Method for preparing double-phase thermal barrier coating MCrAlY bonding layer through multi-arc ion plating

Abstract

The invention discloses a method for preparing a double-phase thermal barrier coating MCrAlY bonding layer through multi-arc ion plating, which comprises the following steps of: firstly, determining element components of the double-phase MCrAlY bonding layer to be prepared, and carrying out phase diagram calculation on phases and the element components in the double-phase MCrAlY bonding layer to obtain element components of gamma phase and beta phase; then preparing a gamma-phase target material and a beta-phase target material respectively according to the element components of the gamma phase and the beta phase by adopting a vacuum arc melting method; the MCrAlY coating is deposited on the surface of the pretreated substrate material by adjusting the target current, heat treatment is conducted in the vacuum state, and the non-element concentration gradient or element concentration gradient double-phase thermal barrier coating MCrAlY bonding layer is obtained; by adopting the gamma-phase and beta-phase dual-phase target material, the flexibility of regulating and controlling the element components and the phase components is improved, the expected element components of the coating can be accurately realized, an Al-based target material does not need to be additionally prepared, and the coating with the Al element concentration gradient can be obtained only by regulating the current of the dual-phase target material; the method has the characteristics of low cost, high efficiency and high precision.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal barrier coating materials, and in particular relates to a method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating. Background Art

[0002] Thermal barrier coatings have become an indispensable thermal protection material for the surface of turbine blades of aircraft engines, marine gas turbines and gas turbines for power plants. Thermal barrier coatings can effectively reduce the surface temperature of turbine blades and improve the service performance of turbine blades. Commercial thermal barrier coatings are mainly divided into two layers: an outer ceramic insulation layer and an inner metal bonding layer. At present, there are two main preparation methods for bonding layers: a diffusion-type NiAl bonding layer, which is mainly prepared by infiltrating Al elements on a high-temperature alloy substrate; an epitaxial MCrAlY bonding layer, where M is Ni or / and Co, and the bonding layer preparation method mainly includes plasma spraying, supersonic flame spraying, multi-arc ion plating, electron beam physical vapor deposition and other technologies. For advanced thermal barrier coatings on the surface of turbine blades, the method of preparing the metal bonding layer by multi-arc ion plating technology and the outer ceramic layer by electron beam physical vapor deposition has become the most concerned preparation method and has also been industrialized. The bonding layer prepared by multi-arc ion plating has the advantages of dense structure, pure phase, uniform thickness, smooth interface, and no oxide doping. Therefore, multi-arc ion plating technology has become the most critical technology for preparing the bonding layer of thermal barrier coatings.

[0003] The following disadvantages exist in the process of preparing MCrAlY bonding layer by multi-arc ion plating:

[0004] 1. The existing MCrAlY prepared by multi-arc ion plating is mainly composed of two phases, namely γ-Ni phase and β-NiAl phase, and the target material used to prepare the coating is also composed of these two phases. In the multi-arc ion plating preparation process, it is necessary to determine the elemental composition in the MCrAlY coating in advance and prepare the corresponding target material, and then evaporate the target material to prepare the coating. Once the target material composition is determined, the physical phase and elemental composition in the coating cannot be adjusted, and the physical phase and elemental composition remain consistent and uniform throughout the thickness of the coating. If a coating with different phase contents is required, the target material needs to be redesigned and processed. This method of redesigning the target material is not only inefficient, but also costly and time-consuming.

[0005] Second, since the target material in the process of preparing MCrAlY bonding layer by the traditional multi-arc ion plating method is composed of γ-Ni phase and β-NiAl phase, the different melting points of the two phases during coating preparation lead to different ionization rates of elements such as Ni, Cr, and Al, which ultimately leads to the elemental composition of the prepared coating being different from that of the designed target material.

[0006] 3. Since the target material composition has been determined during the preparation of the MCrAlY bonding layer by the traditional multi-arc ion plating method, the phase composition and elemental composition of the prepared coating remain uniform throughout the coating thickness direction, and it is impossible to prepare a coating with an element concentration gradient. Since the failure mechanism of the thermal barrier coating / blade caused by the traditional MCrAlY bonding layer is mainly the excessive oxidation of the bonding layer and the elemental interdiffusion between the bonding layer and the high-temperature alloy blade substrate, the oxidation resistance of the bonding layer requires a higher concentration of Al element, and the interdiffusion between the bonding layer and the substrate is mainly caused by the higher Al concentration of the bonding layer than the substrate. Therefore, in order to solve the two problems of oxidation and interdiffusion at the same time, it is necessary to prepare a bonding layer with a low Al concentration on the inner side (the side bonded with the high-temperature alloy) and a high Al concentration on the outer side (the side bonded with the ceramic layer) with an Al concentration distribution gradient, and the traditional multi-arc ion plating preparation method cannot achieve the preparation of such a coating.

