A method for preparing a corrosion-resistant thermal barrier coating and its application

Abstract

The present invention discloses a method for preparing a corrosion-resistant thermal barrier coating and its application. The preparation method comprises the following steps: (1) respectively weighing ceramic powders required for preparing the coating: ZrO2, Dy2O3 and TaO5; (2) providing a material substrate, and subjecting the substrate to grinding, polishing, sandblasting and ultrasonic cleaning; (3) preparing a NiCoCrAlY bonding layer on the surface of the substrate by using supersonic plasma spraying technology; and (4) depositing ZrO2-Dy3TaO7 powder on the surface of the bonding layer by using atmospheric plasma spray-physical vapor deposition technology, thereby obtaining a single ceramic layer coating system. The corrosion-resistant thermal barrier coating prepared according to the present invention has good density, can remain dense and continuous after serving at a high temperature of 1200°C for 1000 hours, and does not show any ceramic layer shedding or peeling phenomenon, and has good application prospects.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a corrosion-resistant thermal barrier coating, and belongs to the technical field of corrosion-resistant thermal barrier coatings. Background Art

[0002] The ISA furnace lance tubes are required to operate in high-temperature molten copper for extended periods of time. Therefore, the bottom portion of the lance, which inserts into the molten copper, places stringent requirements on heat resistance and corrosion resistance. However, existing ISA furnace lance tubes made of 316 stainless steel are insufficient for long-term service in high-temperature molten copper. To address this, a thermal barrier and corrosion-resistant coating is sprayed onto the ISA furnace lance base to mitigate the risk of rapid failure of the lance tube due to direct contact with the high-temperature molten copper, thereby extending its service life in high-temperature copper molten liquid. The coating consists of a bonding layer and a ceramic layer. The bonding layer, located between the ceramic layer and the base, effectively minimizes the thermal expansion mismatch between the ceramic layer and the base, reduces thermal stress between the coating layers, and protects the base from oxidation. The ceramic layer acts as a thermal insulator, reducing heat transfer to the base.

[0003] Studies have found that reducing the thermal conductivity of a coating can improve its high-temperature resistance. Therefore, researchers are looking to improve the coating's performance by adjusting the coating material itself and the spraying method. Some new thermal barrier coating materials, such as advanced YSZ coatings, have higher thermal conductivity than ZrO2-Dy3TaO7 at high temperatures. Furthermore, oxide coatings with perovskite-like structures have a much lower thermal expansion coefficient than ZrO2-Dy3TaO7 and exhibit severe cracking defects. Spraying technology is also a key factor influencing the performance of coating materials. Physical and chemical vapor deposition (PVD) is often considered a key factor due to its low cost, ease of operation, and excellent high-temperature resistance. However, PVD requires complex equipment and is prone to generating large particles at high temperatures, severely impacting coating quality. Chemical vapor deposition (CVD) has a low deposition rate, resulting in coatings with lower high-temperature resistance than PVD and prone to failure at high temperatures.

[0004] In response to the above-mentioned problems, the present invention proposes a method of preparing a high-temperature resistant coating by using supersonic plasma spraying (HVOF) to prepare a bonding layer and atmospheric plasma spray-physical vapor deposition technology (PS-PVD) to prepare a ceramic layer. The two spraying methods are combined to prepare a corrosion-resistant and excellent performance coating. Summary of the Invention

[0005] One objective of the present invention is to provide a method for preparing a corrosion-resistant thermal barrier coating. By doping tantalate with Zr and Dy, lattice defects are introduced, reducing the material's thermal conductivity and increasing its coefficient of thermal expansion. The ZrO2-Dy3TaO7 rare earth coating material exhibits low thermal conductivity, a high coefficient of thermal expansion, and excellent impact and corrosion resistance. This addresses the challenges of existing corrosion-resistant thermal barrier coatings, such as insufficient stability at high temperatures, prone to phase transitions, significant internal stress, reduced toughness, and susceptibility to peeling and failure.

[0006] The preparation of the corrosion-resistant thermal barrier coating of the present invention specifically includes the following steps:

[0007] (1) Weigh ZrO2, Dy2O3, and TaO5 powders, mix them by ball milling, and then dry them.

[0008] (2) The mixture obtained in step (1) is sintered, followed by conventional granulation, and finally sieved to obtain ZrO2-Dy3TaO7 ceramic powder.

[0009] (3) Polishing, sandblasting and ultrasonic cleaning of the substrate surface.

