Alloy material with thermal barrier coating and preparation method thereof

Abstract

The invention provides an alloy material with a thermal barrier coating and a preparation method of the alloy material. The preparation method of the alloy material with the thermal barrier coating comprises the following steps: spraying ceramic matrix phase powder and a porous ceramic pore-forming agent on the surface of an alloy matrix with a bonding layer by adopting a plasma co-spraying process to form a porous ceramic layer so as to obtain the alloy material with the thermal barrier coating, the thermal barrier coating comprises the bonding layer and the porous ceramic layer; the bonding layer is positioned between the alloy matrix and the porous ceramic layer; the porous ceramic layer comprises a dense matrix phase and a porous cluster phase; wherein the injection content of the porous ceramic pore-forming agent is 8-35 g / min; the scanning speed of a spray gun in the spraying process is 450-650 mm / min; and the step height of a spray gun in the spraying process is 0.5-3.5 mm. According to the preparation method of the alloy material with the thermal barrier coating, the pore distribution and the pore structure in the thermal barrier coating can be regulated and controlled.

Description

Technical Field

[0001] The invention relates to the field of thermal barrier coatings, and in particular to an alloy material with a thermal barrier coating and a preparation method thereof. Background Art

[0002] Thermal barrier coatings (TBCs) are widely used on the surfaces of metallic hot end components of aircraft engines and gas turbines to provide the necessary thermal protection and thus produce higher thermal efficiency. Typically, TBCs are multilayer systems consisting of a top ceramic coating (TC) and an MCrAlY bonding layer (BC) on a high-temperature alloy substrate (SUB). As the top thermal barrier, the TC layer is the most critical part of the TBCs system. As an intermediate layer between the metal substrate and the surface layer, the BC layer is used to protect the components from oxidation and thermal fatigue damage. The TC layer is responsible for the main functions of the TBCs system, and the long-term reliability of TBCs performance is mainly affected by the original TC layer structure, which makes the regulation of the TC layer structure particularly important.

[0003] As a mature TBCs preparation technology, atmospheric plasma spraying (APS) is commonly used to deposit TBCs due to its low cost and high process flexibility. Micro defects in APS TBCs, mainly pores, are randomly dispersed inside the coating, which is usually related to the rapid solidification nature of the molten droplets. These pores are closely related to the thermal stress and thermal insulation ability of TBCs. A large number of researchers are committed to understanding the relationship between the microstructure and properties of APS TBCs. For example, APS TBCs deposited as high density show higher fracture stiffness and thermal conductivity. On the other hand, APS TBCs with highly porous structures show better compliance and lower thermal conductivity. Existing studies on APS TBCs believe that these TBCs with highly porous structures have a tendency to be durable. In most cases, these highly porous TBCs are considered to have the advantages of low sintering tendency, low thermal conductivity and high strain tolerance. In general, these pore structures contained in APS TBCs can be adjusted by changes in spraying parameters and feedstock powders. Therefore, researchers are increasingly preparing TBCs with ideal properties by adjusting spraying parameters. The researchers have conducted some experiments to adjust the pore structure of APS TBCs by controlling deposition parameters such as plasma power, spray distance, and spray angle. However, the limitation of these methods is that only the total porosity level of the coating can be adjusted. In addition, it is difficult to control the distribution of pores and their geometric morphology. The pores are still dispersed in the coating, and the geometry and distribution of pores are directly related to the mechanical and thermal insulation properties of TBCs.

[0004] Therefore, there is an urgent need for a new preparation method to facilitate the regulation of the pore microstructure and distribution in thermal barrier coatings of alloy materials, which will help optimize the thermal insulation properties and thermal shock life of thermal barrier coatings. Summary of the invention

[0005] In order to overcome the defects of the prior art that it is difficult to control the distribution and geometric morphology of pores in the thermal barrier coating during the preparation of the thermal barrier coating, resulting in poor thermal insulation performance and thermal shock life of the coating, the present invention provides an alloy material with a thermal barrier coating and a preparation method thereof. The present invention sprays a ceramic matrix phase powder and a porous ceramic pore former, and controls the injection content of the porous ceramic pore former and the scanning path of the plasma arc during the coating deposition process on the basis of a plasma co-spraying process to prepare a porous ceramic layer, which can achieve the purpose of regulating the pore distribution and pore structure in the thermal barrier coating, thereby making the thermal conductivity, hardness and elastic modulus of the prepared thermal barrier coating better.

[0006] A first aspect of the present invention provides a method for preparing an alloy material having a thermal barrier coating, the method comprising:

[0007] The ceramic matrix phase powder and the porous ceramic pore-forming agent are sprayed on the surface of the alloy matrix with the bonding layer by a plasma co-spraying process to form a porous ceramic layer, thereby obtaining the alloy material with the thermal barrier coating; the thermal barrier coating comprises the bonding layer and the porous ceramic layer; the bonding layer is located between the alloy matrix and the porous ceramic layer; the porous ceramic layer comprises a dense matrix phase and a porous cluster phase;

[0008] The injection content of the porous ceramic pore-forming agent is 8-35 g / min; the scanning rate of the spray gun during the spraying is 450-650 mm / min; and the step height of the spray gun during the spraying is 0.5-3.5 mm.