[0007] Wei et al. (Y. Wei, S. Zheng, J. Pu, D. Zhou, L. Wang, W. Guo, G. He. Effect of aluminum concentration on microstructure and evolution behavior of oxide layer on NiAlSiY coating at 500℃. Corrosion Science, 2020, 165: 108400.) designed a dual-target scheme for preparing NiAlSiY coating using multi-arc ion plating, which achieved adjustable Al concentration in the coating. The dual targets were Ni-4.5Si-2.5Y and Al targets. The prepared bonding layer material is a multiphase structure, including β-NiAl phase, γ'-Ni3Al phase, Al3Ni phase, Al phase, etc. Xu et al. (C.Xu, S.Jiang, Z.Bao, J.Gong, C.Sun.Isothermal oxidation behavior ofagradientNiCoCrAlSiY coating depositedby arc ionplating on a Ni-based singlecrystal superalloy.Corrosion Science,2009,51(6):1467-74.)(S.Jiang,C.Xu,H.Li,J.Ma,J.Gong,C.Sun.High temperature corrosion behavior ofagradientNiCoCrAlYSi coating I:Microstructure evolution.Corrosion Science,2010,52(5):1746-52.) used NiCoCrAlYSi target and pure Al target and multi-arc ion plating technology to prepare MCrAlY bonding layer material with Al element concentration gradient. The bonding layer contains β-NiAl phase, γ-Ni phase, γ'-Ni3Al phase, Cr phase, etc.Ma et al. (J. Ma, S. Jiang, H. Li, W. Wang, J. Gong, C. Sun. Microstructure and oxidation behavior of an AlSiY / NiCrAlYSi composite coating at 1150C. Corrosion science, 2011, 53(4): 1417-23.) first prepared a double-layer coating of outer AlSiY and inner NiCrAlYSi, and used high-temperature heat treatment to make the outer AlSiY infiltrate the inner coating, and then prepared a concentration gradient coating.

[0008] However, no fundamental improvement has been made to the preparation of the traditional MCrAlY bonding layer. In these preparation methods, MCrAlY targets are used. Although Al targets or Al alloy targets can be used at the same time, only the change of Al concentration along the thickness direction of the coating or the change of Al concentration in the entire coating can be achieved, and the physical phases in the coating cannot be accurately regulated. For example, impurity phases such as α-Cr or γ'-Ni3Al will appear inside the coating. Because the coating phase is also related to elements such as Ni and Cr, the deposition method has not been fundamentally improved. In addition, there is still a technical problem in the preparation process of these coatings that the concentration of coating elements cannot be accurately controlled to achieve the expected value. Summary of the invention

[0009] In order to overcome the above-mentioned shortcomings in the prior art, the object of the present invention is to provide a method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating.

[0010] By adopting two target materials, that is, preparing the γ phase and β phase in the coating into target materials respectively, and igniting the two target materials at the same time during the preparation process, the preparation of a two-phase coating can be achieved, and the target current of the two target materials can be adjusted to achieve the regulation of the phase composition of the coating, which solves the technical problem that the content of the γ phase and β phase in the bonding layer in the existing multi-arc ion plating preparation process cannot be adjusted.

[0011] By adopting two target materials, γ and β, the ionization rate of the two targets can be adjusted by adjusting the target current, thereby adjusting the elemental composition in the coating, and finally obtaining the expected elemental composition of the coating. This solves the technical problem in the existing multi-arc ion plating preparation process that the different ionization rates caused by the different melting points between the γ phase and the β phase in the target material ultimately lead to the element / phase composition in the actual coating being different from the designed elemental composition of the target material.

[0012] By adopting a mode in which γ and β targets are separated, a coating with an element concentration gradient can be prepared by controlling the target current during the coating deposition process, that is, the current of the β target and the current of the β phase target are set to increase in a graded step-by-step manner, that is, a gradient that is low at the beginning and high at the end. The prepared MCrAlY bonding layer has a gradient characteristic of low Al concentration on the inside and high Al concentration on the outside, which solves the technical problem that the existing multi-arc ion plating process cannot prepare a coating with an element concentration gradient.

[0013] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows:

[0014] A method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating comprises the following steps:

[0015] Step 1: determining the elemental composition of the dual-phase MCrAlY bonding layer to be prepared, calculating the phase diagram of the physical phase and elemental composition in the dual-phase MCrAlY bonding layer, and obtaining the elemental composition of the γ phase and the β phase in the dual-phase MCrAlY bonding layer;

[0016] Step 2: adding the Y element in the MCrAlY bonding layer to be prepared to the elemental components of the γ phase and the β phase in the dual-phase MCrAlY bonding layer at the same time, and homogenizing all the elemental components; then using a vacuum arc melting method to prepare a γ phase target and a β phase target according to the elemental components of the γ phase and β phase after the homogenization treatment;

[0017] Step 3: using the prepared γ-phase target material and β-phase target material, and setting the target current, depositing the MCrAlY coating on the surface of the pretreated substrate material to obtain a non-element concentration gradient coating or an MCrAlY coating with an element concentration gradient;

[0018] Step 4: heat-treating the non-element concentration gradient coating or the MCrAlY coating with an element concentration gradient under a vacuum state to obtain a non-element concentration gradient or an element concentration gradient dual-phase thermal barrier coating MCrAlY bonding layer.