[0010] (4) Using supersonic plasma spraying technology, spray NiCoCrAlY on the substrate obtained in step (3) to form a bonding layer.

[0011] (5) The ZrO2-Dy3TaO7 ceramic powder obtained in step (2) is deposited on the surface of the bonding layer obtained in step (4) by atmospheric plasma spraying technology to form a ZrO2-Dy3TaO7 ceramic layer.

[0012] Preferably, the mass ratio of ZrO2, Dy2O3, and TaO5 powders in step (1) is: 12.69-16.34: 55.23-60.56: 40.58-46.45, and the purity of each powder is above 99%; the ball milling medium is anhydrous ethanol or deionized water, the ball milling mixing time is 10-20h, the rotation speed is 250-280r / min; and the drying condition is baking at 60℃-70℃ for more than 1.5h.

[0013] Preferably, in step (2), sintering is carried out in an atmosphere at 1450-1550° C. for 15-25 hours; and after sieving, the particle size of the ZrO 2 -Dy 3 TaO 7 ceramic powder is between 40 and 100 μm.

[0014] Preferably, the substrate material in step (3) is 316 stainless steel; the polishing treatment uses a polishing machine or sandpaper to polish impurities and oxide scale on the surface of the substrate; sandblasting uses 10-50 mesh particles at a wind pressure of 0.15-0.55 MPa, the sandblasting distance is 110-130 mm, the sandblasting angle is 50-60°, and the sandblasting time is 40-60 s; ultrasonic cleaning treatment uses any one of alcohol, kerosene or acetone solutions to ultrasonically clean the substrate.

[0015] Preferably, in step (4), the spraying distance is 200-400 mm, the spray gun moving speed is 450-550 mm / s, the spraying voltage is 120-130 V, the spraying current is 350-400 A, the spraying pressure is 0.65-0.75 MPa, the powder feeding rate is 30-50 g / min, the spraying gas source is Ar gas and compressed air, the compressed air flow rate is 10-20 SLPM, the auxiliary gas argon flow rate is 50-100 SLPM, the thickness of the NiCoCrAlY bonding layer is 150-250 μm, and the composition of NiCoCrAlY is a substance including the following mass percentages: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5t% Y.

[0016] Preferably, when using PS-PVD to spray the ZrO2-Dy3TaO7 ceramic layer on the bonding layer in step (5), the vacuum in the chamber is evacuated to 0.6-0.8 mbar, and then argon is backfilled to 30-35 mbar and the spray gun is ignited, and then the vacuum is evacuated to 1.8-2.0 mbar, the preheating temperature is 900-950°C, and the ceramic layer is started to be sprayed. The parameters for preparing the ceramic layer are: spraying distance 100-180 mm, spray gun movement speed 300-500 mm / s, spraying voltage 60-100 V, spraying current 450-600 A, powder feeding rate 30-40 g / min, powder feeding argon flow rate 60-120 SLPM, hydrogen flow rate 10-20 SLPM, and the thickness of the ZrO2-Dy3TaO7 ceramic layer is 150-240 μm.

[0017] Preferably, the prepared ZrO2-Dy3TaO7 high temperature corrosion resistant coating has the following molar contents of each element: Zr 20-30%, Dy 20-50%, Ta 10-20%, the porosity of the high temperature corrosion resistant coating is 8%-25%, and the temperature resistance can reach 1200°C.

[0018] Another object of the present invention is to provide an application of a corrosion-resistant thermal barrier coating, wherein the corrosion-resistant thermal barrier coating of the present invention is applied to the surface of a spray gun used in an Isa furnace.

[0019] Principle of the invention: A series of chemical reactions occur during the sintering of ZrO2, Dy2O3, and TaO5 powders to produce ZrO2-Dy3TaO7. The presence of rare earth elements Ta and Dy enables the prepared rare earth dysprosium tannate ceramic material to have higher operating temperatures, more significant thermal insulation and protection properties, and longer service life compared to traditional yttria-stabilized zirconia coatings.

[0020] ZrO2-Dy3TaO7 thermal barrier coatings are prepared using atmospheric plasma spraying-physical vapor deposition technology. The sprayed material powder is vaporized using a plasma spray gun, then rapidly cooled and deposited on the pretreated bond layer. The resulting ceramic coating exhibits a strong bond to the bond layer, and the ceramic particles are uniformly, continuously, and densely distributed on the bond layer surface. During heat transfer, the disordered atomic distribution creates a large number of defects, which reduces the mean free path of phonons and, consequently, thermal conductivity.

