A method for preparing a fiber-toughened vertical crack composite structure coating

Abstract

The application discloses a preparation method of a fiber toughened vertical crack composite structure coating, and comprises the following steps: mixing high-aspect-ratio ZrO2 fibers with spherical ceramic nano-powder to obtain a mixed product; adding the mixed product into a solvent, and then adding a dispersant to prepare a suspension; ultrasonic dispersing the suspension, and then performing ball milling treatment; atomizing the suspension through a pressure type two-fluid air centrifugal atomizer; and melting and accelerating the atomized suspension to impact a metal substrate surface under the action of a wide-speed-range high-energy plasma spraying heat source, so as to obtain the fiber toughened vertical crack composite structure coating. In the process of water cooling and thermal shock cycle, the coating generates cracks, and the cracks are deflected or terminated when the cracks expand to the fibers, so that the energy required for crack expansion is increased. Therefore, the fibers can improve the mechanical properties and service life of the coating, and the preparation period is short, the process is simple, the preparation is easy to control, and the coating can be mass-produced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coating preparation, and particularly relates to a preparation method of a fiber-toughened vertical crack composite structure coating. BACKGROUND

[0002] A thermal barrier coating is a functional coating with thermal protection and thermal blocking effects, which is coated on the surface of a metal substrate to reduce the surface temperature of the substrate and ensure normal service in a high-temperature environment. Ceramic coating materials in the combustion chamber of an aero-engine inevitably fail in the application process due to the harsh service environment. The reasons for failure are numerous, but the final failure form is generally the formation, expansion, connection and formation of destructive cracks of ceramic layer cracks, and then peeling. Therefore, the low fracture toughness and weak bonding strength of the ceramic layer are the most fundamental reasons for coating failure.

[0003] Fibers are applied to the toughening of ceramic coatings through effects such as connection and extraction. The addition of fibers can significantly improve the fracture toughness and service life of the coating, effectively solving the problem of coating cracking and crack propagation caused by excessive brittleness of the coating. At the same time, the supersonic suspension plasma spraying technology eliminates the complex and tedious granulation process, simplifies the preparation process route of nano-structured coatings, and solves the problems of powder aggregation and difficult transportation. However, the current technical means for fiber-doped composite coatings in thermal barrier coatings have problems such as unstable quality, strict production conditions, high equipment requirements, and low production efficiency, making it difficult to be applied in industrialization. SUMMARY

[0004] In order to overcome the problems of unstable quality, strict production conditions, high equipment requirements and low production efficiency of the thermal barrier coating in the prior art, the present application aims to provide a preparation method of a fiber-toughened vertical crack composite structure coating, which can realize the preparation of a high-fracture-toughness, high-service-life, low-thermal-conductivity thermal barrier coating, and has the characteristics of low cost, high efficiency, simple process and easy large-scale use, and is expected to be applied to the surface of the hot end parts of an aero-engine and a gas turbine.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of a fiber-toughened vertical crack composite structure coating, comprising the following steps:

[0007] Mixing high-aspect-ratio ZrO2 fibers with spherical ceramic nano-powder to obtain a mixed product,

[0008] Adding the mixed product to a solvent, and then adding a dispersant to prepare a suspension;

[0009] The suspension is ultrasonically dispersed, then subjected to ball milling, and then atomized by a pressure type two-fluid air centrifugal atomizer, the atomized suspension is melted and accelerated to impact the surface of a metal substrate under the action of a wide speed range high-energy plasma spraying heat source, and a fiber toughened vertical crack composite structure coating is obtained.

[0010] Further, the proportion of ZrO2 fibers in the mixed product is 10-100wt.%.

[0011] Further, the length of the ZrO2 fibers is 100-1500 microns, and the average aspect ratio is 50.

[0012] Further, the spherical ceramic nano-powder is yttria partially stabilized zirconia, scandium oxide and yttria co-stabilized zirconia, gadolinium oxide and yttria co-stabilized zirconia, or lanthanum zirconate ceramic material.