[0019] The element composition of the dual-phase MCrAlY bonding layer to be prepared in step 1 includes: in atomic percentage, 10-30wt.% Cr, 6-17wt.% Al, 0.1-1wt.% Y, and the rest is Ni or Co elements.

[0020] The element composition of the dual-phase MCrAlY bonding layer to be prepared in step 1 includes: in atomic percentage, 22-23wt.% Cr, 10-12wt.% Al, 0.5-1wt.% Y, and the rest is Ni or Co elements.

[0021] The step 1 uses Thermo-Calc software to calculate the phase diagram. The element types selected according to the dual-phase MCrAlY bonding layer to be prepared are Ni, Cr, Al or Co, Cr, Al. The Y element is not considered in the phase diagram calculation process; parameter definition: the temperature input is the heat treatment temperature of the substrate material, and the heat treatment temperature is 1000-1100° C. The element composition input is the element composition of the dual-phase MCrAlY bonding layer to be prepared after removing the Y element and the remaining elements are homogenized.

[0022] In the step 3, the prepared γ-phase target material and β-phase target material are set as a group of target materials, and a group of target materials are installed in the opposite direction of the substrate material, and the substrate material is rotated at a rotational angular velocity of 10-30 rpm to deposit the MCrAlY coating.

[0023] In step 3, the preparation process of the MCrAlY coating with non-element concentration gradient is as follows:

[0024] The currents of the γ-phase target and the β-phase target are both 80-150A, and the currents of the γ-phase target and the β-phase target are set to remain constant;

[0025] The preparation process of MCrAlY coating with element concentration gradient is as follows:

[0026] The current of the γ-phase target material is 80-150A, and the current of the γ-phase target material is kept constant; the current of the β-phase target material is 80-150A, and the current of the β-phase target material is increased in a graded step-by-step manner, that is, at the initial moment, the target current is low, and at the end moment, the target current is high.

[0027] During the preparation of the MCrAlY coating with element concentration gradient, at the initial moment of coating deposition, the current of the β-phase target is 80-100A, and gradually increases to 120-150A in a step-by-step manner as the deposition time increases. The number of levels is 2-6, and the deposition time of each level is the total deposition time / number of levels.

[0028] Other parameters of the multi-arc ion plating in step 3 are: total deposition time of 2-8h, argon gas flow rate of 60-180sccm, vacuum degree in the furnace chamber of 0.1-1.0Pa, preparation temperature of 250-400°C, and bias voltage of 100-200V.

[0029] In step 3, the base material is a nickel-based alloy, and the pretreatment operation is: grinding, polishing and cleaning the surface of the nickel-based alloy in sequence to keep the surface of the nickel-based alloy clean and mirror-like.

[0030] In step 4, the heat treatment temperature is 1000-1100° C. and the time is 2-6 hours.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Compared with the traditional single dual-phase MCrAlY, the present invention uses two types of target materials, γ and β, to prepare the dual-phase MCrAlY bonding layer, which greatly increases the flexibility of regulating the elemental composition and phase composition during the coating preparation process and increases the accuracy of coating preparation.

[0033] 2. The present invention calculates the physical phases and elemental composition in the dual-phase MCrAlY bonding layer through a phase diagram to obtain the elemental composition of the γ phase and the β phase in the dual-phase MCrAlY bonding layer. The target material elemental composition is designed and prepared accordingly, with very high efficiency and accuracy.

[0034] 3. The present invention prepares a two-phase MCrAlY bonding layer with an Al element concentration gradient by keeping the current of the γ-phase target material constant during the multi-arc ion plating preparation process and setting the current of the β-phase target material to increase in a limited step-by-step manner, that is, at the initial moment, the target current is low, and at the end moment, the target current is high.

[0035] In summary, compared with the prior art, the present invention utilizes a dual-phase target material to split the traditional single dual-phase MCrAlY target material into a γ-phase and β-phase dual-phase target material, which greatly increases the flexibility of regulating the elemental composition and phase composition during the coating preparation process, can accurately achieve the expected elemental composition of the coating, and there will be no element deviation between the prepared coating and the designed coating, and can effectively avoid the formation of phases such as α-Cr and γ'-Ni3Al in the coating, thereby increasing the accuracy of coating preparation. The present invention does not require additional preparation of Al-based targets, and can prepare a coating with an Al element concentration gradient only by adjusting the current of the γ-phase and β-phase dual-phase targets. The preparation method of the present invention can not only prepare a dual-phase thermal barrier coating MCrAlY bonding layer with a non-element concentration gradient, but also prepare a dual-phase thermal barrier coating MCrAlY bonding layer with an element concentration gradient, which has the characteristics of low cost, high efficiency, high precision and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of a method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating.

[0037] Figure 2 It is a schematic diagram of the installation of the γ-phase target and the β-phase target of the present invention.

[0038] Figure 3 This is a SEM image of the cross section of the non-element concentration gradient MCrAlY bonding layer prepared in Example 1 of the present invention.