[0021] Beneficial effects of the present invention

[0022] (1) Using TaO5 as the system to dope ZrO2 and Dy2O3 to obtain ZrO2-Dy3TaO7 high temperature resistant coating and improve the corrosion resistance of copper liquid

[0023] (2) A NiCoCrAlY ceramic bonding layer was prepared by supersonic plasma spraying, and a ZrO2-Dy3TaO7 corrosion-resistant thermal barrier coating was prepared by atmospheric plasma spraying-physical vapor deposition technology. The coating has the characteristics of continuous density, a porosity of 8%-25%, and the presence of microcracks, which relieves the internal stress of the coating and effectively reduces the thermal conductivity of the coating. No peeling or shedding occurs after working at a high temperature of 1200°C for 1000 hours.

[0024] (3) The corrosion-resistant thermal barrier coating can be applied to the surface of the spray gun used in the Isa furnace to achieve a longer working life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a macroscopic image of the surface of the ZrO2-Dy3TaO7 thermal barrier coating obtained by PS-PVD spraying in Example 1;

[0026] Figure 2 This is a microscopic image of the cross section of the ZrO2-Dy3TaO7 thermal barrier coating obtained by PS-PVD spraying in Example 1;

[0027] Figure 3 This is a cross-sectional micrograph of the ZrO2-Dy3TaO7 thermal barrier coating obtained by PS-PVD spraying in Example 1 after 1000h of high-temperature thermal fatigue test at 1200℃;

[0028] Figure 4This is a microscopic image of the cross-sectional morphology of the ZrO2-Dy3TaO7 thermal barrier coating obtained by PS-PVD spraying in Example 1 after being polished in a molten copper environment at 1200°C for 1000 hours. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0030] Example 1

[0031] A preparation method of a corrosion-resistant thermal barrier coating, the specific preparation steps are as follows

[0032] (1) Weigh 15.32 g of ZrO2, 58.54 g of Dy2O3, and 42.65 g of Ta2O5 with a purity of 99% (percentage by mass) and mix them. Use deionized water as a medium and wet ball mill to mix them for 18 h. Set the speed to 260 r / min. Place the mixed powder obtained by ball milling in a temperature of 60°C for more than 1.5 h to obtain a mixed powder.

[0033] (2) The mixed powder obtained in step (1) was sintered in the atmosphere at 1500° C. for 18 h, and then granulated by a conventional method. After sieving, ZrO2-Dy3TaO7 ceramic powder with a particle size of 40-100 μm was obtained.

[0034] (3) The surface of the 316 stainless steel substrate was polished with sandpaper, and then the substrate was ultrasonically cleaned in alcohol for 8 minutes. Then, 30-mesh white corundum sand was selected and sandblasted for 50 seconds at a wind pressure of 0.3 MPa using a sandblasting machine to roughen the ultrasonically cleaned substrate surface. The sandblasting distance was 120 mm and the sandblasting angle was 55°. The sandblasted substrate was then ultrasonically cleaned in alcohol for 15 minutes to remove impurities, oil stains and sand particles remaining on the substrate surface.

[0035] (4) A NiCoCrAlY bonding layer was prepared on the surface of the 316 stainless steel obtained in step (3) using supersonic plasma spraying technology. The composition of NiCoCrAlY was the following substances in percentage by mass: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y. The spraying distance was 280 mm, the spray gun movement speed was 500 mm / s, the spraying voltage was 120 V, the spraying current was 350 A, the spraying pressure was 0.7 MPa, the powder feeding rate was 40 g / min, the spraying gas source was Ar gas and compressed air, the compressed air flow rate was 15 SLPM, the auxiliary gas argon flow rate was 80 SLPM, and the thickness of the NiCoCrAlY bonding layer was 200 μm. 316 stainless steel sprayed with a NiCoCrAlY bonding layer was obtained.

[0036] (5) The ZrO2-Dy3TaO7 ceramic powder obtained in step (2) is deposited on the surface of the 316 stainless steel sprayed with the NiCoCrAlY bonding layer obtained in step (4) by atmospheric plasma spraying technology to form a ZrO2-Dy3TaO7 ceramic layer. The vacuum in the chamber is evacuated to 0.6 mbar, and then argon is backfilled to 30 mbar and the spray gun is ignited. The vacuum is then evacuated to 1.8 mbar, the preheating temperature is 900°C, and spraying is carried out. The parameters in the ceramic layer preparation process are: spraying distance 130 mm, spray gun movement speed 400 mm / s, spraying voltage 70 V, spraying current 520 A, powder feeding rate 30 g / min, powder feeding argon flow rate 100 SLPM, hydrogen flow rate 15 SLPM, and finally 316 stainless steel coated with a ZrO2-Dy3TaO7 ceramic layer is obtained, and the ceramic layer thickness is 240 μm.