[0013] Further, the particle size of the spherical ceramic nano-powder is 10-90nm.

[0014] Further, the content of the mixed product in the suspension is 20-30wt.%, and the content of the dispersant is 5-20wt.%.

[0015] Further, the solvent is anhydrous ethanol and / or deionized water, and the dispersant is polyethylene glycol.

[0016] Further, the rotation speed of the ball mill is 200-400r / min, and the ball milling time is 2-24h.

[0017] Further, the gas pressure of the nozzle of the pressure type two-fluid air centrifugal atomizer is 0.3-0.5MPa, the liquid pressure is 0.1-0.3MPa, and the pore size is 1.1-1.5mm.

[0018] Further, the wide speed range high-energy plasma spraying process parameters are as follows: the spraying power is 52-55kW, the spraying distance is 50-60mm, the distance between the liquid material injection position and the nozzle is 10-20mm, and the feeding rate is 10-15mL·min -1 .

[0019] The metal substrate is one of nickel-based superalloys GH4169, GH3625, GH3044 and GH3030, or one of single crystal superalloys DD3, DD5, DD6 and CMSX-6.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] In the present application, the atomized suspension is melted and accelerated to impact the surface of the metal substrate under the action of a wide-speed-range high-energy plasma spraying heat source, and a thermal barrier coating with fiber toughening and vertical crack structure is effectively prepared by using a wide-speed-range high-energy plasma jet and adopting an external liquid phase delivery method. In the present application, the suspension is sprayed out through a pressure type two-fluid air centrifugal atomizer, the atomized suspension is melted and impacts the substrate surface under the action of a wide-speed-range high-energy plasma heat source, and the liquid phase delivery particles have the advantage of avoiding the granulation link. The coating produces cracks in the process of water-cooled thermal shock cycling, and the crack propagation to the fiber will be deflected or terminated to increase the energy required for crack propagation. In addition, there are also fiber connection and pull-out in the crack. Therefore, the addition of fibers can improve the mechanical properties and service life of the coating. Compared with SiC fibers with high thermal conductivity, ZrO2 fibers have high melting point, low thermal conductivity, similar thermal expansion coefficient to YSZ, and excellent properties such as acid and alkali resistance and corrosion resistance, so ZrO2 fibers are used in the present application. The present application provides a theoretical basis for the structure design of low-thermal-conductivity and high-reliability thermal barrier coating, and has the advantages of short preparation period, simple process, easy control, large-scale production, wide application market, and technical support for the surface protection of national major equipment such as aircraft engines.

[0022] Further, the present application breaks through the key technology for preparing a fiber toughening vertical crack structure thermal barrier coating, and provides a new idea for the efficiency and service life of the thermal barrier coating. The proportion of ZrO2 fibers in the mixed product is 10-100wt.%, and when the proportion of ZrO2 fibers in the solid phase content increases, the porosity of the thermal barrier coating decreases and the vertical crack density increases. Compared with when no ZrO2 fibers are added, the fracture toughness and bonding strength of the thermal barrier coating are expected to be greatly improved, which ultimately leads to the improvement of the water-cooled thermal shock performance of the thermal barrier coating. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0024] Figure 1 Fig. 1 is a schematic diagram of the micro-morphology of the raw materials of Example 1 of the present application, wherein (a) is ZrO2 fiber and (b) is YSZ nano-powder.

[0025] Figure 2 Fig. 2 is a SEM image of the coating obtained in Example 1 of the present application, wherein (a) is a cross-sectional view, (b) is a surface view, and (c) is a local enlarged view of Fig. (b).

[0026] Figure 3 Fig. 3 is a molten droplet spreading morphology diagram obtained in Example 1 of the present application, wherein (a) is an enlarged view of 1000, and (b) is an enlarged view of 5000.

[0027] Figure 4The macro-morphology diagram of the coating obtained from the present application embodiment 1 after water cooling thermal shock cycle.

