatment time 4h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0025] Example 2 This embodiment provides a method for extending the high-temperature service life of thermal barrier coatings in hydrogen-doped gas turbines, including the following steps: (1) Weigh Ni, Co, Cr, Fe, Al, Hf, Si and Y according to the ratio. The molar percentage content of each element is as follows: Ni: 21%, Co: 22%, Cr: 21%, Al: 12%, Fe: 23%, Hf: 0.15%, Y: 0.15%, Si: 0.70%.

[0026] (2) The proportioned materials are placed in a vacuum arc melting furnace and melted and cast into an ingot to obtain a master alloy rod (Ф70 mm).

[0027] (3) The master alloy rod is placed in a gas atomizing device. Under the process parameters of alloy superheat of 100℃, heat preservation temperature of 2150℃ and atomization pressure of 7.0 MPa, the alloy liquid flow is tightly coupled and atomized by supersonic argon gas flow (purity is 99.999%) (the high-pressure inert gas jet will break the metal liquid flow and the small droplets will condense into spherical powder) to prepare spherical metal powder. After sieving with a sieve, the powder is mixed to obtain spherical metal powder with a particle size of 15~53 μm.

[0028] (4) The surface of the high-temperature alloy substrate (nickel-based high-temperature alloy K465) is roughened by sandblasting. The sandblasting medium is No. 60 white corundum and the sandblasting pressure is 0.7 MPa.

[0029] (5) Using a kerosene supersonic flame spraying process, the high-entropy alloy spherical powder prepared in step (3) is deposited onto the roughened high-temperature alloy substrate surface to obtain the bonding layer of the thermal barrier coating. The thickness of the bonding layer is 200 μm. The parameters of the supersonic flame spraying process are as follows: kerosene flow rate is 14 L / h, oxygen flow rate is 550 L / h, oxygen pressure is 1.8 MPa, nitrogen flow rate for powder feeding is 600 L / h, nitrogen pressure for powder feeding is 1.0 MPa, chiller pressure is 1.2 MPa, powder feeding rate is 2 r / min, and spraying distance is 300 mm.

[0030] (6) An atmospheric plasma spraying process was used to prepare a thermal barrier coating (8wt.% YSZ ceramic functional layer) on the adhesive layer. The thickness of the thermal barrier coating was 250μm. The plasma spraying process parameters were as follows: voltage 55 V, current 600 A, argon flow rate 2800 L / h, hydrogen flow rate 300 L / h, nitrogen flow rate for powder feeding 600 L / min, nitrogen pressure for powder feeding 0.3 MPa, powder feeding rate 2 r / min, and spraying distance 120 mm.

[0031] (7) The thermal barrier coating is subjected to pre-vacuum heat treatment. The process parameters are: temperature 1050℃, vacuum heat treatment time 4h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0032] Example 3 This embodiment provides a method for extending the high-temperature service life of thermal barrier coatings in hydrogen-doped gas turbines, including the following steps: (1) Weigh Ni, Co, Cr, Fe, Al, Hf, Si and Y according to the ratio. The molar percentage content of each element is as follows: Ni: 20%, Co: 19%, Cr: 19%, Al: 25%, Fe: 16%, Hf: 0.15%, Y: 0.15%, Si: 0.70%.

[0033] (2) The proportioned materials are placed in a vacuum arc melting furnace and melted and cast into an ingot to obtain a master alloy rod (Ф70 mm).

[0034] (3) The master alloy rod is placed in a gas atomizing device. Under the process parameters of alloy superheat of 100℃, heat preservation temperature of 2150℃ and atomization pressure of 7.0 MPa, the alloy liquid flow is tightly coupled and atomized by supersonic argon gas flow (purity is 99.999%) (the high-pressure inert gas jet will break the metal liquid flow and the small droplets will condense into spherical powder) to prepare spherical metal powder. After sieving with a sieve, the powder is mixed to obtain spherical metal powder with a particle size of 15~53 μm.