[0037] Macroscopic image of 316 stainless steel coated with ZrO2-Dy3TaO7 ceramic layer Figure 1 As shown; the microstructure of the cross section of the ZrO2-Dy3TaO7 thermal barrier coating is as follows Figure 2 As shown, from Figure 1 It can be seen that the surface of the ceramic layer is well crystallized, and the grain size distribution is uniform and dense; Figure 2 A small amount of pores and cracks were observed in both the bonding layer and the ceramic layer of the coating, indicating that no large stress and pressure were generated during the sintering process, and the density was found to be as high as 98.8%.

[0038] After 316 stainless steel coated with ZrO2-Dy3TaO7 ceramic layer was subjected to high temperature thermal fatigue test at 1200℃ for 1000h, the microstructure of the coating cross section was as follows: Figure 3 As shown in the figure, it can be seen that the bonding layer completely connects the base material and the ceramic layer. During the high-temperature service process, the coating material undergoes phase change and stress concentration occurs, resulting in some more crack defects in the bonding layer. However, after serving at a high temperature of 1200°C for 1000 hours, there is no coating peeling phenomenon, which shows that the layer prepared by the above method has good thermal insulation properties.

[0039] The 316 stainless steel coated with ZrO2-Dy3TaO7 ceramic layer was placed in a molten copper environment at 1200℃ for 1000h and then polished. The microstructure of the coating cross section is as follows: Figure 4As shown in the figure, it can be seen that after long-term service in high-temperature copper liquid, obvious hole defects appeared in the ceramic layer, but the bonding layer was not significantly affected by the high-temperature copper liquid, and no obvious defects appeared in the base material, indicating that the coating can effectively hinder the corrosion of high-temperature copper liquid. Overall, only the surface ceramic layer was affected by the corrosion of the high-temperature copper liquid, and some holes appeared, but the overall structure of the coating was still intact and coherent, indicating that the coating prepared by the above method can serve in molten copper liquid at 1200℃ for 1000h without affecting the base material.

[0040] Example 2

[0041] A preparation method of a corrosion-resistant thermal barrier coating, the specific preparation steps are as follows

[0042] (1) Weigh 12.69 g of ZrO2, 55.23 g of Dy2O3, and 40.58 g of Ta2O5 with a purity of 99% (percentage by mass) and mix them. Use anhydrous ethanol as a medium to wet ball mill the mixture for 10 h at a speed of 280 r / min. The mixed powder obtained by ball milling is baked at 60°C for more than 1.5 h to obtain a mixed powder.

[0043] (2) The mixed powder obtained in step (1) was sintered in the atmosphere at 1550° C. for 15 h, and then granulated by a conventional method. After sieving, ZrO2-Dy3TaO7 ceramic powder with a particle size of 40-100 μm was obtained.

[0044] (3) The surface of the 316 stainless steel substrate was polished with sandpaper, and then the substrate was ultrasonically cleaned in kerosene for 8 minutes. Then, 50-mesh white corundum sand was selected and sandblasted for 40 seconds at a wind pressure of 0.55 MPa using a sandblasting machine to roughen the ultrasonically cleaned substrate surface. The sandblasting distance was 130 mm and the sandblasting angle was 50°. The sandblasted substrate was then ultrasonically cleaned in kerosene for 20 minutes to remove impurities, oil stains and sand particles remaining on the substrate surface.

[0045] (4) A NiCoCrAlY bonding layer was prepared on the surface of 316 stainless steel using supersonic plasma spraying technology. The composition of NiCoCrAlY was the following substances in mass percentage: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y. The spraying distance was 400 mm, the spray gun movement speed was 550 mm / s, the spraying voltage was 130 V, the spraying current was 400 A, the spraying pressure was 0.75 MPa, the powder feeding rate was 50 g / min, the spraying gas source was Ar gas and compressed air, the compressed air flow rate was 20 SLPM, the auxiliary gas argon flow rate was 100 SLPM, and the thickness of the NiCoCrAlY bonding layer was 250 μm. 316 stainless steel sprayed with a NiCoCrAlY bonding layer was obtained.