[0028] Figure 5 The SEM image of the coating obtained from the present application embodiment 2; wherein, (a) is a cross-section diagram; (b) is a surface diagram.

[0029] Figure 6 The cross-section micro-morphology diagram of the coating obtained from the present application embodiment 3 under different solvent types; wherein, (a) is that the solvent is deionized water; (b) is that the solvent is anhydrous ethanol. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0031] There are many ways to prepare fibers, including chemical vapor deposition, hydrothermal method, template method, electrospinning method, high temperature and high pressure method, molten salt method, etc., wherein under the premise of good control of holding time and other conditions, the molten salt method can obtain fibers with good quality and high aspect ratio.

[0032] The preparation method of the fiber toughened vertical crack composite structure coating of the present application adopts a liquid phase spraying process, including the following steps:

[0033] I. The high aspect ratio ZrO2 fiber is mechanically mixed with spherical ceramic nano powder to obtain a mixed product, the proportion of ZrO2 fiber in the mixed product is 10-100wt.%, the length of the ZrO2 fiber is 100-1500μm, and the average aspect ratio is 50; the spherical ceramic nano powder is YSZ (yttria partially stabilized zirconia), ScYSZ (scandium and yttria co-stabilized zirconia), GdYSZ (gadolinium and yttria co-stabilized zirconia) or LZ (lanthanum zirconate) ceramic material. The particle size of the spherical ceramic nano powder is 10-90nm.

[0034] II. The mixed product in step I is added to a solvent, and a dispersant is added to form a suspension. The solid phase (i.e. the mixed product) content in the suspension is about 20-30wt.%, and the dispersant content is about 5-20wt.%.

[0035] The solvent is anhydrous ethanol and / or deionized water, and the dispersant is polyethylene glycol (PEG-600).

[0036] III. The suspension in step II is ultrasonically dispersed for 1h, and then ball milled, the ball mill speed is 200-400r / min, and the ball milling time is 2-24h.

[0037] Four, the mixed solution treated in step three is placed on a magnetic stirrer for stirring, and the mixed solution is transmitted to a pressure type two-fluid air centrifugal atomizer by a peristaltic pump (only pressure can be adjusted), the rotation speed of the peristaltic pump is 1-300 mL / min, the atomized suspension is melted and accelerated to impact the surface of the metal substrate under the action of a wide speed range high-energy plasma spraying heat source, so that a fiber toughened vertical crack composite structure coating is obtained. Among them, the method of using a direct current driven plasma arc as a heat source to heat ceramic, alloy, metal and other materials to a molten or semi-molten state, and then sprayed at high speed to the surface of the pretreated workpiece to form a firmly adhered surface layer, the temperature and speed of the ceramic flying particles can be changed by adjusting the voltage, current, argon and hydrogen flow rate in the spraying parameters.

[0038] Among them, the gas pressure of the nozzle of the pressure type two-fluid air centrifugal atomizer is 0.3-0.5 MPa, the liquid pressure is 0.1-0.3 MPa, and the pore size is 1.1-1.5 mm.

[0039] The wide speed range high-energy plasma spraying process parameters used in step four are as follows: the spraying power is 52-55 kW, the spraying distance is 50-60 mm, the distance between the liquid material injection position and the nozzle is 10-20 mm, and the feeding rate is 10-15 mL·min -1 .

[0040] The metal substrate is one of nickel-based superalloys GH4169, GH3625, GH3044 and GH3030 or one of single crystal superalloys DD3, DD5, DD6 and CMSX-6.

