High-temperature resistant, long-life carbide multilayer special functional coatings and their preparation methods

Abstract

This invention discloses a high-temperature resistant, long-life carbide-based multilayer special functional coating and its preparation method. The method includes the following steps: (1) carbide coating; (2) powder preparation; (3) transition layer spraying; (4) special functional layer spraying; and (5) protective layer spraying. The carbide-based multilayer special functional coating prepared by this invention can greatly improve the coating's high-temperature resistance, oxidation resistance, and service life, and can meet the needs of various fields for special functional coatings.

Description

Technical Field

[0001] This invention belongs to the field of special functional coating technology, and relates to high-temperature resistant, long-life carbide multilayer special functional coatings and their preparation methods. Background Technology

[0002] Aero engines are a crucial application area for special functional coatings. These coatings endow key components with different functionalities, enabling them to meet the requirements of various operating conditions and have become one of the core technologies of new aero engines. Currently, carbide functional coatings are not yet maturely applied due to various reasons. Therefore, there is an urgent need to optimize the temperature resistance, oxidation resistance, and other properties of carbide functional coatings to meet the actual usage requirements of different components in advanced aero engines.

[0003] Currently, the most researched carbide coatings use materials such as SiC, TiC, CaC2, and ZrC. These materials exhibit poor oxidation resistance at high temperatures and are prone to oxidation and decomposition during prolonged use at high temperatures, leading to coating failure and peeling, which fails to meet application requirements. Therefore, there is an urgent need to develop a high-temperature resistant, long-life, multi-layered carbide-based special functional coating to ensure the special functional requirements of different components in aero-engines. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature resistant, long-life carbide multilayer special functional coating and its preparation method, which can greatly improve the coating's high-temperature resistance, oxidation resistance and service life, and can meet the needs of various fields for special functional coatings.

[0005] The objective of this invention is achieved through the following technical solution: a high-temperature resistant, long-life carbide multilayer special functional coating, wherein the multilayer special functional coating comprises, in sequence, a metal bonding layer, an intermediate layer, a special functional layer, a silicon layer, a mullite layer, and a ytterbium silicate layer; the special functional layer comprises coated carbide powder, Al2O3, thermal barrier system material, and fumed SiO2, wherein the mass ratio of coated carbide powder is 63-77%, the mass ratio of Al2O3 is 10-16%, the mass ratio of thermal barrier system material is 10-16%, and the mass ratio of fumed SiO2 is 3-5%.

[0006] The multilayer special functional coating consists of a metal bonding layer, an intermediate layer, a special functional layer, a silicon layer, a mullite layer, and a ytterbium silicate layer, with the following thicknesses: metal bonding layer 0.1mm-0.12mm, intermediate layer 0.1mm-0.12mm, special functional layer 1-1.1mm, silicon layer 50μm-80μm, mullite layer 60μm-90μm, and ytterbium silicate layer 70μm-80μm.

[0007] The thermal barrier system material is one or more of YSZ, La2Zr2O7, and Gd2Zr2O7.

[0008] The method for preparing the special functional layer spray powder includes the following steps:

[0009] (1) Carbide coating: A layer of boride is coated on the surface of the carbide using mechanical alloying technology;

[0010] (2) Preparation of spray powder:

[0011] 1) Slurry preparation: The coated carbide powder, Al2O3, thermal barrier system material, gaseous SiO2, polyvinyl alcohol and deionized water are weighed according to the specified ratio and put into a ball mill jar for ball milling.

[0012] 2) Spherical powder is prepared by spray granulation machine: spray granulation machine inlet temperature 300-320℃, outlet temperature 100-120℃, spray disc speed 35-45Hz, and feed speed 30-40rpm;

[0013] 3) Granulated powder sintering: The equipment used for granulated powder sintering is an atmosphere sintering furnace. The sintering process is as follows: hold at 500-600℃ for 2-3 hours, continue to heat up to 1000-1200℃ and hold for 2-3 hours, with a heating rate of 5-10℃ / min, and cool down with the furnace. Ar protective atmosphere.

[0014] In step (1), the carbide is one of SiC, TiC, or Ti3SiC2; the boride is one of HfB2, TaB2, or ZrB2.

[0015] The specific method for carbide coating in step (1) is as follows: placing the carbide and boride on a planetary ball mill for ball milling, with a ball-to-material ratio of 8-10:1, a rotation speed of 200-300 r / min, and a time of 5-10 h. The ratio of carbide to boride is 0.8-0.9:0.1-0.2.

[0016] In step (2), the mass of deionized water is 1-2 times the total mass of the powder, and the mass of polyvinyl alcohol is 1-2% of the total mass of the powder.

[0017] The ball milling in step (2) is carried out using a horizontal ball mill with a ball-to-material ratio of 2-4:1, a mill speed of 35-45 r / min, and a milling time of 12-15 h.