[0046] (5) The ZrO2-Dy3TaO7 ceramic powder obtained in step (2) was deposited on the surface of the 316 stainless steel sprayed with the NiCoCrAlY bonding layer obtained in step (4) by atmospheric plasma spraying technology to form a ZrO2-Dy3TaO7 ceramic layer. The vacuum in the chamber was evacuated to 0.6 mbar, then backfilled with argon gas to 30 mbar and the spray gun was ignited. The vacuum was then evacuated to 1.8 mbar, the preheating temperature was 900°C, and spraying began. The parameters in the ceramic layer preparation process were: spraying distance 180 mm, spray gun movement speed 500 mm / s, spraying voltage 100 V, spraying current 600 A, powder feeding rate 40 g / min, powder feeding argon flow rate 120 SLPM, hydrogen flow rate 20 SLPM, and finally the thickness of the ZrO2-Dy3TaO7 ceramic layer was 150 μm.

[0047] Example 3

[0048] A preparation method of a corrosion-resistant thermal barrier coating, the specific preparation steps are as follows

[0049] (1) Weigh 16.34 g of ZrO2, 60.56 g of Dy2O3, and 46.45 g of Ta2O5 with a purity of 99% (percentage by mass), mix them, and use anhydrous ethanol as a medium to wet ball mill for 20 h. Set the speed to 250 r / min, and bake the mixed powder obtained by ball milling at 70°C for more than 1.5 h to obtain a mixed powder.

[0050] (2) The mixed powder obtained in step (1) was sintered in the atmosphere at 1450° C. for 25 h, and then granulated by a conventional method. After sieving, ZrO2-Dy3TaO7 ceramic powder with a particle size of 40-100 μm was obtained.

[0051] (3) The surface of the 316 stainless steel substrate was polished with sandpaper, and then the substrate was ultrasonically cleaned in acetone for 8 minutes. Then, 10-mesh white corundum sand was selected and sandblasted for 60 seconds at a wind pressure of 0.15 MPa using a sandblasting machine. The sandblasting distance was 110 mm and the sandblasting angle was 60°. The sandblasted substrate was then ultrasonically cleaned in acetone for 10 minutes to remove impurities, oil stains and sand particles remaining on the substrate surface.

[0052] (4) A NiCoCrAlY bonding layer was prepared on the surface of 316 stainless steel using supersonic plasma spraying technology. The composition of NiCoCrAlY was the following substances in mass percentage: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y. The spraying distance was 200 mm, the spray gun movement speed was 450 mm / s, the spraying voltage was 125 V, the spraying current was 350 A, the spraying pressure was 0.65 MPa, the powder feeding rate was 30 g / min, the spraying gas source was Ar gas and compressed air, the compressed air flow rate was 10 SLPM, the auxiliary gas argon flow rate was 50 SLPM, and the thickness of the NiCoCrAlY bonding layer was 150 μm. 316 stainless steel sprayed with a NiCoCrAlY bonding layer was obtained.

[0053] (5) The ZrO2-Dy3TaO7 ceramic powder obtained in step (2) is deposited on the surface of the 316 stainless steel sprayed with the NiCoCrAlY bonding layer obtained in step (4) by atmospheric plasma spraying technology to form a ZrO2-Dy3TaO7 ceramic layer. The vacuum in the chamber is evacuated to 0.8 mbar, and then argon is backfilled to 35 mbar and the spray gun is ignited. The vacuum is then evacuated to 2.0 mbar, the preheating temperature is 950°C, and the ceramic layer is sprayed. The parameters in the ceramic layer preparation process are: spraying distance 100 mm, spray gun movement speed 300 mm / s, spraying voltage 60 V, spraying current 450 A, powder feeding rate 35 g / min, powder feeding argon flow rate 60 SLPM, hydrogen flow rate 10 SLPM, and finally the thickness of the ZrO2-Dy3TaO7 ceramic layer obtained is 200 μm.

[0054] The 316 steel-based materials sprayed with the corrosion-resistant thermal barrier coatings prepared in Examples 1 to 3 were tested. The molar contents of Zr, Dy, and Ta in the corrosion-resistant thermal barrier coatings in each example are shown in Table 1.