[0009] In some preferred embodiments, the particle size of the ceramic matrix phase powder is 10-50 μm.

[0010] In some preferred embodiments, the material of the ceramic matrix phase powder is selected from one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, magnesium oxide-stabilized zirconia, calcium oxide-stabilized zirconia, cerium oxide-stabilized zirconia, yttria-ytterbium oxide co-doped stabilized zirconia, lanthanum zirconate and gadolinium zirconate.

[0011] In some preferred embodiments, the porosity of the ceramic matrix phase powder is less than 1%. In some preferred embodiments, the internal pore size of the ceramic matrix phase powder is 100 nm-1 μm.

[0012] In some preferred embodiments, the particle size of the porous ceramic pore former is 30-80 μm.

[0013] In some preferred embodiments, the material of the porous ceramic pore former is selected from one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, magnesium oxide-stabilized zirconia, calcium oxide-stabilized zirconia, cerium oxide-stabilized zirconia, yttria-ytterbium oxide co-doped stabilized zirconia, lanthanum zirconate and gadolinium zirconate.

[0014] In some preferred embodiments, the porosity of the porous ceramic pore former is ≥10%. In some preferred embodiments, the internal pore size of the porous ceramic pore former is 1 μm-10 μm.

[0015] In some preferred embodiments, the porous cluster phase is randomly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 8-18 g / min, the scanning rate of the spray gun in the spraying is 450-550 mm / min, and the step height of the spray gun in the spraying is 2.5-3.5 mm. More preferably, the circumference of the porous cluster phase is 62-70 μm. More preferably, the aspect ratio of the porous cluster phase is 1.2-2. More preferably, the horizontal distance between the porous cluster phases is 22-52 μm.

[0016] In some preferred embodiments, the porous cluster phase is orderly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 19-28 g / min, the scanning rate of the spray gun in the spraying is 551-650 mm / min, and the step height of the spray gun in the spraying is 1.5-2.4 mm. More preferably, the circumference of the porous cluster phase is 80-90 μm. More preferably, the aspect ratio of the porous cluster phase is 1.5-2.5. More preferably, the horizontal distance between the porous cluster phases is 35-55 μm.

[0017] In some preferred embodiments, the porous cluster phase is regularly linearly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 29-35 g / min, the scanning rate of the spray gun in the spraying is 551-650 mm / min, and the step height of the spray gun in the spraying is 0.5-1.4 mm. More preferably, the circumference of the porous cluster phase is 145-155 μm. More preferably, the aspect ratio of the porous cluster phase is 2.5-3.5. More preferably, the horizontal distance between the porous cluster phases is 45-58 μm.

[0018] In some preferred embodiments, in the plasma co-spraying process, the ceramic matrix phase powder and the porous ceramic pore-forming agent are sprayed onto the surface of the substrate by a double powder feeding coaxial radial conveying method to form a porous ceramic layer.

[0019] In some preferred embodiments, in the plasma co-spraying process, the injection content of the ceramic matrix phase powder is 2-15 g / min.

[0020] In some preferred embodiments, in the plasma co-spraying process, the spraying distance is 80-150 mm.

[0021] In some preferred embodiments, the injection content of the porous ceramic pore former is 15-30 g / min; the scanning rate of the spray gun during the spraying is 550-600 mm / min; and the step height of the spray gun during the spraying is 1-2 mm.

[0022] In some preferred embodiments, the porous ceramic layer has a thickness of 20-3000 μm.

[0023] In some preferred embodiments, the porosity of the porous ceramic layer is 15%-18%.

[0024] In some preferred embodiments, the alloy matrix is ​​made of a nickel-based or cobalt-based high-temperature alloy material.

[0025] In some preferred embodiments, the surface roughness Ra of the alloy substrate is 5-8 μm.

[0026] In some preferred embodiments, the bonding layer is made of MCrAlY alloy, wherein M is one or two elements selected from Ni and Co.

[0027] In some preferred embodiments, the thickness of the adhesive layer is 140-160 μm.

[0028] In some preferred embodiments, the circumference of the porous cluster phase is 62-155 μm.

[0029] In some preferred embodiments, the aspect ratio of the porous cluster phase is 1.2-3.5.

[0030] In some preferred embodiments, the horizontal distance between the porous cluster phases is 22-58 μm.

[0031] The second aspect of the present invention provides an alloy material with a thermal barrier coating, which is prepared by the preparation method of the alloy material with a thermal barrier coating as described in any embodiment of the present invention. The thermal barrier coating comprises the bonding layer and the porous ceramic layer; the bonding layer is located between the alloy matrix and the porous ceramic layer; the porous ceramic layer comprises a dense matrix phase and a porous cluster phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the pore structure control strategy and the porous ceramic layer preparation method of the present invention.

