A method for pre-treating the surface of a thermal barrier coating using PS-PVD and a method for preparing the thermal barrier coating

Abstract

The present invention provides a method for surface pretreatment of a thermal barrier coating using PS-PVD and a method for preparing the thermal barrier coating, and relates to the technical field of thermal barrier coatings. The present invention preheats the substrate to be treated to 300-800°C, which can avoid the preferential reaction of O2 with the blade surface to form a pre-oxidation layer under high temperature conditions; in the PS-PVD process, the reaction gas plasma is used to achieve rapid, efficient, and thorough in-situ cleaning and activation of the substrate surface, and the substrate surface is cleaned and activated uniformly, and can directly react with O2 to form a pre-oxidation layer after preheating. The surface pretreatment method provided by the present invention has a simple and efficient process, low raw material cost and process cost, can achieve in-situ pretreatment, and can evenly treat the surface of complex parts. It can provide a clean and activated surface for the subsequent deposition of the thermal barrier coating, ensure good bonding with the thermal barrier coating, and the interface after treatment is well bonded, free of pollutant residues and stress damage.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal barrier coatings, and in particular to a method for pre-treating the surface of a thermal barrier coating by using PS-PVD and a method for preparing the thermal barrier coating. Background Art

[0002] Plasma spray physical vapor deposition (PS-PVD) is a new thermal barrier coating preparation technology developed in recent years. It uses a high-speed plasma jet to deposit coatings on workpieces, which greatly suppresses the "shadow effect" during coating deposition, which is beneficial to improving the uniformity of coating thickness on complex blade surfaces and enhancing the thermal protection effect of the coating.

[0003] In order to achieve good coating interface bonding, the blade components need to be pre-treated before the coating is deposited using the above-mentioned technologies. Currently, coating surface pre-treatment methods mainly include: using sandblasting to increase surface roughness, using ion beams to bombard and clean the surface, and using plasma arcs to remove surface oxide films. Among them, sandblasting is currently the most widely used coating pre-treatment method, and sandblasting includes dry sandblasting (such as CN115404429A and CN113186484A) and wet sandblasting (such as CN111962028A and CN110923638A). Currently, advanced aero-engine blades are made of single crystal materials to form high-cooling-efficiency, ultra-thin-wall blade components. When solid sandblasting media such as white corundum are used to sandblast the blades, the sandblasting media that enters the blades is difficult to flow out through ultrasonic cleaning due to the complex internal cavity of the blades, which will pose a hidden danger to the safe service of the blades. In addition, the compressive stress introduced by sandblasting may cause recrystallization of the single crystal alloy structure, reducing the mechanical properties of the thin-walled blades. It is not suitable for the interface pre-treatment of thermal barrier coatings on hot-end components such as thin-walled single crystal blades of advanced aero-engines. By utilizing the characteristics of the plasma arc, a voltage is applied between the workpiece and the plasma gun (negative bias for the workpiece and positive bias for the plasma gun) to trigger the transferred arc, which can effectively remove the oxide film on the blade surface (Takeda K, Ito M, Takeuchi S. Propertiesof coatings and applications of low pressure plasma spray[J]. Pure & AppliedChemistry, 1990, 62(9): 1773-1782.). However, the application of this method is limited by factors such as working pressure and surface damage tolerance of parts. Currently, it can only be applied to low-pressure plasma spraying (VPS) processes. Using ion beams to bombard parts for cleaning (e.g., CN215997684U, CN108505006A) is beneficial for improving the interfacial bonding strength of the subsequent deposited coating. However, when applied to thermal barrier coating parts, due to its low cleaning rate, it cannot effectively treat parts with a large amount of surface oxide residue. Therefore, it is of great significance to provide a surface pretreatment method that can remove oxides at high speed and has no dielectric residue in the surface cavity. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a surface pretreatment method and preparation method for thermal barrier coatings using PS-PVD. The pretreatment method provided by the present invention has the characteristics of high-speed removal of oxides, no dielectric residue in the surface cavity and no stress damage.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for pre-treating the surface of a thermal barrier coating using PS-PVD, which is characterized by comprising the following steps:

[0007] (1) placing a substrate to be processed in a vacuum chamber of a PS-PVD device, and then preheating the substrate to be processed using a plasma flame flow after evacuation to obtain a preheated substrate; the vacuum degree of the vacuum chamber is 100-300 Pa; the surface of the substrate to be processed has a metal bonding layer; the temperature of the preheated substrate is 300-800°C;

[0008] (2) ionizing and activating the reaction gas by using a plasma flame flow to obtain a reaction gas plasma; the reaction gas is a fluorine-containing organic refrigerant-oxygen mixed gas or a fluorine-containing organic refrigerant, and the oxygen content in the fluorine-containing organic refrigerant-oxygen mixed gas is based on the fact that all carbon in the fluorine-containing organic refrigerant reacts with oxygen to generate carbon dioxide;

[0009] (3) Utilizing the reaction gas plasma to clean and activate the surface of the preheated substrate to obtain a cleaned and activated substrate; the vacuum degree of the surface cleaning and activation is 100-300 Pa;

[0010] (4) preheating the cleaned and activated substrate for a second time using a plasma flame flow to obtain a cleaned, activated and preheated substrate; the temperature of the cleaned, activated and preheated substrate is 800-1100°C;

[0011] (5) causing the cleaned, activated, and preheated substrate to undergo an oxidation reaction with oxygen to form a pre-oxidation layer, thereby obtaining a surface pre-treated substrate;

[0012] There is no chronological order for steps (1) and (2).

[0013] Preferably, the metal bonding layer includes a NiPtAl bonding layer or a NiCrAlYSi bonding layer.

[0014] Preferably, the first preheating conditions include: a plasma gun power of 20-30 kW, and a plasma flame working distance of 500-1500 mm.

[0015] Preferably, the fluorine-containing organic refrigerant and the fluorine-containing organic refrigerant in the fluorine-containing organic refrigerant-oxygen mixed gas independently include Freon; and the total flow rate of the reaction gas is preferably 0.3-2 L / min.

[0016] Preferably, the second preheating condition includes: the plasma gun power is 30-60 kW.

[0017] Preferably, the flow rate of oxygen for the oxidation reaction is 0.5~3 L / min.

[0018] The present invention provides a method for preparing a thermal barrier coating, comprising the following steps:

[0019] The ceramic layer raw material powder transported to the PS-PVD equipment is gasified by using a plasma flame flow, and a plasma physical vapor deposition ceramic layer is formed on the surface of the surface pre-treated substrate obtained by the surface pre-treatment method described in the above technical solution to obtain a PS-PVD thermal barrier coating.

[0020] Preferably, the ceramic layer includes an 8YSZ ceramic layer.

[0021] Preferably, the ceramic layer further comprises a Gd2Zr2O7 ceramic layer located on the surface of the 8YSZ ceramic layer;

[0022] The thickness of the 8YSZ ceramic layer and the Gd2Zr2O7 ceramic layer are independently 20-300 μm.

[0023] Preferably, the particle size of the raw material powder of the ceramic layer is 5-20 μm, and the powder feeding rate is 2-20 g / min;

[0024] The vacuum degree of the plasma physical vapor deposition is 100-300 Pa, and the power of the plasma gun is 30-60 kW.

[0025] The present invention preheats the substrate to be treated to 300-800°C, preventing the preferential reaction of oxygen with the blade surface to form a pre-oxidation layer under high-temperature conditions. During the PS-PVD process, the present invention utilizes a gaseous substance (reactant gas plasma) to achieve rapid, efficient, and thorough in-situ cleaning and activation of the substrate surface. This uniformly reacts with the metal bonding layer on the substrate surface to be treated, eliminating the uncertainty introduced by manual operation. This ensures uniform cleaning and activation of the substrate surface. The cleaned and activated surface can then react directly with oxygen at high temperatures, facilitating the formation of a pre-oxidation layer and improving interfacial adhesion with the subsequently deposited thermal barrier coating. The pre-oxidation layer also contributes to the coating's antioxidant properties. The present invention avoids the use of solid blasting media such as white corundum, avoiding blasting media residue and recrystallization induced by blasting pressure. This prevents degradation of the mechanical properties of thin-walled blades, helps extend the service life and reliability of the substrate after thermal barrier coating deposition, and eliminates the subsequent ultrasonic cleaning step required in traditional blasting processes, thereby reducing costs and increasing efficiency. Compared to ion beam surface bombardment cleaning methods, the present invention utilizes a gaseous substance (reactive gas plasma) for in-situ cleaning and activation of substrate surfaces. This cleaning and activation method is fast and efficient, and can effectively and deeply treat substrates with significant residual oxides. The surface pretreatment method provided by the present invention features simple and efficient processes, low raw material and process costs, the ability to perform in-situ pretreatment, and uniform surface treatment of complex parts. It provides a clean, activated surface for subsequent deposition of thermal barrier coatings, ensuring good adhesion to the thermal barrier coating. Compared to traditional coating pretreatment methods, the surface pretreatment method provided by the present invention offers advantages such as good interfacial bonding, no residual contaminants, and no stress damage.