[0055] Table 1 Molar contents of Zr, Dy and Ta in the corrosion-resistant thermal barrier coatings in Examples 1 to 3

[0056] Zr(％) Dy(%) Ta(%) Example 1 27.35 37.52 10.59 Example 2 22.66 35.40 10.09 Example 3 29.17 38.82 11.55

[0057] Comparative Example 1

[0058] (1) Weigh 13.48 g of 99% (mass percent) TiO2, 52.56 g of Dy2O3, and 46.26 g of Ta2O5, mix them, and use a wet ball mill with deionized water as the medium for 15 h at a speed of 250 r / min. The mixed powder obtained by ball milling is baked at 70°C for more than 2.5 h to obtain a mixed powder.

[0059] (2) The mixed powder obtained in step (1) was sintered in the atmosphere at 1450° C. for 16 h, and then granulated by a conventional method. After sieving, a TiO2-Dy3TaO7 spray powder with a particle size of 40-90 μm was obtained.

[0060] (3) Use 200#, 400#, 800#, and 2000# sandpaper to polish the surface of the 316 stainless steel substrate in sequence, then select 35-mesh white corundum sand, and use a sandblasting machine to roughen the ultrasonically cleaned substrate surface at a wind pressure of 0.35 MPa for 60 seconds. Then, the sandblasted substrate is ultrasonically cleaned in alcohol for 12 minutes to remove impurities, oil stains, and sand particles remaining on the substrate surface.

[0061] (4) A NiCoCrAlY bonding layer was prepared on the surface of the 316 stainless steel obtained in step (3) using supersonic plasma spraying technology. The composition of NiCoCrAlY was the following substances in percentage by mass: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y. The spraying distance was 300 mm, the spray gun movement speed was 480 mm / s, the spraying voltage was 130 V, the spraying current was 380 A, the spraying pressure was 0.65 MPa, the powder feeding rate was 40 g / min, the spraying gas source was Ar gas and compressed air, the compressed air flow rate was 18 SLPM, the auxiliary gas argon flow rate was 70 SLPM, and the thickness of the NiCoCrAlY bonding layer was 220 μm. 316 stainless steel sprayed with a NiCoCrAlY bonding layer was obtained.

[0062] (5) The TiO2-Dy3TaO7 spray powder obtained in step (2) is deposited on the surface of the 316 stainless steel of the NiCoCrAlY bonding layer obtained in step (4) by atmospheric plasma spraying technology to form a TiO2-Dy3TaO7 ceramic layer. The parameters in the ceramic layer preparation process are: spraying distance 150 mm, spray gun movement speed 450 mm / s, spraying voltage 80 V, spraying current 480 A, powder feeding rate 40 g / min, powder feeding argon flow rate 80 SLPM, hydrogen flow rate 12 SLPM, and finally the thickness of the TiO2-Dy3TaO7 ceramic layer obtained is 210 μm.

[0063] Comparative Example 2

[0064] (1) Weigh 34.28 g of ZrO2 and 14.26 g of Y2O3 with a purity of 99% (percentage by mass) and mix them. Use isopropyl alcohol as a medium to wet ball mill the mixture for 18 h at a speed of 280 r / min. The mixed powder obtained by ball milling is baked at 70°C for more than 2.5 h to obtain a mixed powder.

[0065] (2) The mixed powder obtained in step (1) was sintered in the atmosphere at 1500°C for 18 hours, and then granulated using a spray drying technique. The obtained spray powder had high sphericity and good fluidity, and was then sieved to obtain 7YSZ:(Y2O3) with a particle size of 40-100 μm. 0.07 -(ZrO2) 0.93 Spray powder.

[0066] (3) The surface of the nickel-based alloy was ground and polished using silicon carbide sandpaper, and then 40-mesh aluminum oxide sand was selected and sandblasted to roughen the ground and polished surface using a sandblasting machine. The alloy substrate was then ultrasonically cleaned in alcohol for 8 minutes to remove the residual sand and oil on the alloy surface.

[0067] (4) A NiCoCrAlY bonding layer was prepared on the surface of the nickel-based alloy obtained in step (3) using supersonic plasma spraying technology. The composition of NiCoCrAlY was the following substances in percentage by mass: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y. The spraying distance was 240 mm, the spray gun movement speed was 500 mm / s, the spraying voltage was 130 V, the spraying current was 380 A, the spraying pressure was 0.65 MPa, the powder feeding rate was 40 g / min, the spraying gas source was Ar gas and compressed air, the compressed air flow rate was 16 SLPM, the auxiliary gas argon flow rate was 50 SLPM, and the thickness of the NiCoCrAlY bonding layer was 160 μm. A nickel-based alloy sprayed with a NiCoCrAlY bonding layer was obtained.