[0035] (4) The surface of the high-temperature alloy substrate (cobalt-based high-temperature alloy Haynes188) was roughened by sandblasting. The sandblasting medium was No. 60 white corundum and the sandblasting pressure was 0.7 MPa.

[0036] (5) Using a kerosene supersonic flame spraying process, the high-entropy alloy spherical powder prepared in step (3) is deposited onto the roughened high-temperature alloy substrate surface to obtain the bonding layer of the thermal barrier coating. The thickness of the bonding layer is 200 μm. The parameters of the supersonic flame spraying process are as follows: kerosene flow rate is 14 L / h, oxygen flow rate is 550 L / h, oxygen pressure is 1.8 MPa, nitrogen flow rate for powder feeding is 600 L / h, nitrogen pressure for powder feeding is 1.0 MPa, chiller pressure is 1.2 MPa, powder feeding rate is 2 r / min, and spraying distance is 300 mm.

[0037] (6) An atmospheric plasma spraying process was used to prepare a thermal barrier coating (8wt.% YSZ ceramic functional layer) on the adhesive layer. The thickness of the thermal barrier coating was 250μm. The plasma spraying process parameters were as follows: voltage 55 V, current 600 A, argon flow rate 2800 L / h, hydrogen flow rate 300 L / h, nitrogen flow rate for powder feeding 600 L / min, nitrogen pressure for powder feeding 0.3 MPa, powder feeding rate 2 r / min, and spraying distance 120 mm.

[0038] (7) The thermal barrier coating is subjected to pre-vacuum heat treatment. The process parameters are: temperature 1050℃, vacuum heat treatment time 4h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0039] Example 4 This embodiment provides a method for extending the high-temperature service life of thermal barrier coatings in hydrogen-doped gas turbines, including the following steps: (1) Weigh Ni, Co, Cr, Fe, Al, Hf, Si and Y according to the ratio. The molar percentage content of each element is as follows: Ni: 21%, Co: 22%, Cr: 21%, Al: 12%, Fe: 23%, Hf: 0.15%, Y: 0.15%, Si: 0.70%.

[0040] (2) The proportioned materials are placed in a vacuum arc melting furnace and melted and cast into an ingot to obtain a master alloy rod (Ф70 mm).

[0041] (3) The master alloy rod is placed in a gas atomizing device. Under the process parameters of alloy superheat of 100℃, heat preservation temperature of 2150℃ and atomization pressure of 7.0 MPa, the alloy liquid flow is tightly coupled and atomized by supersonic argon gas flow (purity is 99.999%) (the high-pressure inert gas jet will break the metal liquid flow and the small droplets will condense into spherical powder) to prepare spherical metal powder. After sieving with a sieve, the powder is mixed to obtain spherical metal powder with a particle size of 15~53 μm.

[0042] (4) The surface of the high-temperature alloy substrate (cobalt-based high-temperature alloy Haynes188) was roughened by sandblasting. The sandblasting medium was No. 60 white corundum and the sandblasting pressure was 0.7 MPa.

[0043] (5) Using a kerosene supersonic flame spraying process, the high-entropy alloy spherical powder prepared in step (3) is deposited onto the roughened high-temperature alloy substrate surface to obtain a thermal barrier coating adhesive layer with a thickness of 200 μm. The parameters of the supersonic flame spraying process are as follows: kerosene flow rate is 14 L / h, oxygen flow rate is 550 L / h, oxygen pressure is 1.8 MPa, nitrogen flow rate for powder feeding is 600 L / h, nitrogen pressure for powder feeding is 1.0 MPa, chiller pressure is 1.2 MPa, powder feeding rate is 2 r / min, and spraying distance is 300 mm.