[0041] Since the wettability of the interface between the fiber and the ceramic matrix is the key to affecting the toughening effect, the difference between the physical properties of the two will have a negative impact on the toughening effect of the coating. In addition, the fiber must also have high melting point, high strength and low thermal conductivity and other characteristics. High melting point determines whether the fiber can be melted in the plasma jet and finally remain in the coating structure, high strength determines the amount of load that the coating can withstand during service, and low thermal conductivity determines the overall thermal insulation performance of the coating. Compared with SiC fibers with high thermal conductivity, ZrO2 fibers have high melting point, low thermal conductivity, similar thermal expansion coefficient to YSZ, and excellent performance such as acid and alkali resistance and corrosion resistance, so ZrO2 fibers are used in the present application.

[0042] The following is a specific embodiment.

[0043] Example 1

[0044] A method for preparing a fiber toughened vertical crack composite structure coating according to the present embodiment includes the following steps:

[0045] 1) ZrO2 fibers with an aspect ratio of approximately 50 were mechanically mixed with spherical ceramic nanoparticles to obtain a mixed product. The proportion of ZrO2 fibers in the mixed product was 100 wt.%. The spherical ceramic nanoparticles were YSZ (yttrium-stabilized zirconia). The particle size of the spherical ceramic nanoparticles was 10-90 nm.

[0046] The solid product was added to a solvent, and then a dispersant was added to prepare a suspension. The solid content in the suspension was 20 wt.%; the dispersant was polyethylene glycol (PEG-600), and the dispersant content in the suspension was 5 wt.%; the solvent was anhydrous ethanol.

[0047] 2) The suspension prepared in step 1) is ultrasonically dispersed for 1 hour, and then ball milled at a speed of 300 r / min for 12 hours.

[0048] 3) The suspension processed in step 2) is placed on a magnetic stirrer and stirred. It is then pumped via a peristaltic pump (pressure adjustable only) to the centrifugal atomizing nozzle above the plasma spray gun of a pressure-type two-fluid air centrifugal atomizer. The peristaltic pump speed is 300 mL / min. The spraying process parameters are adjusted. The atomized suspension melts under the action of the plasma heat source and accelerates its impact on the metal substrate surface, thus obtaining a fiber-reinforced vertical crack composite structure coating. The spraying process parameters are as follows: spraying power 52 kW, spraying distance 60 mm, injection position (distance between the liquid injection position and the nozzle) 20 mm, and feed rate 12 mL / min. -1 .

[0049] The nozzle of the pressure-type two-fluid air centrifugal atomizer has a gas pressure of 0.4 MPa, a liquid pressure of 0.2 MPa, and an orifice diameter of 1.3 mm.

[0050] 4) The morphology of the prepared fiber-toughened vertical crack composite structure coating was analyzed.

[0051] 5) Place the coating in a muffle furnace at 1100℃ and hold for 5 minutes. Then quickly quench the coating and check the number of cycles of the coating based on 10% failure area. The service life of the coating is evaluated by the number of cycles.

[0052] See Figure 1 As can be seen from (a) and (b), the fibers are long and thin and resemble whiskers, while the powder is small and resembles flocculent clumps.

[0053] See Figure 2In the middle of (a), (b) and (c), it can be seen that the pores and unmelted particles inside the coating are less, indicating that the bonding force between the coating and the substrate is better; there are more vertical cracks, which can effectively release the residual stress inside the coating, indicating that the interface stability of the coating is good, the thermal shock resistance is excellent, and the service life is longer.

[0054] Referring to Figure 3 In the middle of (a) and (b), from Figure 3 It can be seen from the middle of (a) that the flat particle spreading morphology of the solid phase composition is mainly elliptical, and there is almost no splashing phenomenon in the edge area; from Figure 3 It can be seen from the middle of (b) that the surface of the flat particle of the droplet is relatively smooth and almost no crack exists. In addition, ZrO2 fibers are found in a single flat particle and near the particle, indicating that the ZrO2 fibers are not completely melted.