[0039] Figure 4 This is a SEM image of the cross section of the non-element concentration gradient MCrAlY bonding layer prepared in Example 2 of the present invention.

[0040] Figure 5 This is a SEM image of the cross section of the non-element concentration gradient MCrAlY bonding layer prepared in Example 3 of the present invention, wherein: Figure 5 (a) is at low resolution. Figure 5 (b) is at high resolution.

[0041] Figure 6 This is a SEM image of the cross section of the element concentration gradient MCrAlY bonding layer prepared in Example 4 of the present invention.

[0042] Figure 7 This is a SEM image of the cross section of the element concentration gradient MCrAlY bonding layer prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further introduced below in conjunction with the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, a method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating comprises the following steps:

[0045] Step 1: Pre-treat the surface of the substrate material;

[0046] The base material is a nickel-based alloy, and the surface of the nickel-based alloy is grinded, polished and cleaned in sequence to keep the surface of the nickel-based alloy clean and mirror-like;

[0047] Step 2: determining the elemental composition of the dual-phase MCrAlY bonding layer to be prepared, performing phase diagram calculation on the physical phases and elemental composition in the dual-phase MCrAlY bonding layer, and obtaining the elemental composition of the γ phase and the β phase in the dual-phase MCrAlY bonding layer;

[0048] The element composition of the dual-phase MCrAlY bonding layer to be prepared includes: in atomic percentage, 10-30wt.% Cr, 6-17wt.% Al, 0.1-1wt.% Y, and the rest is Ni or Co; preferably 22-23wt.% Cr, 10-12wt.% Al, 0.5-1wt.% Y, and the rest is Ni or Co;

[0049] Thermo-Calc software was used to calculate the phase diagram. The calculation mode was single-point calculation. The system was the thermodynamic and kinetic database of nickel-based alloys. The element types selected according to the proposed dual-phase MCrAlY bonding layer were Ni, Cr, Al or Co, Cr, Al. The Y element was not considered in the phase diagram calculation process. Parameter definition: The temperature input was the heat treatment temperature of the substrate material, and the heat treatment temperature was 1000-1100°C. The element composition input was the element composition of the dual-phase MCrAlY bonding layer to be prepared after removing the Y element and homogenizing the remaining elements. The pressure was atmospheric pressure, and the element composition of the γ phase and the β phase in the dual-phase MCrAlY bonding layer was finally obtained.

[0050] Step 3: In step 2, the Y element in the MCrAlY bonding layer to be prepared is added to the elemental components of the γ phase and the β phase in the dual-phase MCrAlY bonding layer, and all the elemental components are homogenized; then, a γ phase target and a β phase target are prepared by vacuum arc melting according to the elemental components of the γ phase and the β phase after the homogenization treatment;

[0051] The preparation process of the γ-phase target and the β-phase target is as follows: nickel powder, cobalt powder, chromium powder, aluminum powder and yttrium powder with a purity of 99.99% are used, and the mixture is weighed according to the atomic percentage of each element in the bonding layer to be prepared, and the mixed powder is heated and melted by a vacuum melting method, the vacuum degree is 0.1Pa, the melting power is 40kW, the inert gas is argon, the melting times are three times, and the alloy ingot is obtained, and further cut and processed according to the actual target size required by the multi-arc ion plating machine;

[0052] Step 4: using the prepared γ-phase target material and β-phase target material, and setting the target current, depositing the MCrAlY coating on the surface of the pretreated substrate material to obtain the MCrAlY coating with no element concentration gradient or element concentration gradient;

[0053] like Figure 2 As shown, first, the substrate material pretreated in step 4 is vertically suspended on a sample stand and fixed in a vacuum coating chamber of a multi-arc ion coating machine, the γ-phase target material and the β-phase target material prepared in step 3 are set as a group of target materials, and a group of target materials are installed in opposite directions of the substrate material, and a non-element concentration gradient coating or an element concentration gradient coating is prepared by rotating the sample stand, and the rotation angular velocity is 10-30 revolutions / min;

[0054] The preparation process of MCrAlY coating with non-element concentration gradient is as follows:

[0055] The current of the γ-phase target is 80-150A, and the current of the β-phase target is 80-150A. The currents of the γ-phase target and the β-phase target are set to be constant. By adjusting the target currents of the two phases, the phase and element concentration in the MCrAlY bonding layer in the prepared coating can be controlled;

[0056] The preparation process of MCrAlY coating with element concentration gradient is as follows:

[0057] The current of the γ-phase target material is 80-150A, and the current of the γ-phase target material is kept constant; the current of the β-phase target material is 80-150A, and the current of the β-phase target material is increased in a graded step-by-step manner, that is, at the initial moment, the target current is low, and at the end moment, the target current is high;

[0058] At the initial moment of coating deposition, the current of the β-phase target is 80-100A, and gradually increases to 120-150A in a step-by-step manner as the deposition time increases. The number of levels is 2-6, and the deposition time of each level is the total deposition time / number of levels.