[0026] The plasma physical vapor deposition (PS-PVD) method employed in this invention offers excellent wraparound coating properties, and since the substrate (e.g., blade) is completely enclosed in the plasma beam, the coating achieves excellent uniformity. For multi-piece turbine guide blades, which typically have complex structures and multiple blind spots, the PS-PVD method employed in this invention exhibits robust wraparound coating properties, enabling non-line-of-sight deposition and avoiding complex blade movement during spraying. The resulting composite thermal barrier coating exhibits excellent thickness uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the PS-PVD equipment used in the present invention, wherein: 1- plasma gun, 2- turntable, 3- substrate to be treated, 4- plasma flame, 5- reaction gas inlet, 6- vacuum chamber, 7- vacuum system, 8- filter chamber, 9- temperature measuring thermocouple;

[0028] Figure 2The SEM morphology comparison of the blade surface before and after surface cleaning and activation in Example 1, wherein the left picture is before surface cleaning and activation, and the right picture is after surface cleaning and activation;

[0029] Figure 3 This is a SEM morphology image of the near-surface cross-section of the surface-cleaned and activated blade obtained by surface cleaning and activation in Example 1;

[0030] Figure 4 This is a cross-sectional SEM morphology image of the PS-PVD thermal barrier coating prepared in Example 1;

[0031] Figure 5 This is a cross-sectional SEM morphology of the PS-PVD thermal barrier coating prepared in Example 2. DETAILED DESCRIPTION

[0032] The present invention provides a method for pre-treating the surface of a thermal barrier coating using PS-PVD, comprising the following steps:

[0033] (1) placing a substrate to be processed in a vacuum chamber of a PS-PVD device, and then preheating the substrate to be processed using a plasma flame flow after evacuation to obtain a preheated substrate; the vacuum degree of the vacuum chamber is 100-300 Pa; the surface of the substrate to be processed has a metal bonding layer; the temperature of the preheated substrate is 300-800°C;

[0034] (2) ionizing and activating the reaction gas by using a plasma flame flow to obtain a reaction gas plasma; the reaction gas is a fluorine-containing organic refrigerant-oxygen mixed gas or a fluorine-containing organic refrigerant, and the oxygen content in the fluorine-containing organic refrigerant-oxygen mixed gas is based on the fact that all carbon in the fluorine-containing organic refrigerant reacts with oxygen to generate carbon dioxide;

[0035] (3) Utilizing the reaction gas plasma to clean and activate the surface of the preheated substrate to obtain a cleaned and activated substrate; the vacuum degree of the surface cleaning and activation is 100-300 Pa;

[0036] (4) preheating the cleaned and activated substrate for a second time using a plasma flame flow to obtain a cleaned, activated and preheated substrate; the temperature of the cleaned, activated and preheated substrate is 800-1100°C;

[0037] (5) causing the cleaned, activated, and preheated substrate to undergo an oxidation reaction with oxygen to form a pre-oxidation layer, thereby obtaining a surface pre-treated substrate;

[0038] There is no chronological order for steps (1) and (2).

[0039] Unless otherwise specified, the raw materials used in the present invention are all commercially available products.

[0040] The present invention places a substrate to be processed in a vacuum chamber of a PS-PVD device, and after evacuation, uses a plasma flame flow to preheat the substrate to be processed to obtain a preheated substrate; the vacuum degree of the vacuum chamber is 100-300 Pa; the surface of the substrate to be processed has a metal bonding layer; and the temperature of the preheated substrate is 300-800°C.