[0033] Figure 2 This is a cross-sectional microstructure diagram of the porous ceramic layer prepared in Example 1.

[0034] Figure 3 This is a cross-sectional microstructure diagram of the porous ceramic layer prepared in Example 2.

[0035] Figure 4 This is a cross-sectional microstructure diagram of the porous ceramic layer prepared in Example 3.

[0036] Figure 5 This is a comparison chart of the overall porosity of the porous ceramic layers prepared in Examples 1-3.

[0037] Figure 6 This is a comparison chart of the thermal conductivities of the porous ceramic layers prepared in Examples 1-3.

[0038] Figure 7 The microhardness and elastic modulus comparison chart of the porous ceramic layers prepared in Examples 1-3. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0040] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0041] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0042] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0043] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0044] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0045] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0046] Different from the existing research that prepares thermal barrier coatings of alloy materials by controlling deposition parameters, the researchers of the present invention found that by adding porous ceramic pore formers into the coating by plasma co-spraying to create a pore structure, and simultaneously regulating the injection content of the pore former and the scanning path of the plasma flame arc during the coating deposition process, it is possible to achieve the effect of regulating the pore geometry and distribution in the thermal barrier coating, thereby effectively improving the thermodynamic properties of the thermal barrier coating.

[0047] The material of the ceramic matrix phase powder suitable for the present invention can be a ceramic material conventionally used in the art for preparing thermal barrier coatings, including but not limited to at least one selected from yttria-stabilized zirconia (YSZ for short), scandium oxide-stabilized zirconia, magnesium oxide-stabilized zirconia, calcium oxide-stabilized zirconia, cerium oxide-stabilized zirconia, yttria-ytterbium oxide co-doped stabilized zirconia, lanthanum zirconate and gadolinium zirconate.

[0048] In the present invention, the ceramic matrix phase powder forms a dense matrix phase. Conventional ceramic matrix phase powders include commercial dense spherical thermal spray powders. The internal pore size of the ceramic matrix phase powder is preferably submicron (100nm-1μm). The porosity of the ceramic matrix phase powder is preferably <1%.

[0049] In the present invention, the porous ceramic pore former has a porous structure, and the internal pore size is preferably micrometer-level (1 μm-10 μm). The porosity of the porous ceramic pore former is preferably ≥10%. In some preferred embodiments, the porous ceramic pore former of the present invention is prepared by agglomerating and sintering a primary ceramic raw material powder. The size of the selected primary ceramic raw material powder is preferably 1-5 μm, for example, 2 μm.

[0050] The material of the porous ceramic pore-forming agent suitable for the present invention can be one or more of yttria-stabilized zirconia, scandium oxide-stabilized zirconia, magnesium oxide-stabilized zirconia, calcium oxide-stabilized zirconia, cerium oxide-stabilized zirconia, yttria-ytterbium oxide co-doped stabilized zirconia, lanthanum zirconate and gadolinium zirconate materials. In some preferred embodiments, before depositing the porous ceramic layer, the ceramic matrix phase powder and the porous ceramic pore-forming agent are first sieved and dried. The particle size of the ceramic matrix phase powder after sieving is preferably 10-50 μm. The particle size of the porous ceramic pore-forming agent after sieving is preferably 30-80 μm. The drying method can adopt the conventional drying method in the art, such as vacuum drying.

[0051] The researchers of the present invention found in their studies that there is a correlation between the injection content of the porous ceramic pore-forming agent and the scanning path of the plasma flame arc during the coating deposition process, and the geometric morphology and distribution of the porous cluster phase and pores in the coating. By controlling the injection content of the porous ceramic pore-forming agent as well as the scanning rate and step height of the spray gun in a linked manner, the geometric morphology and distribution of the porous cluster phase in the coating can be improved, thereby achieving the goal of regulating the pore structure and distribution in the coating. The prepared coating shows an obvious composite structure, forming a porous cluster phase in addition to the dense matrix phase, and the porous cluster phases in these coatings contribute the main pore content to the coating. Among them, the dense matrix phase melts well, and the porous cluster phase contains a large number of pores. The control strategy and preparation method of the pore structure of the present invention are as follows Figure 1 As shown, the step height is Figure 1 As shown in the label, it can also be called the longitudinal step length.

[0052] The injection content of the porous ceramic pore former is 8-35 g / min, preferably 15-30 g / min, for example, 10 g / min, 12 g / min, 15 g / min, 18 g / min, 22 g / min, 25 g / min, 28 g / min, 30 g / min, 32 g / min, 34 g / min.

[0053] The scanning rate of the spray gun is 450-650 mm / min, preferably 550-650 mm / min, for example 520 mm / min, 550 mm / min, 560 mm / min, 580 mm / min, 600 mm / min, 620 mm / min, 640 mm / min.

[0054] The step height of the spray gun is 0.5-3.5 mm, preferably 1-2 mm, for example 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.3 mm.