[0044] (6) An atmospheric plasma spraying process was used to prepare a thermal barrier coating (8wt.% YSZ ceramic functional layer) on the adhesive layer. The thickness of the thermal barrier coating was 250μm. The plasma spraying process parameters were as follows: voltage 55 V, current 600 A, argon flow rate 2800 L / h, hydrogen flow rate 300 L / h, nitrogen flow rate for powder feeding 600 L / min, nitrogen pressure for powder feeding 0.3 MPa, powder feeding rate 2 r / min, and spraying distance 120 mm.

[0045] (7) The thermal barrier coating is subjected to pre-vacuum heat treatment. The process parameters are: temperature 1050℃, vacuum heat treatment time 4h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0046] Comparative Example 1 Comparative Example 1 includes the following steps: (1) The surface of the high-temperature alloy substrate (cobalt-based high-temperature alloy Haynes188) was roughened by sandblasting. The sandblasting medium was No. 60 white corundum and the sandblasting pressure was 0.7 MPa.

[0047] (2) A bonding layer for a commercial thermal barrier coating of NiCoCrAlHfYSi (Amdry386) powder was prepared using a kerosene supersonic flame spraying process. The thickness of the bonding layer was 200 μm. The parameters of the supersonic flame spraying process were as follows: kerosene flow rate of 14 L / h, oxygen flow rate of 550 L / h, oxygen pressure of 1.8 MPa, nitrogen flow rate for powder feeding of 600 L / h, nitrogen pressure for powder feeding of 1.0 MPa, chiller pressure of 1.2 MPa, powder feeding rate of 2 r / min, and spraying distance of 300 mm.

[0048] (3) An atmospheric plasma spraying process was used to prepare a thermal barrier coating (8wt.% YSZ ceramic functional layer) on the adhesive layer. The thickness of the thermal barrier coating was 250 μm. The plasma spraying process parameters were as follows: voltage 55 V, current 600 A, argon flow rate 2800 L / h, hydrogen flow rate 300 L / h, nitrogen flow rate for powder feeding 360~840 L / min, nitrogen pressure for powder feeding 0.3 MPa, powder feeding rate 2 r / min, and spraying distance 120 mm.

[0049] (4) The thermal barrier coating is subjected to pre-vacuum heat treatment. The process parameters are: temperature 1050 ℃, vacuum heat treatment time 4 h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0050] Comparative Example 2 Comparative Example 2 includes the following steps: (1) The surface of the high-temperature alloy substrate (cobalt-based high-temperature alloy K465) was roughened by sandblasting. The sandblasting medium was No. 60 white corundum and the sandblasting pressure was 0.7 MPa.

[0051] (2) A bonding layer for a commercial thermal barrier coating of NiCoCrAlHfYSi (Amdry386) powder was prepared using a kerosene supersonic flame spraying process. The thickness of the bonding layer was 200 μm. The parameters of the supersonic flame spraying process were as follows: kerosene flow rate of 14 L / h, oxygen flow rate of 550 L / h, oxygen pressure of 1.8 MPa, nitrogen flow rate for powder feeding of 600 L / h, nitrogen pressure for powder feeding of 1.0 MPa, chiller pressure of 1.2 MPa, powder feeding rate of 2 r / min, and spraying distance of 300 mm.

[0052] (3) An atmospheric plasma spraying process was used to prepare a thermal barrier coating (8wt.% YSZ ceramic functional layer) on the adhesive layer. The thickness of the thermal barrier coating was 250 μm. The plasma spraying process parameters were as follows: voltage 55 V, current 600 A, argon flow rate 2800 L / h, hydrogen flow rate 300 L / h, nitrogen flow rate for powder feeding 600 L / min, nitrogen pressure for powder feeding 0.3 MPa, powder feeding rate 2 r / min, and spraying distance 120 mm.

[0053] (4) The thermal barrier coating is subjected to pre-vacuum heat treatment. The process parameters are: temperature 1050 ℃, vacuum heat treatment time 4 h, and vacuum degree 7×10 during the heating stage. -3 Pa, vacuum degree during the isothermal stage is 3×10 -3 Pa.