[0055] Referring to Figure 4 It can be seen that when the proportion of ZrO2 fibers in the solid phase content is 100wt.%, the water-cooled thermal shock cycle number of the thermal barrier coating is 190 times. After 135 cycles, point peeling occurs in the center area of the sample. When the cycle number increases to 140 times, sheet peeling occurs in the edge area of the sample, and the peeling area is 0.84%. When the cycle number further increases, the peeling area increases to 6.68%. It can be seen that the peeling speed of the thermal barrier coating is slow at the initial stage of the cycle. When the coating begins to point peeling under the action of water-cooled thermal shock, with the increase of the cycle number, the coating rapidly presents large sheet peeling.

[0056] Example 2

[0057] The difference between this embodiment and example 1 is that: the solid phase product in step 1) is obtained by mechanically mixing fibers and powders in a certain mass ratio. Among them, the proportion of ZrO2 fibers in the mixed product is 50wt.%; the others are the same as example 1.

[0058] Referring to Figure 5 It can be seen from the middle of (a) and (b) that there are non-penetrating vertical cracks in the coating structure, and there are also horizontal crack branches near the vertical cracks; the coating has "mountain peak" protrusions, which are caused by the "reinforced concrete structure" formed by the addition of fibers in the coating, which hinders the migration and peeling of the molten particles.

[0059] Example 3

[0060] The difference between this embodiment and example 1 is that: the type of solvent used in step 1) is deionized water. The others are the same as example 1.

[0061] Referring to Figure 6 In the middle of (a) and (b), fromFigure 6 From Fig. (a), it can be seen that the coating prepared with deionized water as solvent has a loose porous structure, and there are a large number of pores and unmelted particles in the coating. Figure 6 From Fig. (b), it can be seen that compared with the coating prepared with water as solvent, the coating prepared with anhydrous ethanol as solvent has improved compactness, and vertical cracks appear in the coating.

[0062] Example 4

[0063] 1) ZrO2 fibers with a high aspect ratio of about 50 were mechanically mixed with spherical ceramic nano-powder to obtain a mixed product, and the proportion of ZrO2 fibers in the mixed product was 10 wt.%. The spherical ceramic nano-powder was YSZ (yttria-stabilized zirconia). The particle size of the spherical ceramic nano-powder was 10-90 nm.

[0064] The solid-phase product was added to a solvent, and a dispersant was added to prepare a suspension. In the suspension, the solid-phase content was 30 wt.%, the dispersant was polyethylene glycol (PEG-600), and the dispersant content in the suspension was 20 wt.%. The solvent was a mixture of anhydrous ethanol and water in a volume ratio of 1:1.

[0065] 2) The suspension prepared in step 1) was ultrasonically dispersed for 1 h, and then ball-milled at a speed of 200 r / min for 24 h.

[0066] 3) The suspension treated in step 2) was placed on a magnetic stirrer for stirring, and was transferred to a centrifugal atomization nozzle above a plasma torch of a pressure-type two-fluid air centrifugal atomizer through a peristaltic pump (only capable of adjusting pressure) at a speed of 1 mL / min. The spraying process parameters were adjusted, and the atomized suspension was melted and accelerated to impact the surface of a nickel-based superalloy GH4169 substrate under the action of a plasma heat source, thereby obtaining a fiber-toughened vertical crack composite structure coating. The spraying process parameters were as follows: spraying power was 52 kW, spraying distance was 55 mm, injection position (distance between liquid injection position and nozzle) was 10 mm, and feeding rate was 15 mL·min -1 .

[0067] The gas pressure of the nozzle of the pressure-type two-fluid air centrifugal atomizer was 0.3 MPa, the liquid pressure was 0.1 MPa, and the pore size was 1.1 mm.

[0068] Example 5

[0069] 1) ZrO2 fibers with a high aspect ratio of about 50 were mechanically mixed with spherical ceramic nano-powder to obtain a mixed product, the proportion of ZrO2 fibers in the mixed product was 100 wt.%; the spherical ceramic nano-powder was ScYSZ (zirconia stabilized by scandium and yttrium oxide). The particle size of the spherical ceramic nano-powder was 10-90 nm.