[0041] In the present invention, the PS-PVD equipment preferably includes a vacuum chamber 6, a filter chamber 8 connected to the vacuum chamber 6, and a vacuum system 7 connected to the transition chamber 8; a plasma gun 1 and a turntable 2 are provided in the vacuum chamber 6; the function of the plasma gun 1 is to spray a plasma flame flow 4; the substrate 3 to be processed is set on the turntable 2, and the turntable 2 is provided with a temperature measuring thermocouple 9; and a reaction gas inlet 5 is also provided at the top of the vacuum chamber 6.

[0042] In the present invention, the metal bonding layer preferably comprises a NiPtAl bonding layer or a NiCrAlYSi bonding layer. The present invention does not specifically limit the method for preparing the metal bonding layer; it can be prepared using physical vapor deposition or chemical vapor deposition methods well known to those skilled in the art. In the present invention, the substrate to be treated is preferably a high-temperature alloy having a metal bonding layer. The present invention does not specifically limit the high-temperature alloy; it can be a high-temperature alloy well known to those skilled in the art. In a specific embodiment of the present invention, the high-temperature alloy is preferably a high-temperature alloy for aircraft engine blades or gas turbine blades, more preferably a thin-walled single crystal blade for an advanced aircraft engine.

[0043] In the present invention, during the entire surface pretreatment and subsequent deposition of the PS-PVD thermal barrier coating, the vacuum degree of the vacuum chamber 6 is maintained at 100-300 Pa, preferably 150-250 Pa.

[0044] In the present invention, the first preheating conditions include: a plasma gun power of 20-30 kW, preferably 25 kW; a plasma flame working distance (i.e., the distance between the plasma gun outlet and the substrate to be treated) of preferably 500-1500 mm, more preferably 1000 mm. In the present invention, the preheating temperature of the substrate is preferably 400-700°C, more preferably 500-600°C.

[0045] The present invention utilizes a plasma flame to ionize and activate the reaction gas to obtain a reaction gas plasma. In the present invention, the reaction gas is a fluorine-containing organic refrigerant-oxygen mixed gas or a fluorine-containing organic refrigerant, and the total flow rate of the reaction gas is preferably 0.3 to 2 L / min, more preferably 0.5 to 1.5 L / min; the fluorine-containing organic refrigerant and the fluorine-containing organic refrigerant in the fluorine-containing organic refrigerant-oxygen mixed gas independently preferably include Freon, more preferably include one or more of difluorochloromethane (R22), difluoromethane (R32) and tetrafluoroethane (R134a). In the present invention, the oxygen content in the fluorine-containing organic refrigerant-oxygen mixed gas is based on the reaction of all carbon in the fluorine-containing organic refrigerant with oxygen to produce carbon dioxide. Taking tetrafluoroethane as an example, the reaction occurring during the ionization activation process is: 2CHF2CHF2+5O2=4CO2+2H2O+4F - The C formed by the decomposition of Freon reacts and consumes completely with O, avoiding the formation of C deposition on the blade surface, and carbon dioxide and water vapor are discharged from the PS-PVD equipment.

[0046] After obtaining the reaction gas plasma, the present invention utilizes the reaction gas plasma to clean and activate the surface of the preheated substrate, thereby obtaining a cleaned and activated substrate; the vacuum degree of the surface cleaning and activation is 100-300 Pa. In the present invention, when the reaction gas is a fluorine-containing organic refrigerant-oxygen mixed gas, the reaction gas plasma (fluoride ions) reacts with oxides (e.g., Al2O3, Cr2O3) on the surface of the preheated substrate to generate gaseous metal fluorides (e.g., volatile AlF3, CrF3), which are then extracted by the vacuum system 7 and condensed through the filter chamber 8 before being discharged from the vacuum chamber 6, thereby achieving surface cleaning and activation of the preheated substrate. In the present invention, when the reaction gas is a fluorine-containing organic refrigerant, residual carbon deposits are formed on the surface of the resulting cleaned and activated substrate during the surface cleaning and activation. The residual carbon reacts with O2 during the subsequent oxidation reaction to form a gaseous CO2 product, simultaneously forming a pre-oxidation layer.