[0054] Effect test Figure 1 (a) is a morphology diagram of high-entropy alloy powder, indicating that the particle size distribution of the prepared high-entropy alloy powder is suitable for the bonding underlayer of thermal barrier coating prepared by supersonic flame spraying. Figure 1 (b) is a cross-sectional view of the high-temperature alloy substrate / adhesive layer / thermal barrier coating, showing that a thermal barrier coating system has been successfully prepared on the substrate metal surface. Figure 1 (c) is the elemental distribution diagram of the powder particles of the gas-atomized high-entropy alloy binder layer, which shows that a high-entropy alloy with relatively uniform distribution of Fe, Cr, Co, Ni and Al metal elements has been formed.

[0055] Figure 2 This is a thermal shock service life evaluation diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 1. The high-temperature alloy substrate is K465, and the thermal shock process parameters are: 1100 ℃, holding time 10 hours, and water quenching 25 ℃. Figure 2 It can be seen that after 42 high-temperature thermal shock cycles, the thermal barrier coating suffered extensive peeling, with one-third of the coating peeling off, resulting in complete coating failure.

[0056] Figure 3 This is a thermal shock service life evaluation diagram for the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 2. The high-temperature alloy substrate is K465, and the thermal shock process parameters are: 1100 ℃, holding time 10 hours, and water quenching 25 ℃. Figure 3 It can be seen that after 27 cycles of high-temperature thermal shock service, the thermal barrier coating bulged from the edge and detached from the high-temperature alloy substrate, and the coating completely failed.

[0057] Figure 4 This is a thermal shock service life evaluation diagram for the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 3. The high-temperature alloy substrate is HAYNES188, and the thermal shock process parameters are: 1050 ℃, holding time 10 hours, and water quenching 25 ℃. Figure 4 It can be seen that after 72 cycles of high-temperature thermal shock service, the thermal barrier coating cracks propagated and eventually peeled off, with a peeling area of ​​80 mm. 2 The amount of peeling reached 1 / 3, and the coating completely failed.

[0058] Figure 5 This is a thermal shock service life evaluation diagram for the high-temperature alloy substrate / binder / thermal barrier coating prepared in Example 4. The high-temperature alloy substrate is HAYNES188, and the thermal shock process parameters are: 1050 ℃, holding time 10 hours, and water quenching at 25 ℃. Figure 5 It can be seen that after 64 cycles of high-temperature thermal shock service, the thermal barrier coating suffered extensive peeling, with a peeling area of ​​70 mm. 2 The coating has completely failed. Figure 6 This is a thermal shock service life evaluation diagram of the high-temperature alloy substrate / binder / thermal barrier coating prepared in Comparative Example 1. The high-temperature alloy substrate is HAYNES188, and the thermal shock process parameters are: 1050 ℃, holding time 10 hours, and water quenching 25 ℃. Figure 6 It can be seen that after 30 high-temperature thermal shocks, the thermal barrier coating suffered large-area peeling, with the peeling area reaching 2 / 5 of the total area, and the coating completely failed.

[0059] Figure 7 This is a thermal shock service life evaluation diagram for the high-temperature alloy substrate / binder / thermal barrier coating prepared in Comparative Example 2. The high-temperature alloy substrate is K465, and the thermal shock process parameters are: 1100 ℃, holding time 10 hours, and water quenching 25 ℃. Figure 6 It can be seen that after 20 high-temperature thermal shocks, the thermal barrier coating suffered large-scale peeling, with the peeling area reaching 2 / 5 of the total area, and the coating completely failed.