[0070] The solid phase product was added to the solvent, and a dispersing agent was added to prepare a suspension. Among them, the solid phase content in the suspension was 25 wt.%; the dispersing agent was polyethylene glycol (PEG-600), and the dispersing agent content in the suspension was 5 wt.%; the solvent was deionized water.

[0071] 2) The suspension prepared in step 1) was ultrasonically dispersed for 1 h, and then ball milled at a speed of 400 r / min for 2 h.

[0072] 3) The suspension treated in step 2) was placed on a magnetic stirrer for stirring, and was transferred to the centrifugal atomization nozzle above the plasma torch of the pressure two-fluid air centrifugal atomizer through a peristaltic pump (only pressure can be adjusted) at a speed of 20 mL / min. The spraying process parameters were adjusted, and the atomized suspension was melted and accelerated to impact the surface of the nickel-based superalloy GH3625 substrate under the action of the plasma heat source, thereby obtaining a fiber toughening vertical crack composite structure coating. The spraying process parameters are as follows: the spraying power is 55 kW, the spraying distance is 58 mm, the injection position (the distance between the liquid material injection position and the nozzle) is 20 mm, and the feeding rate is 10 mL·min -1 .

[0073] Among them, the gas pressure of the nozzle of the pressure two-fluid air centrifugal atomizer is 0.5 MPa, the liquid pressure is 0.2 MPa, and the pore size is 1.5 mm.

[0074] Example 6

[0075] 1) ZrO2 fibers with a high aspect ratio of about 50 were mechanically mixed with spherical ceramic nano-powder to obtain a mixed product, the proportion of ZrO2 fibers in the mixed product was 30 wt.%; the spherical ceramic nano-powder was GdYSZ (zirconia stabilized by gadolinium and yttrium oxide). The particle size of the spherical ceramic nano-powder was 10-90 nm.

[0076] The solid phase product was added to the solvent, and a dispersing agent was added to prepare a suspension. Among them, the solid phase content in the suspension was 22 wt.%; the dispersing agent was polyethylene glycol (PEG-600), and the dispersing agent content in the suspension was 15 wt.%; the solvent was a mixture of anhydrous ethanol and water with a volume ratio of 1:2.

[0077] 2) The prepared suspension in step 1) is ultrasonically dispersed for 1 h, and then subjected to ball milling at a speed of 300 r / min for 8 h.

[0078] 3) The suspension treated in step 2) is placed on a magnetic stirrer for stirring, and is transferred to a centrifugal atomization nozzle above a plasma torch of a pressure type two-fluid air centrifugal atomizer by a peristaltic pump (only capable of adjusting pressure) at a speed of 80 mL / min. The spraying process parameters are adjusted, and the atomized suspension is melted and accelerated to impact the single crystal superalloy DD3 substrate surface under the action of the plasma heat source, so as to obtain a fiber toughening vertical crack composite structure coating. The spraying process parameters are as follows: spraying power is 55 kW, spraying distance is 52 mm, injection position (distance between liquid injection position and nozzle) is 15 mm, and feeding rate is 11 mL·min -1 .

[0079] The gas pressure of the nozzle of the pressure type two-fluid air centrifugal atomizer is 0.4 MPa, the liquid pressure is 0.3 MPa, and the pore size is 1.2 mm.

[0080] Example 7

[0081] 1) ZrO2 fibers with a high aspect ratio of about 50 are mechanically mixed with spherical ceramic nano-powder to obtain a mixed product, and the proportion of ZrO2 fibers in the mixed product is 60 wt.%. The spherical ceramic nano-powder is LZ (lanthanum zirconate) ceramic material. The particle size of the spherical ceramic nano-powder is 10-90 nm.

[0082] The solid phase product is added to a solvent, and a dispersant is further added to prepare a suspension. The solid phase content in the suspension is 28 wt.%. The dispersant is polyethylene glycol (PEG-600), and the dispersant content in the suspension is 10 wt.%. The solvent is a mixture of anhydrous ethanol and water with a volume ratio of 2:1.