[0068] (5) The 7YSZ:(Y2O3) obtained in step (2) is sprayed by atmospheric plasma technology. 0.07 -(ZrO2) 0.93 The spray powder is deposited on the surface of the nickel-based alloy of the NiCoCrAlY bonding layer obtained in step (4) to form 7YSZ: (Y2O3) 0.07 -(ZrO2) 0.93 The parameters during the ceramic layer preparation process were: spraying distance 180 mm, spray gun movement speed 500 mm / s, spraying voltage 80 V, spraying current 480 A, powder feeding rate 30 g / min, argon feeding flow rate 100 SLPM, and hydrogen flow rate 10 SLPM. The final 7YSZ ceramic layer had a thickness of 210 μm.

[0069] Comparative Example 3

[0070] (1) Weigh 38.68 g of 99% pure ZrO2 and 10.42 g of Y2O3 and mix them using a wet ball mill with isopropyl alcohol for 25 h at a speed of 280 r / min. The resulting mixed powder is then baked at 70°C for at least 2.5 h to obtain a mixed powder.

[0071] (2) The mixed powder obtained in step (1) was sintered in the atmosphere at 1480°C for 20 hours, and then granulated using a spray drying technique. The obtained spray powder had high sphericity and good fluidity, and was then sieved to obtain 8YSZ:(Y2O3) with a particle size of 30-100 μm. 0.08 -(ZrO2) 0.92 Spray powder.

[0072] (3) The surface of the nickel-based alloy was ground and polished using silicon carbide sandpaper, and then 25-mesh aluminum oxide sand was selected and sandblasted to roughen the ground and polished surface using a sandblasting machine. The alloy substrate was then ultrasonically cleaned in alcohol for 10 minutes to remove the residual sand and oil on the alloy surface.

[0073] (4) A NiCoCrAlY bonding layer was prepared on the surface of the nickel-based alloy obtained in step (3) using supersonic plasma spraying technology. The composition of NiCoCrAlY included the following substances in mass percentage: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y. The spraying distance was 260 mm, the spray gun movement speed was 520 mm / s, the spraying voltage was 130 V, the spraying current was 380 A, the spraying pressure was 0.65 MPa, the powder feeding rate was 36 g / min, the spraying gas source was Ar gas and compressed air, the compressed air flow rate was 16 SLPM, the auxiliary gas argon flow rate was 60 SLPM, and the thickness of the NiCoCrAlY bonding layer was 180 μm. A nickel-based alloy sprayed with a NiCoCrAlY bonding layer was obtained.

[0074] (5) The 8YSZ:(Y2O3) obtained in step (2) is sprayed by atmospheric plasma technology. 0.08 -(ZrO2) 0.92 The spray powder is deposited on the surface of the nickel-based alloy of the NiCoCrAlY bonding layer obtained in step (4) to form 8YSZ: (Y2O3) 0.08 -(ZrO2) 0.92 Ceramic layer. The parameters in the ceramic layer preparation process are: spraying distance 180mm, spray gun moving speed 500mm / s, spraying voltage 80V, spraying current 480A, powder feeding rate 30g / min, powder feeding argon flow rate 90SLPM, hydrogen flow rate 16SLPM, and finally the thickness of the 8YSZ ceramic layer obtained is 220μm.

[0075] After the 316 steel-based coating materials sprayed with corrosion-resistant thermal barrier coatings prepared in Comparative Examples 1 to 3 were subjected to a high-temperature thermal fatigue test at 1200°C for 1000 hours, it was found that after long-term high-temperature service, some areas of the ceramic coating had peeling phenomena. In addition, a large number of hole defects also appeared in the bonding layer.