[0059] In the above preparation process, other parameters of multi-arc ion plating are: total deposition time is 2-8h, argon gas flow rate is 60-180sccm, vacuum degree in the furnace chamber is 0.1-1.0Pa, preparation temperature is 250-400℃, bias voltage is 100-200V;

[0060] Step 5: Heat treat the MCrAlY coating with non-element concentration gradient or element concentration gradient under vacuum to prevent oxidation of the coating during the heat treatment process. The heat treatment temperature is the same as the heat treatment temperature set in step 1, and the time is 2-6 hours. Finally, a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient or element concentration gradient is obtained.

[0061] Example 1

[0062] A method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating specifically comprises the following steps:

[0063] Step 1: Pre-treat the surface of the nickel-based alloy;

[0064] The surface of the nickel-based alloy is ground, polished and cleaned in sequence to keep the surface of the nickel-based alloy clean and mirror-like;

[0065] Step 2: determining the elemental composition of the dual-phase MCrAlY bonding layer to be prepared, the elemental composition comprising: in atomic percentage, 22wt.% Cr, 11wt.% Al, 0.5wt.% Y, and the rest being Ni; performing phase diagram calculation on the physical phases and elemental composition in the dual-phase MCrAlY bonding layer to obtain the elemental composition of the γ-Ni phase and the β-NiAl phase in the dual-phase MCrAlY bonding layer;

[0066] Thermo-Calc software was used to calculate the phase diagram. The calculation mode was single-point calculation. The system was a thermodynamic and kinetic database of nickel-based alloys. The elements selected according to the proposed dual-phase MCrAlY bonding layer were Ni, Cr, and Al. The Y element was not considered in the phase diagram calculation process. Parameter definition: the temperature input was 1000°C, and the element composition input was the element composition of the MCrAlY bonding layer to be prepared after removing the Y element and homogenizing the other elements, i.e., 66.83wt.%Ni, 22.11wt.%Cr, and 11.06wt.%Al. The pressure was atmospheric pressure. Finally, the element composition of the γ-Ni phase and the β-NiAl phase in the dual-phase MCrAlY bonding layer was obtained, i.e., the element composition of the γ-Ni phase was 66.36wt.%Ni, 27.67wt.%Cr, and 5.97wt.%Al, and the element composition of the β-NiAl phase was 72.61wt.%Ni, 17.08wt.%Al, and 10.31wt.%Cr.

[0067] Step 3: In step 2, 0.5wt.% of Y element is added to the elemental composition of the γ-Ni phase and the β-NiAl phase in the dual-phase MCrAlY bonding layer at the same time, and all the elemental compositions are homogenized to obtain an elemental composition of 66.07wt.% Ni, 27.56wt.% Cr, 5.87wt.% Al, and 0.5wt.% Y for the γ-Ni phase, and an elemental composition of 72.24wt.% Ni, 17.01wt.% Al, 10.25wt.% Cr, and 0.5wt.% Y for the β-NiAl phase; and then a γ-Ni phase target and a β-NiAl phase target are prepared by a vacuum melting method according to the elemental composition of the γ-Ni phase and the β-NiAl phase after the homogenization treatment, respectively;

[0068] Step 4: using the prepared γ-Ni phase target and β-NiAl phase target, depositing an MCrAlY coating on the surface of the pretreated substrate material to obtain an MCrAlY coating with a non-element concentration gradient;

[0069] The deposition time is 5 hours, the rotation angular velocity is 10 revolutions per minute, the current of the γ-Ni phase target is 80A, the current of the β-NiAl phase target is 90A, and the currents of the γ-Ni phase target and the β-NiAl phase target are set to remain constant; during the preparation process, the argon gas flow rate is 60 sccm, the vacuum degree in the furnace chamber is 0.1 Pa, the preparation temperature is 250° C., and the bias voltage is 100V;

[0070] Step 5: The MCrAlY coating with non-element concentration gradient is heat treated under vacuum to prevent oxidation of the coating during the heat treatment. The heat treatment temperature is 1000°C and the time is 2 hours. Finally, a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient is obtained.

[0071] Figure 3 This is a SEM image of the cross section of the MCrAlY bonding layer of the dual-phase thermal barrier coating prepared in Example 1. Figure 3 It can be seen that the coating is a typical γ and β phase dual-phase coating, in which the dark part is the β phase and the light part is the γ phase; the elemental composition in the coating is tested by inductively coupled plasma atomic emission spectrometry analysis technology, and the specific components measured are: 22.03wt.% Cr, 11.06wt.% Al, 0.52wt.% Y, which are the same as the expected elemental composition of the coating, indicating that the preparation method of the present invention can accurately prepare a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient.