[0083] 2) The prepared suspension in step 1) is ultrasonically dispersed for 1 h, and then subjected to ball milling at a speed of 250 r / min for 15 h.

[0084] 3) The suspension treated in step 2) is placed on a magnetic stirrer for stirring, and is transmitted to the centrifugal atomization nozzle above the plasma torch of the pressure two-fluid air centrifugal atomizer through a peristaltic pump (only pressure can be adjusted), the rotation speed of the peristaltic pump is 300 mL / min, the spraying process parameters are adjusted, and the atomized suspension is melted and accelerated to impact the single crystal superalloy CMSX-6 substrate surface under the action of the plasma heat source, so that a fiber toughened vertical crack composite structure coating is obtained. The spraying process parameters are as follows: the spraying power is 53 kW, the spraying distance is 55 mm, the injection position (the distance between the liquid material injection position and the nozzle) is 13 mm, and the feeding rate is 13 mL·min -1 .

[0085] The gas pressure of the nozzle of the pressure two-fluid air centrifugal atomizer is 0.3 MPa, the liquid pressure is 0.3 MPa, and the pore size is 1.3 mm.

[0086] Example 8

[0087] 1) ZrO2 fibers with a high aspect ratio of about 50 are mechanically mixed with spherical ceramic nano-powder to obtain a mixed product, the proportion of ZrO2 fibers in the mixed product is 70 wt.%; the spherical ceramic nano-powder is YSZ (yttria-stabilized zirconia). The particle size of the spherical ceramic nano-powder is 10-90 nm.

[0088] The solid phase product is added to a solvent, and a dispersant is added to form a suspension. The solid content in the suspension is 25 wt.%; the dispersant is polyethylene glycol (PEG-600), and the dispersant content in the suspension is 8 wt.%; the solvent is anhydrous ethanol.

[0089] 2) The suspension prepared in step 1) is ultrasonically dispersed for 1 h, and then ball milled at a rotation speed of 300 r / min for 20 h.

[0090] 3) The suspension treated in step 2) is placed on a magnetic stirrer for stirring, and is transmitted to the centrifugal atomization nozzle above the plasma torch of the pressure two-fluid air centrifugal atomizer through a peristaltic pump (only pressure can be adjusted), the rotation speed of the peristaltic pump is 200 mL / min, the spraying process parameters are adjusted, and the atomized suspension is melted and accelerated to impact the single crystal superalloy CMSX-6 substrate surface under the action of the plasma heat source, so that a fiber toughened vertical crack composite structure coating is obtained. The spraying process parameters are as follows: the spraying power is 53 kW, the spraying distance is 55 mm, the injection position (the distance between the liquid material injection position and the nozzle) is 13 mm, and the feeding rate is 13 mL·min -1 .

[0091] The gas pressure of the nozzle of the pressure type two-fluid air centrifugal atomizer is 0.5 MPa, the liquid pressure is 0.2 MPa, and the pore size is 1.4 mm.

[0092] Example 9

[0093] 1) ZrO2 fibers with a high aspect ratio of about 50 were mechanically mixed with spherical ceramic nano-powder to obtain a mixed product, and the proportion of ZrO2 fibers in the mixed product was 85 wt.%; the spherical ceramic nano-powder was LZ (lanthanum zirconate) ceramic material. The particle size of the spherical ceramic nano-powder was 10-90 nm.

[0094] The solid phase product was added to a solvent, and a dispersant was added to form a suspension. In the suspension, the solid phase content was 24 wt.%; the dispersant was polyethylene glycol (PEG-600), and the dispersant content in the suspension was 17 wt.%; and the solvent was anhydrous ethanol.

[0095] 2) The suspension prepared in step 1) was ultrasonically dispersed for 1 h, and then ball milling treatment was performed at a ball mill speed of 350 r / min for 5 h.