[0055] In some preferred embodiments, the porous cluster phase is randomly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 8-18 g / min, the scanning rate of the spray gun during spraying is 450-550 mm / min, and the step height of the spray gun during spraying is 2.5-3.5 mm. Preferably, in the formed porous ceramic layer, the circumference of the porous cluster phase is 62-70 μm, the aspect ratio of the porous cluster phase is 1.2-2, and the horizontal distance between the porous cluster phases is 22-52 μm.

[0056] In some specific embodiments, the porous cluster phase is randomly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 10 g / min, the scanning rate of the spray gun is 500 mm / min, and the step height of the spray gun is 3 mm. The porous cluster phase is mainly concentrated at about 65 μm, the aspect ratio is mainly concentrated at about 1.5, and the horizontal distance between the porous cluster phases is mainly concentrated at 25-50 μm.

[0057] In some preferred embodiments, the porous cluster phase is orderly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 19-28 g / min, the scanning rate of the spray gun during spraying is 551-650 mm / min, and the step height of the spray gun during spraying is 1.5-2.4 mm. Preferably, in the formed porous ceramic layer, the circumference of the porous cluster phase is 80-90 μm, the aspect ratio of the porous cluster phase is 1.5-2.5, and the horizontal distance between the porous cluster phases is 35-55 μm.

[0058] In some specific embodiments, the porous cluster phase is orderly distributed in the porous ceramic layer, the injection content of the porous ceramic pore former is 25 g / min, the scanning rate of the spray gun is 600 mm / min, and the step height of the spray gun is 2 mm. The circumference of the porous cluster phase is mainly concentrated at about 85 μm, the aspect ratio is mainly concentrated at about 2, and the horizontal distance between the porous cluster phases is mainly concentrated at 40-50 μm.

[0059] In some preferred embodiments, the porous cluster phase is regularly distributed linearly in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 29-35 g / min, the scanning rate of the spray gun during spraying is 551-650 mm / min, and the step height of the spray gun during spraying is 0.5-1.4 mm. Preferably, in the formed porous ceramic layer, the circumference of the porous cluster phase is 145-155 μm, the aspect ratio of the porous cluster phase is 2.5-3.5, and the horizontal distance between the porous cluster phases is 45-58 μm.

[0060] In some specific embodiments, the porous cluster phase is regularly distributed linearly in the porous ceramic layer, the injection content of the porous ceramic pore former is 30 g / min, the scanning rate of the spray gun is 600 mm / min, and the step height of the spray gun is 1 mm. The circumference of the porous cluster phase is mainly concentrated around 150 μm, the aspect ratio is mainly concentrated around 3, and the horizontal distance between the porous cluster phases is mainly concentrated around 50-55 μm.

[0061] In some preferred embodiments, the injection content of the ceramic matrix phase powder is preferably 2-15 g / min, for example, 5 g / min, 8 g / min, 10 g / min, 12 g / min, 14 g / min. The spraying distance is preferably 80-150 mm, for example, 8 mm, 10 mm, 120 mm, 140 mm. Other deposition parameters of the spraying can be adjusted according to the accumulated experience of conventional spraying coating preparation in the prior art.

[0062] In some preferred embodiments, the circumference of the porous cluster phase is 62-155 μm, preferably 80-155 μm, for example 63 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 152 μm.

[0063] In some preferred embodiments, the aspect ratio of the porous cluster phase is 1.2-3.5, preferably 1.5-3.5, for example 1.3, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.4.

[0064] In some preferred embodiments, the horizontal distance between the porous cluster phases is 22-58 μm, preferably 35-58 μm, for example 23 μm, 25 μm, 28 μm, 30 μm, 35 μm, 38 μm, 40 μm, 42 μm, 45 μm, 48 μm, 50 μm, 52 μm, 55 μm, 57 μm.

[0065] In some preferred embodiments, the thickness of the porous ceramic layer is 20-3000 μm, for example, 50 μm, 100 μm, 200 μm, 500 μm, 700 μm, 880 μm, 900 μm, 960 μm, 1200 μm, 1800 μm, 2000 μm, 2500 μm, 2800 μm.

[0066] In some preferred embodiments, the porosity of the porous ceramic layer is 15%-18%, for example, 15%, 16%, 17%, or 18%.

[0067] The material of the alloy substrate applicable to the present invention can be selected from the alloy materials conventionally used in the art for preparing thermal barrier coatings, such as nickel-based or cobalt-based high-temperature alloy materials. The surface roughness Ra of the alloy substrate is preferably 5-8 μm.

[0068] The material of the bonding layer suitable for the present invention can be selected from the bonding layer materials conventionally used in the art for preparing thermal barrier coatings, such as MCrAlY alloy, wherein M is one or two elements selected from Ni and Co. The thickness of the bonding layer is preferably 140-160 μm, such as 142 μm, 145 μm, 150 μm, 155 μm, or 158 μm.

[0069] In some preferred embodiments, the method of spraying using dual powder feeding coaxial radial transmission is to use a double-drum powder feeder to inject ceramic matrix phase powder and porous ceramic pore-forming agent into the high-temperature end of the center of the plasma flame arc and the low-temperature end of the tail end through a plasma co-spraying process to spray the surface of the alloy substrate with a bonding layer to deposit and form a porous ceramic layer.