[0072] Example 2

[0073] A method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating specifically comprises the following steps:

[0074] Step 1: Pre-treat the surface of the nickel-based alloy;

[0075] The surface of the nickel-based alloy is ground, polished and cleaned in sequence to keep the surface of the nickel-based alloy clean and mirror-like;

[0076] Step 2: determining the elemental composition of the dual-phase MCrAlY bonding layer to be prepared, the elemental composition comprising: in atomic percentage, 23wt.% Cr, 10wt.% Al, 1wt.% Y, and the rest being Ni; performing phase diagram calculation on the physical phases and elemental composition in the dual-phase MCrAlY bonding layer to obtain the elemental composition of the γ-Ni phase and the β-NiAl phase in the dual-phase MCrAlY bonding layer;

[0077] Thermo-Calc software was used to calculate the phase diagram. The calculation mode was single-point calculation. The system was a thermodynamic and kinetic database of nickel-based alloys. The elements selected according to the proposed dual-phase MCrAlY bonding layer were Ni, Cr, and Al. The Y element was not considered in the phase diagram calculation process. Parameter definition: the temperature input was 1100°C, the element composition input was the element composition of the MCrAlY bonding layer to be prepared after removing the Y element and homogenizing the other elements, i.e., 66.67wt.%Ni, 23.23wt.%Cr, and 10.1wt.%Al. The pressure was atmospheric pressure. Finally, the element composition of the γ-Ni phase and the β-NiAl phase in the dual-phase MCrAlY bonding layer was obtained, i.e., the element composition of the γ-Ni phase was 64.56wt.%Ni, 29.13wt.%Cr, and 6.31wt.%Al, and the element composition of the β-NiAl phase was 71.63wt.%Ni, 17.0wt.%Al, and 11.37wt.%Cr.

[0078] Step 3: In step 2, 1wt% of Y element is added to the elemental composition of the γ-Ni phase and the β-NiAl phase in the dual-phase MCrAlY bonding layer, and all the elemental compositions are homogenized to obtain an elemental composition of 63.91wt.%Ni, 28.84wt.%Cr, 6.25wt.%Al, and 1wt.%Y for the γ-Ni phase, and an elemental composition of 70.91wt.%Ni, 16.83wt.%Al, 11.26wt.%Cr, and 1wt.%Y for the β-NiAl phase; and then a γ-Ni phase target and a β-NiAl phase target are prepared by a vacuum melting method according to the elemental composition of the γ-Ni phase and the β-NiAl phase after the homogenization treatment, respectively;

[0079] Step 4: using the prepared γ-Ni phase target and β-NiAl phase target, depositing an MCrAlY coating on the surface of the pretreated substrate material to obtain an MCrAlY coating with a non-element concentration gradient;

[0080] The deposition time is 2h, the rotation angular velocity is 30 rpm, the current of the γ-Ni phase target is 140A, the current of the β-NiAl target is 150A, and the currents of the γ-Ni phase target and the β-NiAl phase target are set to be constant; during the preparation process, the argon gas flow rate is 180sccm, the vacuum degree in the furnace chamber is 1.0Pa, the preparation temperature is 400°C, and the bias voltage is 200V;

[0081] Step 5: The MCrAlY coating with non-element concentration gradient is heat treated under vacuum to prevent oxidation of the coating during the heat treatment. The heat treatment temperature is 1100°C and the time is 6 hours. Finally, a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient is obtained.

[0082] Figure 4 This is a SEM image of the cross section of the MCrAlY bonding layer of the dual-phase thermal barrier coating prepared in Example 2. Figure 4 It can be seen that the coating is a typical γ and β phase dual-phase coating, in which the dark part is the β phase and the light part is the γ phase; the elemental composition in the coating is tested by inductively coupled plasma atomic emission spectrometry analysis technology, and the specific components measured are: 22.98wt.% Cr, 10.03wt.% Al, 1.02wt.% Y, which are the same as the expected elemental composition of the coating, indicating that the preparation method of the present invention can accurately prepare a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient.

[0083] Example 3

[0084] A method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating specifically comprises the following steps:

[0085] Step 1: Pre-treat the surface of the nickel-based alloy;

[0086] The surface of the nickel-based alloy is ground, polished and cleaned in sequence to keep the surface of the nickel-based alloy clean and mirror-like;

[0087] Step 2: determining the elemental composition of the dual-phase MCrAlY bonding layer to be prepared, the elemental composition comprising: in atomic percentage, 22wt.% Cr, 12wt.% Al, 1wt.% Y, and the rest being Co; performing phase diagram calculation on the physical phases and elemental composition in the dual-phase MCrAlY bonding layer to obtain the elemental composition of the γ-Co phase and the β-CoAl phase in the dual-phase MCrAlY bonding layer;

[0088] Thermo-Calc software was used to calculate the phase diagram. The calculation mode was single-point calculation. The system was a thermodynamic and kinetic database of nickel-based alloys. The elements selected according to the proposed dual-phase MCrAlY bonding layer were Co, Cr, and Al. The Y element was not considered in the phase diagram calculation process. Parameter definition: the temperature input was 1050°C, the element composition input was the element composition of the MCrAlY bonding layer to be prepared after removing the Y element and homogenizing the other elements, i.e., 65.66wt.%Ni, 22.22wt.%Cr, and 12.12wt.%Al. The pressure was atmospheric pressure. Finally, the element composition of the γ-Co phase and the β-CoAl phase in the dual-phase MCrAlY bonding layer was obtained, i.e., the element composition of the γ-Co phase was 64.55wt.%Co, 30.26wt.%Cr, and 5.19wt.%Al, and the element composition of the β-CoAl phase was 67.89wt.%Ni, 20.87wt.%Al, and 11.24wt.%Cr.