[0047] After obtaining the cleaned and activated substrate, the present invention performs a second preheating of the cleaned and activated substrate using a plasma flame to obtain a cleaned, activated, and preheated substrate. In the present invention, the temperature of the cleaned, activated, and preheated substrate is 800-1100°C, preferably 850-1050°C, and more preferably 900-1000°C. In the present invention, the conditions for the second preheating include: a plasma gun power of preferably 30-60 kW, more preferably 35-55 kW, and even more preferably 40-50 kW.

[0048] After obtaining the cleaned, activated, and preheated substrate, the present invention subjects the cleaned, activated, and preheated substrate to an oxidation reaction with oxygen to form a pre-oxidation layer, thereby obtaining a surface pre-treated substrate. In the present invention, the flow rate of oxygen for the oxidation reaction is preferably 0.5 to 3 L / min, more preferably 1 to 2.5 L / min, and even more preferably 1 to 2 L / min. In the present invention, the thickness of the pre-oxidation layer is preferably 0.5 to 2 μm, preferably 1 to 2 μm.

[0049] The present invention also provides a method for preparing a thermal barrier coating, comprising the following steps: utilizing a plasma flame flow to gasify the raw material powder of the ceramic layer transported to the PS-PVD equipment, and performing plasma physical vapor deposition on the surface of the surface pre-treated substrate obtained by the surface pre-treatment method described in the above technical scheme to obtain a PS-PVD thermal barrier coating.

[0050] In the present invention, the ceramic layer preferably includes an 8YSZ ceramic layer, and the raw material powder used for the ceramic layer is preferably 8YSZ powder, and the brand of the 8YSZ powder is preferably Metco 6700. In the present invention, the ceramic layer preferably also includes a Gd2Zr2O7 ceramic layer located on the surface of the 8YSZ ceramic layer, and the raw material powders used for the ceramic layer are 8YSZ ceramic powder and Gd2Zr2O7 ceramic powder in sequence, and the Gd2Zr2O7 ceramic layer is preferably further plasma-physical vapor deposited on the surface of the 8YSZ ceramic layer. In the present invention, the particle size of the raw material powder of the ceramic layer is preferably 5-20 μm, more preferably 10-15 μm, and the powder feeding rate of the raw material powder of the ceramic layer is preferably 2-20 g / min, more preferably 5-15 g / min, and further preferably 10 g / min. In the present invention, the thickness of the 8YSZ ceramic layer and the Gd2Zr2O7 layer are independently preferably 20 to 300 μm, more preferably 50 to 250 μm, and further preferably 100 to 200 μm.

[0051] In the present invention, the vacuum level of the plasma physical vapor deposition is 100-300 Pa, preferably 150-250 Pa, and more preferably 200 Pa; the plasma gun power is preferably 30-60 kW, more preferably 35-55 kW, and even more preferably 40-50 kW. In the present invention, during the plasma physical vapor deposition process, the surface pre-treated substrate does not move out of the beam area.

[0052] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] The brand of 8YSZ powder used in the following examples is Metco 6700, the fluorine-containing organic refrigerant used is tetrafluoroethane (R134a), and the particle size of the 8YSZ powder and Gd2Zr2O7 powder is 5-20 μm.

[0054] Example 1

[0055] use Figure 1 The device shown is used for surface pretreatment and spraying of thermal barrier coatings:

[0056] S1: Mount the blade part onto the turntable 2 of the PS-PVD equipment. After evacuation, ignite the plasma gun arc. After the plasma gun is operating stably, use the plasma flame to preheat the blade workpiece to 600°C to obtain a preheated blade. The vacuum degree of the vacuum chamber 6 is maintained at 150 Pa. The metal bonding layer on the blade surface is a NiPtAl metal bonding layer. The plasma gun power is 25 kW, and the working distance of the plasma flame is 1000 mm.