[0070] In some preferred embodiments, the method for preparing the alloy material having a thermal barrier coating of the present invention comprises the following steps:

[0071] Step (1): preparing a bonding layer on the surface of the alloy substrate;

[0072] Step (2): using a method as described in any of the aforementioned embodiments herein, spraying a ceramic matrix phase powder and a porous ceramic pore-forming agent onto the surface of an alloy substrate having a bonding layer by a plasma co-spraying process to form a porous ceramic layer, thereby obtaining the alloy material having a thermal barrier coating.

[0073] In some preferred embodiments, before preparing the bonding layer on the surface of the alloy substrate, the alloy substrate is first pretreated, and the pretreatment steps may include: surface roughening treatment, ultrasonic cleaning and drying of the surface of the alloy substrate.

[0074] The abrasive used for the surface roughening treatment can be selected from the raw materials conventionally used in the art for surface treatment of alloy substrates, such as gravel. The gravel is preferably corundum gravel. The mesh range of the abrasive is preferably 40-80 mesh. After the surface roughening treatment, the roughness Ra of the substrate surface obtained is preferably 5-8 μm. In some specific embodiments, the surface roughening treatment is performed by sandblasting the surface of the alloy substrate.

[0075] The cleaning agent used in ultrasonic cleaning can be a cleaning agent conventionally used in the art for cleaning alloy substrates, such as acetone and alcohol. The surface drying treatment is generally performed at 100-140°C, such as 110°C, 120°C or 130°C.

[0076] In some preferred embodiments, before preparing the bonding layer on the surface of the alloy substrate, the bonding layer powder is subjected to vacuum drying. The vacuum drying temperature may be 100-140° C., for example, 110° C., 120° C., 130° C. The vacuum drying time may be 3-7 hours, for example, 4 hours, 5 hours, 6 hours.

[0077] The bonding layer may be prepared on the surface of the alloy substrate in a conventional manner in the art, such as spraying bonding layer powder onto the surface of the alloy substrate using a plasma spraying process to form the bonding layer. In some preferred embodiments, the bonding layer powder is injected into the center of a high-energy plasma beam and sprayed onto the surface of the alloy substrate using a plasma spraying process to form the bonding layer.

[0078] Wherein, the injection content of the bonding layer powder is preferably 8-12g / min, for example, 9g / min, 10g / min, 11g / min. The spraying distance is preferably 100-140mm, for example, 110mm, 120mm, 130mm. The bonding layer powder injection gas pressure is preferably 0.2-0.4Mpa, for example, 0.25Mpa, 0.3Mpa, 0.35Mpa. The main gas in the spraying can be selected from argon. The main gas flow rate is preferably 50-70slpm, for example, 55slpm, 60slpm, 65slpm. The auxiliary gas can be selected from hydrogen. The auxiliary gas flow rate is preferably 3-8slpm, for example, 4slpm, 5slpm, 6slpm, 7slpm. The current in the preparation process can be 300-600A, for example, 400A, 450A, 500A, 550A. The power can be 30-40KW, for example, 32KW, 35KW, 38KW. After the plasma beam accelerates and melts the bonding layer powder, a dense bonding layer with a thickness of 140-160μm is finally formed on the surface of the alloy matrix. The thickness of the bonding layer can be 142μm, 145μm, 148μm, 150μm, 152μm, 155μm or 158μm.

[0079] In some specific embodiments, the bonding layer powder injection content is 10g / min; the main gas during the preparation process is argon, and the flow rate is maintained at 60slpm; the auxiliary gas is hydrogen, and the flow rate is maintained at 5slpm; the current is 500A, and the power is 35KW; the spraying distance during the bonding layer deposition process is 120mm, and the powder injection gas pressure is 0.3MPa. After the plasma beam accelerates and melts the bonding layer powder, a dense bonding layer with a thickness of about 150μm is finally formed on the substrate surface.

[0080] The present invention provides an alloy material with a thermal barrier coating, which is prepared by the method for preparing an alloy material with a thermal barrier coating as described in any embodiment of the present invention.

[0081] The present invention has the following beneficial effects:

[0082] The present invention sprays ceramic matrix phase powder and porous ceramic pore former by adopting plasma co-spraying process, and controls the injection content of porous ceramic pore former and the scanning path (spray gun scanning rate and step height) of plasma flame arc in the coating deposition process on the basis of plasma co-spraying process to prepare porous ceramic layer on the surface of alloy substrate with bonding layer, so as to achieve the effect of regulating pore distribution and pore structure in coating; with the increase of pore distribution regularity and pore flattening degree, the thermal conductivity of thermal barrier coating can be gradually reduced; with the change of pore structure, the hardness of thermal barrier coating is reduced and the elastic modulus performance is improved, so as to effectively improve the thermodynamic properties of thermal barrier coating as a whole. The preparation method of the present invention has excellent process flexibility, and can efficiently and conveniently achieve the purpose of artificially regulating the pore structure in thermal barrier coating system, so as to optimize the overall structure of coating. The thermal barrier coating of the present invention can be widely used in the surface protection of hot end components in aerospace, aviation, and gas turbine, so as to improve the overall service performance of components.