[0089] Step 3: In step 2, 1wt% of Y element is added to the elemental composition of the γ-Co phase and the β-CoAl phase in the dual-phase MCrAlY bonding layer, and all the elemental compositions are homogenized to obtain an elemental composition of 63.9wt.%Ni, 29.96wt.%Cr, 5.14wt.%Al, and 1wt.%Y for the γ-Ni phase, and an elemental composition of 67.21wt.%Ni, 20.66wt.%Al, 11.13wt.%Cr, and 1wt.%Y for the β-NiAl phase; and then a γ-Co phase target and a β-CoAl phase target are prepared by a vacuum melting method according to the elemental composition of the γ-Co phase and the β-CoAl phase after the homogenization treatment, respectively;

[0090] Step 4: using the prepared γ-Ni phase target and β-NiAl phase target, depositing an MCrAlY coating on the surface of the pretreated substrate material to obtain an MCrAlY coating with a non-element concentration gradient;

[0091] The deposition time is 8 hours, the rotation angular velocity is 20 revolutions per minute, the current of the γ-Co phase target is 105A, the current of the β-CoAl phase target is 120A, and the currents of the γ-Co phase target and the β-CoAl phase target are set to remain constant; during the preparation process, the argon gas flow rate is 150 sccm, the vacuum degree in the furnace chamber is 0.8 Pa, the preparation temperature is 350° C., and the bias voltage is 160V;

[0092] Step 5: The MCrAlY coating with non-element concentration gradient is heat treated under vacuum to prevent oxidation of the coating during the heat treatment. The heat treatment temperature is 1050°C and the time is 4 hours. Finally, a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient is obtained.

[0093] Figure 5 This is a SEM image of the cross section of the CoCrAlY bonding layer of the dual-phase thermal barrier coating prepared in Example 2, wherein: Figure 5 (a) is at low resolution. Figure 5 (b) is at high resolution; Figure 5 It can be seen that the coating is a typical γ and β phase dual-phase coating, in which the dark part is the β phase and the light part is the γ phase; the elemental composition in the coating is tested by inductively coupled plasma atomic emission spectrometry analysis technology, and the specific components measured are: 22.01wt.% Cr, 11.95wt.% Al, 0.98wt.% Y, which are the same as the expected elemental composition of the coating, indicating that the preparation method of the present invention can accurately prepare a dual-phase thermal barrier coating MCrAlY bonding layer with non-element concentration gradient.

[0094] Example 4

[0095] The process and parameters of this embodiment are the same as those of Embodiment 1, except that: in step 4, the current of the γ-Ni phase target is constant at 100A, when the coating starts to be deposited, the current of the β-NiAl phase target is set to 80A, the total deposition time is 5h, the number of levels is 2, and the deposition time of each level is 2.5h; when the deposition time reaches 2.5h, the current of the β-NiAl target is set to 120A, and an MCrAlY bonding layer with an element concentration gradient is prepared, and finally an MCrAlY bonding layer of a dual-phase thermal barrier coating with an element concentration gradient is obtained.

[0096] Figure 6 This is a SEM image of the cross section of the MCrAlY bonding layer of the dual-phase thermal barrier coating prepared in Example 4. Figure 6It can be seen that the coating is a typical MCrAlY bonding layer with an Al element concentration gradient. Similarly, the coating is a typical γ and β phase dual-phase coating, in which the dark part is the β phase and the light part is the γ phase. From the microstructure of the coating cross section, it can be seen that the dark β phase content is low in the part close to the high-temperature alloy substrate, while the light γ phase content is high, indicating that the Al content in the coating close to the substrate material side is low, while the β phase content in the coating away from the substrate material side is increased, that is, the Al element content in the coating increases along the direction away from the substrate material, indicating that the preparation method of the present invention can accurately prepare a dual-phase thermal barrier coating MCrAlY bonding layer with an element concentration gradient.

[0097] Example 5

[0098] The process and parameters of this embodiment are the same as those of Embodiment 1, except that: in step 4, the current of the γ-Ni phase target is constant at 120A, when the coating begins to be deposited, the current of the β-NiAl phase target is set to 100A, the total deposition time is 3h, the number of grades is 6, and the deposition time of each grade is 0.5h; after depositing for 0.5h at a target current of 100A, the current of the β-NiAl phase target is set to 110A, and after continuing to deposit for 0.5h, the current of the β-NiAl phase target is set to 120A, and after continuing to deposit for 0.5h, the current of the β-NiAl phase target is set to 130A, and after continuing to deposit for 0.5h, the current of the β-NiAl phase target is set to 140A, and after continuing to deposit for 0.5h, the current of the β-NiAl phase target is set to 150A, and after continuing to deposit for 0.5h, the MCrAlY bonding layer with an element concentration gradient is prepared, and finally the MCrAlY bonding layer of a dual-phase thermal barrier coating with an element concentration gradient is obtained.