[0060] As can be seen from the above, compared with the comparative examples, Examples 1-4 of this application significantly improve the thermal shock service life of the thermal barrier coating. Furthermore, when preparing the thermal barrier coating using the same high-temperature alloy as the substrate, the thermal shock service life of the thermal barrier coating in Example 3 is greater than that in Example 4, and the thermal shock service life of the thermal barrier coating in Example 1 is greater than that in Example 2. This is because the Al element in the binder layer can be used to ensure the oxidation resistance of the thermal barrier coating. A higher Al content can form a denser and more adhesive alumina protective film at high temperatures, effectively blocking oxygen diffusion inward, delaying the oxidation of the substrate / binder interface and the growth of thermally grown oxides, and indirectly improving the high-temperature service life of the thermal barrier coating.

[0061] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method of extending the high temperature service life of a hydrogen-doped gas turbine thermal barrier coating, characterized by, The method comprises the following steps: S1, smelting and ingot casting of Ni, Co, Cr, Fe, Al, Hf, Si and Y according to the proportion to obtain a master alloy; S2, preparing the master alloy into high-entropy alloy powder by inert gas atomization process; S3, depositing the high-entropy alloy powder prepared in S2 to the surface of a high-temperature alloy substrate by plasma spraying or high-velocity oxygen fuel spraying process to obtain a bonding layer of thermal barrier coating; S4, preparing the thermal barrier coating on the bonding layer by plasma spraying process, and pre-vacuum heat treating the thermal barrier coating.

2. The method of claim 1, wherein the molar percentage content of each element in the master alloy in the step S1 is: Ni: 14-28%, Co: 15-29%, Cr: 14-28%, Al: 10-25%, Fe: 15-31%, Hf: 0.09-0.15%, Y: 0.12-0.15%, and Si: 0.49-0.70%.

3. The method of claim 1, wherein the master alloy is placed into a vacuum arc smelting furnace for smelting and ingot casting after the proportioning of Ni, Co, Cr, Fe, Al, Hf, Si and Y is completed.

4. The method of claim 1, wherein the step S2 is specifically: The master alloy is placed into a gas atomization device, and the alloy liquid stream is tightly coupled and atomized by a supersonic argon gas stream under the process parameters of an alloy superheat of 100-200 DEG C, a holding temperature of 1900-2150 DEG C, and an atomization pressure of 5.5-7.0 MPa to prepare spherical metal powder.

5. The method of claim 1, wherein the parameters of the high-velocity oxygen fuel spraying process in the step S3 are: The kerosene flow rate is 12-18 L / h, the oxygen flow rate is 500-650 L / h, the oxygen pressure is 1.5-2.0 MPa, the powder feeding nitrogen flow rate is 550-700 L / h, the powder feeding nitrogen pressure is 0.8-1.2 MPa, the cold water machine pressure is 1.0-1.2 MPa, the powder feeding rate is 2r / min, and the spraying distance is 250-300 mm.

6. The method of claim 1, wherein the high-temperature alloy substrate surface is subjected to sand blasting roughening treatment before the bonding layer is deposited thereon in the step S3.

7. The method of claim 1, wherein the parameters of the plasma spraying process in the step S4 are: ​ ​ ​ ​ ​ ​ The voltage is 55-70 V, the current is 550-650 A, the argon flow rate is 2000-3600 L / h, the hydrogen flow rate is 300-720 L / h, the powder feeding nitrogen flow rate is 360-840 L / min, the powder feeding nitrogen pressure is 0.3-0.5 MPa, the powder feeding rate is 2 r / min, and the spraying distance is 100-120 mm.

8. The method of claim 1, wherein the method further comprises, The parameters of the pre-vacuum heat treatment of the thermal barrier coating are: The temperature is 1050℃, the vacuum heat treatment time is 4h, the vacuum degree in the heating stage is 7x10 -3 Pa, and the vacuum degree in the constant temperature stage is 3x10 -3 Pa.

9. The method of claim 1, wherein the method further comprises, The thickness of the bonding layer is 150-200 μm, and the thickness of the thermal barrier coating is 200-350 μm.

10. The method of claim 1, wherein the material of the thermal barrier coating is yttria-stabilized zirconia with 8% yttria by weight. ​

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