[0083] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0084] The sources and specifications of the raw materials used in the examples are as follows:

[0085] Nickel-based high-temperature alloy material: IN-738, Beijing Runhang Technology Co., Ltd.

[0086] Ceramic matrix phase powder: YSZ ceramic powder (brand metco 204b-ns), Oerlikon Metco Surface Technology Co., Ltd., Shanghai, porosity <1%, the internal pore size of the powder is in the range of 100nm-1μm.

[0087] Porous ceramic pore former: Customized MAYSZ porous agglomerated ceramic powder, Anhui Yingrui Youcai Co., Ltd., Wuhu. The specific preparation method is: YSZ primary powder particles with a size of 2 μm are used for preparation by agglomeration-sintering method. The prepared MAYSZ porous agglomerated ceramic powder contains a large number of micron-sized pores, the pore size of the powder is 1 μm-10 μm, and the porosity is 10%.

[0088] The testing method of material performance parameters in the embodiment is as follows:

[0089] (1) Thickness of bonding layer and porous ceramic layer: The coating thickness is measured by metallographic method on production parts or test pieces. The test pieces are randomly selected and the thickness is above 1.52 mm. The test pieces are measured at 3 different locations and the accuracy is 0.01 mm.

[0090] (2) Perimeter, aspect ratio, and horizontal distance of the porous cluster phase: Five parallel samples were randomly selected. After standard metallographic treatment, the samples were placed under a scanning electron microscope (SEM, Hitachi S3400N, Japan) to observe their cross-sectional microstructure and measure the perimeter, aspect ratio, and horizontal distance of the porous cluster phase. Five different positions of each sample were randomly selected at a magnification of 200 times for measurement and statistics.

[0091] (3) Porosity: Three parallel samples were randomly selected from each group of samples, and the coating porosity was measured using the image method. During the test, five different locations were randomly selected for measurement using a scanning electron image at a magnification of 200 times. Finally, the highest and lowest values ​​in the statistical results were removed, and the remaining average was taken as the coating porosity, and the error was statistically calculated.

[0092] (4) Thermal conductivity: The thermal conductivity of the coating sample with a size of 1 mm × 1 mm was tested by laser flash method using a thermal conductivity tester (LFA 427, NETZSCH, Bavaria, Germany). Each temperature point was tested three times to reduce the error.

[0093] (5) Hardness and elastic modulus: The microhardness (H) and elastic modulus (E) of the coating on the polished cross section of the sample were measured using an indentation test system (HX-1000TM / LCD, Shanghai Taiming Optical Instrument Co., Ltd., China) under a load of 300 gf and a holding time of 20 seconds. At least 15 random locations in each coating sample were used for indentation measurement. The elastic modulus of the coating can be determined according to the following formula:

[0094]

[0095] Wherein, α=0.45 is the constant of the Knoop indenter; H is the hardness; b′ / a′ is the ratio of the indentation lengths of the small diagonal and the large diagonal; and for the geometry of the Knoop indenter, b / a is 1 / 7.11.

[0096] Example 1

[0097] This embodiment prepares an alloy material having a porous thermal barrier coating with disorderly distributed pores. The specific preparation steps are as follows:

[0098] S1. Surface roughening, ultrasonic cleaning and drying of the alloy substrate:

[0099] Specifically, the polished nickel-based high-temperature alloy material is roughened by using abrasive corundum grit; the mesh size of the selected corundum grit is 40-80 mesh, and the surface roughness Ra of the obtained alloy substrate is 5 μm. Then, the alloy substrate after sandblasting is cleaned by acetone and alcohol ultrasonic surface cleaning in turn, and the surface is dried at 120°C.

[0100] S2. Preparing a bonding layer on the surface of the alloy substrate:

[0101] S21. The NiCrAlY bonding layer powder (69.2wt% Ni-21% Cr-9% Al-0.8% Y, AMDRY 962, Oerlikon Metco Surface Technology Co., Ltd., Shanghai) was vacuum dried at a temperature of 120° C. for 5 hours.

[0102] S22. Inject the treated bonding layer powder into the center of the high-energy plasma beam to prepare the bonding layer. The bonding layer powder injection content is 10g / min. During the preparation process, the main gas is argon, and the flow rate is maintained at 60slpm; the auxiliary gas is hydrogen, and the flow rate is maintained at 5slpm; the current is 500A, and the power is 35KW. During the bonding layer deposition process, the spraying distance is 120mm, and the powder injection gas pressure is 0.3MPa. After the plasma beam accelerates and melts the bonding layer powder, a dense bonding layer with a thickness of about 150μm is finally formed on the surface of the alloy matrix.