[0057] S2, the reaction gas (0.2L / min R134a and 1L / min O2) is introduced into the vacuum chamber, and the reaction gas reacts with the plasma flame to cause ionization and activation, thereby obtaining a reaction gas plasma;

[0058] S3, using the reaction gas plasma to clean and activate the surface of the preheated blade to obtain a surface-cleaned and activated blade, and the generated gaseous material is discharged from the vacuum chamber 6 along the vacuum system 7;

[0059] S4, preheating the surface cleaning and activation blade to 950°C, and introducing 1L / min of O2 into the vacuum chamber 6, where the O2 reacts with the surface of the surface cleaning and activation blade to form a pre-oxidation layer; the plasma gun power is 40kW; and the pre-oxidation layer thickness is 1.2μm;

[0060] In step S5, 8YSZ powder is fed into the PS-PVD plasma gun. The 8YSZ powder vaporizes within the plasma flame and deposits on the pre-oxidized layer to form an 8YSZ ceramic layer, resulting in a PS-PVD thermal barrier coating. The 8YSZ powder feed rate is 5 g / min, and the 8YSZ ceramic layer has a thickness of 120 μm.

[0061] Figure 2 The following is a comparison of the blade surface morphology before and after surface cleaning and activation. The left picture is before surface cleaning and activation, and the right picture is after surface cleaning and activation (i.e., the pre-oxidation layer is generated). Figure 2 It can be seen that after the surface pretreatment method provided by the present invention is used for surface pretreatment, the oxides on the blade surface are completely removed without any residue, and the blade body presents a metallic color.

[0062] Figure 3This is a cross-sectional morphology diagram of the near-surface area of ​​the surface-cleaned and activated blade (i.e., the blade with a pre-oxidized layer) prepared in this embodiment. As shown in Figure 3, the original metal bonding layer on the blade surface is intact, the surface is clean and undamaged, and there is no oxide residue.

[0063] Figure 4 This is the cross-sectional SEM morphology of the PS-PVD thermal barrier coating prepared in this example. Figure 4 It can be seen that after the surface pretreatment method provided by the present invention is used for surface pretreatment, a pre-oxidation layer of uniform thickness is generated on the surface of the NiPtAl metal bonding layer, and the deposited 8YSZ ceramic coating has a good interface bonding with the NiPtAl metal bonding layer without obvious hole defects.

[0064] Example 2

[0065] use Figure 1 The device shown is used for surface preparation and spraying of thermal barrier coatings:

[0066] S1: Mount the blade part onto the turntable 2 of the PS-PVD equipment. After evacuation, ignite the plasma gun arc. After the plasma gun is operating stably, use the plasma flame to preheat the blade workpiece to 500°C to obtain a preheated blade. The vacuum degree of the vacuum chamber 6 is maintained at 200 Pa. The metal bonding layer on the blade surface is a NiCrAlYSi metal bonding layer. The plasma gun power is 28 kW, and the working distance of the plasma flame is 1200 mm.

[0067] S2, 0.2L / min R134a is introduced into the vacuum chamber, and the reaction gas reacts with the plasma flame to cause ionization and activation, thereby obtaining a reaction gas plasma;

[0068] S3, using the reaction gas plasma to clean and activate the surface of the preheated blade to obtain a surface-cleaned and activated blade, and the generated gaseous material is discharged from the vacuum chamber 6 along the vacuum system 7, and a carbon deposition layer is formed on the surface of the surface-cleaned and activated blade;

[0069] S4, preheating the surface cleaning and activation blade to 1000°C, and introducing 1.5L / min of O2 into the vacuum chamber 6, wherein the O2 reacts with the carbon on the surface of the surface cleaning and activation blade to form a pre-oxidation layer; the plasma gun power is 45kW; and the thickness of the pre-oxidation layer is 1.5μm;

[0070] S5, feeding 8YSZ powder into the PS-PVD plasma gun, the 8YSZ powder is vaporized in the plasma flame and deposited on the surface of the pre-oxidized layer to form an 8YSZ ceramic layer; the feeding rate of the 8YSZ powder is 7 g / min, and the thickness of the 8YSZ ceramic layer is 100 μm;

[0071] S6. Gd2Zr2O7 powder is fed into the PS-PVD plasma gun. The Gd2Zr2O7 powder vaporizes within the plasma flame and then deposits on the surface of the 8YSZ ceramic layer to form a Gd2Zr2O7 ceramic layer, thereby obtaining a PS-PVD thermal barrier coating. The Gd2Zr2O7 powder feed rate is 7 g / min, and the Gd2Zr2O7 ceramic layer has a thickness of 80 μm.