[0096] 3) The suspension treated in step 2) was placed on a magnetic stirrer for stirring, and was conveyed to the centrifugal atomizing nozzle above the plasma torch of the pressure type two-fluid air centrifugal atomizer through a peristaltic pump (only pressure can be adjusted) at a speed of 150 mL / min. The spraying process parameters were adjusted, and the atomized suspension was melted and accelerated to impact the surface of the nickel-based superalloy GH3030 substrate under the action of the plasma heat source, thereby obtaining a fiber-reinforced vertical crack composite structure coating. The spraying process parameters are as follows: the spraying power is 52 kW, the spraying distance is 60 mm, the injection position (the distance between the liquid material injection position and the nozzle) is 17 mm, and the feeding rate is 15 mL·min -1 .

[0097] The gas pressure of the nozzle of the pressure type two-fluid air centrifugal atomizer is 0.4 MPa, the liquid pressure is 0.1 MPa, and the pore size is 1.1 mm.

[0098] The above only describes the best embodiments of the present application, but cannot be understood as limiting the claims. The present application is not limited to the above embodiments, and the specific structure allows changes. Any changes made within the protection scope of the independent claims of the present application are within the protection scope of the present application.

[0099] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for preparing a fiber-reinforced vertical crack composite structure coating, characterized in that, Includes the following steps: High aspect ratio ZrO2 fibers were mixed with spherical ceramic nanoparticles to obtain a mixed product. The mixture is added to a solvent, and then a dispersant is added to form a suspension; The suspension is ultrasonically dispersed, then ball-milled, and then atomized by a pressure-type two-fluid air centrifugal atomizer. The atomized suspension melts and accelerates to impact the surface of the metal substrate under the action of a wide-velocity high-energy plasma spraying heat source, thus obtaining a fiber-toughened vertical crack composite structure coating. The spherical ceramic nanopowders are yttrium-stabilized zirconium oxide, scandium oxide and yttrium oxide co-stabilized zirconium oxide, gadolinium oxide and yttrium oxide co-stabilized zirconium oxide, or lanthanum zirconate ceramic materials; The nozzle of the pressure-type two-fluid air centrifugal atomizer has a gas pressure of 0.3-0.5 MPa, a liquid pressure of 0.1-0.3 MPa, and an orifice diameter of 1.1-1.5 mm. The parameters for wide-velocity high-energy plasma spraying are as follows: spraying power 52-55 kW, spraying distance 50-60 mm, distance between liquid injection position and nozzle 10-20 mm, and feed rate 10-15 mL·min. -1 ; The metal matrix is ​​one of the nickel-based superalloys GH4169, GH3625, GH3044 and GH3030 or one of the single-crystal superalloys DD3, DD5, DD6 and CMSX-6.

2. The method for preparing the fiber-reinforced vertical crack composite structure coating according to claim 1, characterized in that, The proportion of ZrO2 fibers in the mixed product is 10-100 wt.%.

3. The method for preparing the fiber-reinforced vertical crack composite structure coating according to claim 1, characterized in that, The ZrO2 fibers range in length from 100 to 1500 μm and have an average aspect ratio of 50.

4. The method for preparing the fiber-reinforced vertical crack composite structure coating according to claim 1, characterized in that, The particle size of the spherical ceramic nanopowder is 10-90 nm.

5. The method for preparing the fiber-reinforced vertical crack composite structure coating according to claim 1, characterized in that, The content of mixed products in the suspension is 20-30 wt.%, and the content of dispersant is 5-20 wt.%.

6. The method for preparing the fiber-reinforced vertical crack composite structure coating according to claim 1, characterized in that, The solvent is anhydrous ethanol and / or deionized water, and the dispersant is polyethylene glycol.

7. The method for preparing the fiber-reinforced vertical crack composite structure coating according to claim 1, characterized in that, The ball mill speed is 200-400 r / min, and the ball milling time is 2-24 h.

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