[0076] The 316 steel-based materials sprayed with corrosion-resistant thermal barrier coatings prepared in Comparative Examples 1 to 3 were placed in a molten copper environment at 1200°C for 1000 hours and then polished. Detection revealed that the coatings and bonding layers prepared in the comparative examples had a large number of cracks and hole defects, and obvious corrosion peeling occurred, exposing the substrate to the surface and being affected to a certain extent.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a corrosion-resistant thermal barrier coating, characterized in that: The specific steps include: (1) Weigh ZrO2, Dy2O3, and Ta2O5 powders, mix them by ball milling, and then dry them; (2) sintering the mixture obtained in step (1), followed by conventional granulation, and finally sieving to obtain ZrO2-Dy3TaO7 ceramic powder; (3) polishing, sandblasting, and ultrasonic cleaning the surface of the substrate material; (4) using supersonic plasma spraying technology to spray NiCoCrAlY on the substrate obtained in step (3) to form a bonding layer; obtaining a substrate material sprayed with the NiCoCrAlY bonding layer; (5) depositing the ZrO2-Dy3TaO7 ceramic powder obtained in step (2) on the surface of the substrate material sprayed with the NiCoCrAlY bonding layer obtained in step (4) by atmospheric plasma spraying technology to form a substrate having a ZrO2-Dy3TaO7 ceramic layer; In step (4), the thickness of the NiCoCrAlY bonding layer prepared is 150-250 μm; the composition of NiCoCrAlY is the following substances in percentage by mass: 47.5% Ni, 23% Co, 16.7% Cr, 12.3% Al, and 0.5% Y; The thickness of the ZrO2-Dy3TaO7 ceramic layer prepared in step (5) is 150-240 μm, the molar content of each element in the ceramic layer is: Zr 10-20%, Dy 30-60%, Ta 10-20%, and the porosity of the corrosion-resistant thermal barrier coating is 8%-25%; The corrosion-resistant thermal barrier coating is applied to the surface of the spray gun used in the Isa furnace.

2. The method for preparing the corrosion-resistant thermal barrier coating according to claim 1, characterized in that: The mass ratio of ZrO2, Dy2O3, and Ta2O5 powders in step (1) is: 12.69~16.34:55.23~60.56:40.58~46.45, the purity of each powder is above 99%.

3. The method for preparing the corrosion-resistant thermal barrier coating according to claim 1, characterized in that: In step (1), the ball milling medium is anhydrous ethanol or deionized water, the ball milling mixing time is 10-20 hours, the rotation speed is 250-280 r / min; and the drying condition is baking at 60° C. to 70° C. for more than 1.5 hours.

4. The method for preparing the corrosion-resistant thermal barrier coating according to claim 1, characterized in that: In step (2), sintering is carried out in an atmosphere at 1450-1550° C. for 15-25 hours; and after sieving, the particle size of the ZrO 2 -Dy 3 TaO 7 ceramic powder is between 40 and 100 μm.

5. The method for preparing the corrosion-resistant thermal barrier coating according to claim 1, characterized in that: The substrate material in step (3) is 316 stainless steel; a polishing machine or sandpaper is used for grinding; 10-50 mesh white corundum sand is used for sandblasting, and the air pressure is 0.15-0.55 MPa. The sandblasting distance is 110-130 mm, the sandblasting angle is 50-60°, and the sandblasting time is 40-60 s. The ultrasonic cleaning treatment uses any one of alcohol, kerosene or acetone solutions to ultrasonically clean the substrate, and the ultrasonic cleaning time is 8 min to 20 min.

6. The method for preparing the corrosion-resistant thermal barrier coating according to claim 1, characterized in that: In step (4), the spraying distance is 200-400 mm, the spray gun moving speed is 450-550 mm / s, the spraying voltage is 120-130 V, the spraying current is 350-400 A, the spraying pressure is 0.65-0.75 MPa, the powder feeding rate is 30-50 g / min, the spraying gas source is Ar gas and compressed air, the compressed air flow rate is 10-20 SLPM, and the auxiliary gas argon flow rate is 50-100 SLPM.

7. The method for preparing the corrosion-resistant thermal barrier coating according to claim 1, characterized in that: When the ZrO2-Dy3TaO7 ceramic layer is sprayed on the bonding layer using atmospheric plasma spraying-physical vapor deposition technology in step (5), the vacuum in the cabin is evacuated to 0.6-0.8 mbar, and then argon is backfilled to 30-35 mbar and the spray gun is ignited. The vacuum is then evacuated to 1.8-2.0 mbar, the preheating temperature is 900-950°C, and the ceramic layer is started to be sprayed. The parameters for preparing the ceramic layer are: spraying distance 100-180 mm, spray gun movement speed 300-500 mm / s, spraying voltage 60-100 V, spraying current 450-600 A, powder feeding rate 30-40 g / min, powder feeding argon flow rate 60-120 SLPM, and hydrogen flow rate 10-20 SLPM.

8. Applying the corrosion-resistant thermal barrier coating according to any one of claims 1 to 7 to the surface of a spray gun used in an Isa furnace.

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