[0103] S3. Spraying the ceramic matrix phase powder and the porous ceramic pore-forming agent on the surface of the alloy substrate having the bonding layer by plasma co-spraying process to form a porous ceramic layer, thereby obtaining an alloy material having a thermal barrier coating:

[0104] S31. Screening the ceramic matrix phase powder and the porous ceramic pore-forming agent to obtain ceramic matrix phase powder with a particle size of 10-50 μm and porous ceramic pore-forming agent with a particle size of 30-80 μm, respectively, and then vacuum drying the two screened powders.

[0105] S32. Using a double-drum powder feeder, ceramic matrix phase powder and porous ceramic pore-forming agent are respectively injected into the high-temperature end of the center and the low-temperature end of the tail of the plasma flame arc through a plasma co-spraying process, and sprayed on the opposite surface of the bonding layer away from the alloy matrix to form a porous ceramic layer.

[0106] During the deposition of the porous ceramic layer, the injection content of the porous ceramic pore former, the scanning speed of the spray gun, and the step height are jointly regulated. Among them, the injection content of the porous ceramic pore former is 10 g / min; the scanning speed of the spray gun is 500 mm / min; the step height of the spray gun is 3 mm. Other parameter settings are as follows: the injection content of the ceramic matrix phase powder during the deposition process is 8 g / min; the spraying distance is 80 mm; the injection gas pressure is 0.2 MPa; the main gas is Ar, and the flow rate is maintained at 35 slpm; the auxiliary gas is H2, and the flow rate is maintained at 8 slpm; the spraying current is 500 A, and the power is 37 KW.

[0107] The thickness of the prepared porous ceramic layer is 960 μm.

[0108] Figure 2 It is the cross-sectional microstructural diagram of the porous ceramic layer prepared in Example 1. As Figure 2 shown, the porous ceramic layer shows an obvious composite structure, including a dense matrix phase and a porous cluster phase. Among them, the melting condition of the dense matrix phase is good, and a large number of pores are included in the porous cluster phase; the distribution of the porous cluster phase and pores in the porous ceramic layer is dispersed and disordered. The perimeter of the porous cluster phase is mainly concentrated around 65 μm, the aspect ratio is mainly concentrated around 1.5, and the horizontal distance between the porous cluster phases is mainly concentrated between 25 - 50 μm.

[0109] Example 2

[0110] In this example, an alloy material with a thermal barrier coating having pores distributed in a moderately ordered manner is prepared. The difference between Example 2 and Example 1 is only that in step S3, the injection content of the porous ceramic pore former is 25 g / min; the scanning speed of the spray gun is 600 mm / min; the step height of the spray gun is 2 mm; the rest of the steps are the same as those in Example 1. The thickness of the prepared porous ceramic layer is 880 μm.

[0111] Figure 3 It is the cross-sectional microstructural diagram of the porous ceramic layer prepared in Example 2. As Figure 3 shown, compared with the cross-sectional microstructure of the porous ceramic layer in Example 1, the degree of order of the pore distribution in the porous ceramic layer in Example 2 is significantly improved. The perimeter of the porous cluster phase is mainly concentrated around 85 μm, the aspect ratio is mainly concentrated around 2, and the horizontal distance between the porous cluster phases is mainly concentrated between 40 - 50 μm.

[0112] Example 3

[0113] This embodiment prepares an alloy material having a thermal barrier coating with regularly linearly distributed pores. The only difference between Example 3 and Example 1 is that in step S3, the injection content of the porous ceramic pore-forming agent is 30 g / min; the scanning rate of the spray gun is 600 mm / min; the step height of the spray gun is 1 mm; and the remaining steps are the same as in Example 1. The thickness of the prepared porous ceramic layer is 900 μm.

[0114] Figure 4 This is a cross-sectional microstructure diagram of the porous ceramic layer prepared in Example 3. Figure 4 As shown, the porous cluster phase and pore structure in the porous ceramic layer of Example 3 are regularly linearly distributed. The circumference of the porous cluster phase is mainly concentrated around 150 μm, the aspect ratio is mainly concentrated around 3, and the horizontal distance between the porous cluster phases is mainly concentrated around 50-55 μm.

[0115] Figure 5 1 is a comparison chart of the porosity of the porous ceramic layers obtained in Examples 1-3. Figure 5 As shown, the porosity of the porous ceramic layers prepared in Examples 1-3 is not much different, and is distributed between about 15% and 18%.

[0116] The thermal conductivity of the porous ceramic layer prepared in Examples 1-3 within the range of 200-1000°C is as follows: Figure 6 As shown. Figure 6 It can be seen that the thermal diffusion coefficients of the porous ceramic layers of Examples 1-3 gradually decrease with the increase of the test temperature. As the pore distribution regularity and the degree of pore flattening increase, the thermal conductivity of the porous ceramic layers of Examples 1-3 becomes lower, among which the porous ceramic layer of Example 3 has the lowest thermal conductivity. Moreover, according to the test results of thermal conductivity, it can be shown that the pore structure and distribution of the porous ceramic layer can be effectively regulated by the method provided by the present invention, so as to effectively regulate the thermal conductivity of the porous ceramic layer.