[0099] Figure 7 This is a SEM image of the cross section of the MCrAlY bonding layer of the dual-phase thermal barrier coating with element concentration gradient prepared in Example 5. Figure 7 It can be seen that the coating is a typical MCrAlY bonding layer with an Al element concentration gradient. Similarly, the coating is a typical γ and β phase dual-phase coating, in which the dark part is the β phase and the light part is the γ phase. From the microstructure of the coating cross section, it can be seen that the dark β phase content is low in the part close to the high-temperature alloy substrate, while the light γ phase content is high, indicating that the Al content in the coating close to the substrate material side is low, while the β phase content in the coating away from the substrate material side is increased, that is, the Al element content in the coating increases along the direction away from the substrate material, indicating that the preparation method of the present invention can accurately prepare a dual-phase thermal barrier coating MCrAlY bonding layer with an element concentration gradient.

Claims

1. A method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating, characterized in that: The steps include: Step 1: determining the elemental composition of the dual-phase MCrAlY bonding layer to be prepared, calculating the phase diagram of the physical phase and elemental composition in the dual-phase MCrAlY bonding layer, and obtaining the elemental composition of the γ phase and the β phase in the dual-phase MCrAlY bonding layer; Step 2: adding the Y element in the MCrAlY bonding layer to be prepared to the elemental components of the γ phase and the β phase in the dual-phase MCrAlY bonding layer at the same time, and homogenizing all the elemental components; then using a vacuum arc melting method to prepare a γ phase target and a β phase target according to the elemental components of the γ phase and β phase after the homogenization treatment; Step 3: using the prepared γ-phase target material and β-phase target material, and setting the target current, depositing the MCrAlY coating on the surface of the pretreated substrate material to obtain a non-element concentration gradient coating or an MCrAlY coating with an element concentration gradient; Step 4: heat-treating the non-element concentration gradient coating or the MCrAlY coating with an element concentration gradient under a vacuum state to obtain a non-element concentration gradient or an element concentration gradient dual-phase thermal barrier coating MCrAlY bonding layer.

2. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: The element composition of the dual-phase MCrAlY bonding layer to be prepared in step 1 includes: in atomic percentage, 10-30wt.% Cr, 6-17wt.% Al, 0.1-1wt.% Y, and the rest is Ni or Co elements.

3. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1 or 2, characterized in that: The element composition of the dual-phase MCrAlY bonding layer to be prepared in step 1 includes: in atomic percentage, 22-23wt.% Cr, 10-12wt.% Al, 0.5-1wt.% Y, and the rest is Ni or Co elements.

4. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: The step 1 uses Thermo-Calc software to calculate the phase diagram. The element types selected according to the dual-phase MCrAlY bonding layer to be prepared are Ni, Cr, Al or Co, Cr, Al. The Y element is not considered in the phase diagram calculation process; parameter definition: the temperature input is the heat treatment temperature of the substrate material, and the heat treatment temperature is 1000-1100° C. The element composition input is the element composition of the dual-phase MCrAlY bonding layer to be prepared after removing the Y element and the remaining elements are homogenized.

5. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: In the step 3, the prepared γ-phase target material and β-phase target material are set as a group of target materials, and a group of target materials are installed in the opposite direction of the substrate material, and the substrate material is rotated at a rotational angular velocity of 10-30 rpm to deposit the MCrAlY coating.

6. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: In step 3, the preparation process of the MCrAlY coating with non-element concentration gradient is as follows: The currents of the γ-phase target and the β-phase target are both 80-150A, and the currents of the γ-phase target and the β-phase target are set to remain constant; The preparation process of MCrAlY coating with element concentration gradient is as follows: The current of the γ-phase target material is 80-150A, and the current of the γ-phase target material is kept constant; the current of the β-phase target material is 80-150A, and the current of the β-phase target material is increased in a graded step-by-step manner, that is, at the initial moment, the target current is low, and at the end moment, the target current is high.

7. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 6, characterized in that: During the preparation of the MCrAlY coating with element concentration gradient, at the initial moment of coating deposition, the current of the β-phase target is 80-100A, and gradually increases to 120-150A in a step-by-step manner as the deposition time increases. The number of levels is 2-6, and the deposition time of each level is the total deposition time / number of levels.

8. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: Other parameters of the multi-arc ion plating in step 3 are: total deposition time of 2-8h, argon gas flow rate of 60-180sccm, vacuum degree in the furnace chamber of 0.1-1.0Pa, preparation temperature of 250-400°C, and bias voltage of 100-200V.

9. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: In step 3, the base material is a nickel-based alloy, and the pretreatment operation is: grinding, polishing and cleaning the surface of the nickel-based alloy in sequence to keep the surface of the nickel-based alloy clean and mirror-like.

10. The method for preparing a dual-phase thermal barrier coating MCrAlY bonding layer by multi-arc ion plating according to claim 1, characterized in that: In step 4, the heat treatment temperature is 1000-1100° C. and the time is 2-6 hours.

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