[0072] Figure 5 This is the cross-sectional SEM morphology of the PS-PVD thermal barrier coating prepared in this example. Figure 5 It can be seen that after the surface pretreatment method provided by the present invention is used for surface pretreatment, a pre-oxidation layer of uniform thickness is generated on the surface of the NiCrAlYSi metal bonding layer, and the deposited 8YSZ+Gd2Zr2O7 ceramic layer has a good interface bonding with the NiCrAlYSi metal bonding layer, without obvious hole defects and abnormal defects.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for pre-treating the surface of a thermal barrier coating using PS-PVD, characterized in that: The following steps are involved: (1) placing a substrate to be processed in a vacuum chamber of a PS-PVD device, and then preheating the substrate to be processed using a plasma flame flow after evacuation to obtain a preheated substrate; the vacuum degree of the vacuum chamber is 100-300 Pa; the surface of the substrate to be processed has a metal bonding layer, and the metal bonding layer includes a NiPtAl bonding layer or a NiCrAlYSi bonding layer; the temperature of the preheated substrate is 300-800° C.; the substrate is a blade, and the material of the blade is a high-temperature alloy; (2) ionizing and activating a reaction gas by using a plasma flame flow to obtain a reaction gas plasma; the reaction gas is a fluorine-containing organic refrigerant-oxygen mixed gas or a fluorine-containing organic refrigerant, and the oxygen content in the fluorine-containing organic refrigerant-oxygen mixed gas is based on the fact that all carbon in the fluorine-containing organic refrigerant reacts with oxygen to generate carbon dioxide; the fluorine-containing organic refrigerant and the fluorine-containing organic refrigerant in the fluorine-containing organic refrigerant-oxygen mixed gas independently include Freon; (3) using the reaction gas plasma to clean and activate the surface of the preheated substrate to obtain a cleaned and activated substrate; the vacuum degree of the surface cleaning and activation is 100 to 300 Pa; (4) preheating the cleaned and activated substrate for a second time by using a plasma flame flow to obtain a cleaned, activated and preheated substrate; the temperature of the cleaned, activated and preheated substrate is 800 to 1100° C.; (5) subjecting the cleaned, activated, and preheated substrate to an oxidation reaction with oxygen to form a pre-oxidation layer, thereby obtaining a surface pre-treated substrate; There is no chronological order for steps (1) and (2).

2. The surface pretreatment method according to claim 1, characterized in that: The first preheating conditions include: a plasma gun power of 20-30 kW, and a plasma flame working distance of 500-1500 mm.

3. The surface pretreatment method according to claim 1, characterized in that: The total flow rate of the reaction gas is 0.3-2 L / min.

4. The surface pretreatment method according to claim 1, characterized in that: The second preheating condition includes: the plasma gun power is 30-60 kW.

5. The surface pretreatment method according to claim 1, characterized in that: The flow rate of oxygen used in the oxidation reaction is 0.5 to 3 L / min.

6. A method for preparing a thermal barrier coating, characterized in that: The following steps are involved: The ceramic layer raw material powder transported to the PS-PVD equipment is gasified by using a plasma flame flow, and a plasma physical vapor deposition ceramic layer is formed on the surface of the surface pre-treated substrate obtained by the surface pre-treatment method according to any one of claims 1 to 5 to obtain a PS-PVD thermal barrier coating.

7. The preparation method according to claim 6, characterized in that The ceramic layer includes an 8YSZ ceramic layer.

8. The preparation method according to claim 7, characterized in that The ceramic layer further includes a Gd2Zr2O7 ceramic layer located on the surface of the 8YSZ ceramic layer; The thickness of the 8YSZ ceramic layer and the Gd2Zr2O7 ceramic layer are independently 20 to 300 μm.

9. The preparation method according to claim 6, 7 or 8, characterized in that: The particle size of the ceramic layer raw material powder is 5 to 20 μm, and the powder feeding rate is 2 to 20 g / min; The vacuum degree of the plasma physical vapor deposition is 100-300 Pa, and the power of the plasma gun is 30-60 kW.

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