[0117] The hardness and elastic modulus properties of the porous ceramic layer prepared in Examples 1-3 are as follows: Figure 7 As shown. Figure 7 It can be seen that the hardness and elastic modulus of the porous ceramic layer in Examples 1 to 3 change significantly with the change of the pore structure, and the evolution of the hardness and elastic modulus shows the same trend. The porous ceramic layer provided by Example 2 has the lowest hardness and elastic modulus values.

Claims

1. A method for preparing an alloy material having a thermal barrier coating, It is characterized in that The method comprises: The ceramic matrix phase powder and the porous ceramic pore-forming agent are sprayed on the surface of the alloy matrix with the bonding layer by a plasma co-spraying process to form a porous ceramic layer, thereby obtaining the alloy material with the thermal barrier coating; the thermal barrier coating comprises the bonding layer and the porous ceramic layer; the bonding layer is located between the alloy matrix and the porous ceramic layer; the porous ceramic layer comprises a dense matrix phase and a porous cluster phase; The injection content of the porous ceramic pore-forming agent is 8-35 g / min; the scanning rate of the spray gun during the spraying is 450-650 mm / min; and the step height of the spray gun during the spraying is 0.5-3.5 mm.

2. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The method has one or more of the following features: The particle size of the ceramic matrix phase powder is 10-50 μm; The material of the ceramic matrix phase powder is one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, magnesia-stabilized zirconia, calcia-stabilized zirconia, cerium-stabilized zirconia, yttria-ytterbium-oxide co-doped stabilized zirconia, lanthanum zirconate and gadolinium zirconate; The porosity of the ceramic matrix phase powder is less than 1%; The internal pore size of the ceramic matrix phase powder is 100nm-1μm; The particle size of the porous ceramic pore-forming agent is 30-80 μm; The porous ceramic pore former is made of one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, magnesia-stabilized zirconia, calcia-stabilized zirconia, cerium-stabilized zirconia, yttria-ytterbium-oxide co-doped stabilized zirconia, lanthanum zirconate and gadolinium zirconate; The porosity of the porous ceramic pore-forming agent is ≥10%; The internal pore size of the porous ceramic pore former is 1 μm-10 μm.

3. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The porous cluster phase is randomly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 8-18 g / min, the scanning rate of the spray gun during the spraying is 450-550 mm / min, and the step height of the spray gun during the spraying is 2.5-3.5 mm; Preferably, the circumference of the porous cluster phase is 62-70 μm, the aspect ratio of the porous cluster phase is 1.2-2, and the horizontal distance between the porous cluster phases is 22-52 μm.

4. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The porous cluster phase is orderly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 19-28 g / min, the scanning rate of the spray gun during the spraying is 551-650 mm / min, and the step height of the spray gun during the spraying is 1.5-2.4 mm; Preferably, the circumference of the porous cluster phase is 80-90 μm, the aspect ratio of the porous cluster phase is 1.5-2.5, and the horizontal distance between the porous cluster phases is 35-55 μm.

5. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The porous cluster phase is regularly and linearly distributed in the porous ceramic layer, the injection content of the porous ceramic pore-forming agent is 29-35 g / min, the scanning rate of the spray gun during the spraying is 551-650 mm / min, and the step height of the spray gun during the spraying is 0.5-1.4 mm; Preferably, the circumference of the porous cluster phase is 145-155 μm, the aspect ratio of the porous cluster phase is 2.5-3.5, and the horizontal distance between the porous cluster phases is 45-58 μm.

6. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The method has one or more of the following features: In the plasma co-spraying process, the ceramic matrix phase powder and the porous ceramic pore-forming agent are sprayed onto the surface of the substrate to form a porous ceramic layer by using a double powder feeding coaxial radial transmission method; In the plasma co-spraying process, the injection content of the ceramic matrix phase powder is 2-15 g / min; In the plasma co-spraying process, the spraying distance is 80-150 mm.

7. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The injection content of the porous ceramic pore-forming agent is 15-30 g / min; the scanning rate of the spray gun during the spraying is 550-600 mm / min; and the step height of the spray gun during the spraying is 1-2 mm.

8. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The method has one or more of the following features: The thickness of the porous ceramic layer is 20-3000 μm; The porosity of the porous ceramic layer is 15%-18%; The alloy matrix is ​​made of nickel-based or cobalt-based high-temperature alloy material; The surface roughness Ra of the alloy substrate is 5-8 μm; The material of the bonding layer is MCrAlY alloy, wherein M is one or two elements selected from Ni and Co; The thickness of the bonding layer is 140-160 μm.

9. The method for preparing the alloy material with thermal barrier coating according to claim 1, It is characterized in that The method has one or more of the following features: The circumference of the porous cluster phase is 62-155 μm; The aspect ratio of the porous cluster phase is 1.2-3.5; The horizontal distance between the porous cluster phases is 22-58 μm.

10. An alloy material having a thermal barrier coating, It is characterized in that The alloy material is prepared by the method for preparing an alloy material with a thermal barrier coating as described in any one of claims 1 to 9.

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