[0018] The method for preparing the high-temperature resistant, long-life carbide-based multilayer special functional coating includes the following steps:

[0019] (1) Apply a metal bonding layer to the high-temperature alloy substrate after sandblasting; the spraying process is supersonic flame spraying, and the spraying parameters are: oxygen flow rate 1850-1950SCFH, kerosene flow rate 20-25L / h, carrier gas flow rate 10-15SCFH, powder feeding rate 4-8r / min, and spraying distance 350-400mm.

[0020] (2) Spray an intermediate layer onto the metal adhesive layer. The intermediate layer material is a mixture of adhesive layer material and special functional layer material. The adhesive layer material accounts for 40%-60% of the mass, and the rest is special functional layer material. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 540-560A, main gas Ar flow rate 45-50NLPM, auxiliary gas H2 flow rate 6-10NLPM, carrier gas Ar flow rate 2-4NLPM, powder feeding rate 18-22g / min, and spraying distance 120-140mm.

[0021] (3) Using atmospheric plasma spraying technology, the special functional layer is sprayed onto the intermediate layer with spray powder. Spraying process parameters: current 590-620A, main gas Ar flow rate 38-45NLPM, auxiliary gas H2 flow rate 13-15NLPM, carrier gas Ar flow rate 3-4NLPM, powder feeding rate 10-20g / min, spraying distance 100-110mm.

[0022] (4) A silicon layer is sprayed on the special functional layer. The silicon layer material is Si powder with a particle size of 20-70μm. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 580-620A, main gas Ar flow rate 43-47NLPM, auxiliary gas H2 flow rate 7-10NLPM, carrier gas Ar flow rate 3.5-4.5NLPM, powder feeding rate 10-20g / min, and spraying distance 90-110mm.

[0023] (5) Spray a mullite layer on the silicon layer. The mullite layer material is 3Al2O32SiO2 powder with a particle size of 10-50μm. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 610-630A, main gas Ar flow rate 45-50NLPM, auxiliary gas H2 flow rate 7-9NLPM, carrier gas Ar flow rate 3-5NLPM, powder feeding rate 10-15g / min, and spraying distance 95-105mm.

[0024] (6) A ytterbium silicate layer is sprayed onto the mullite layer. The ytterbium silicate layer material is Yb₂Si₂O₇ powder with a particle size of 10-80 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 600-620 A, main gas Ar flow rate 43-48 NLPM, auxiliary gas H₂ flow rate 6-8 NLPM, carrier gas Ar flow rate 4-5 NLPM, powder feed rate 15-20 g / min, and spraying distance 100-105 mm. The metal bonding layer material is one of NiCrAlY, CoCrAlY, and NiCoCrAlY.

[0025] Advantages and beneficial effects of the present invention:

[0026] (1) Carbide materials have poor high-temperature oxidation resistance, resulting in poor performance of carbide coatings during high-temperature testing due to oxidation. The thermal shock resistance at 900℃ is only 300 cycles, and the long-term temperature resistance at 900℃ is only 100 hours. This invention innovatively coats the surface of carbide with a layer of ultra-high temperature boride ceramic. This type of boride readily reacts with oxygen at high temperatures to form dense B2O3. B2O3 covers and fills the voids in the carbide, inhibiting oxygen migration and diffusion, isolating the carbide from oxygen, and improving the high-temperature oxidation resistance of the carbide material. The prepared carbide coating has good oxidation resistance during high-temperature testing, achieving 500 thermal shock cycles at 900℃ and 300 hours of long-term temperature resistance at 900℃.

[0027] (2) Carbide-based special functional coatings are prone to failure and peeling when used for a long time in high-temperature environments, mainly due to the oxidative decomposition of carbides. During high-temperature testing, the thermal shock resistance at 900℃ can only reach 300 cycles, and the long-term temperature resistance at 900℃ can only reach 100 hours. In addition to adding Al2O3, YSZ, La2Zr2O7, and Gd2Zr2O7 ceramic materials with good temperature resistance to the carbide coating, this invention also innovatively adds gaseous SiO2. The particle size range of gaseous SiO2 is 10-40nm. It can easily form a SiO2 protective film in the coating, covering the coating surface and filling the pores of the coating, isolating the carbides in the coating from oxygen, and improving the high-temperature oxidation resistance of the carbide-based special functional coating. During high-temperature testing, the thermal shock resistance at 900℃ can reach 700 cycles, and the long-term temperature resistance at 900℃ can reach 700 hours.

[0028] (3) This invention innovatively sprays a protective layer onto the surface of the carbide coating, further isolating it from oxygen in the environment, improving the high-temperature oxidation resistance of the carbide coating, and further extending its service life under high-temperature conditions. During high-temperature testing, it can withstand 1000 thermal shock cycles at 900℃, and long-term temperature resistance at 900℃ can reach 1000 hours. After long-term temperature resistance, the oxidation weight gain per unit area of ​​the coating is as low as 3.25-3.86 g·m³. -2 . Attached Figure Description

[0029] Figure 1 The coating structure of multilayer special functional coatings;

[0030] Figure 2 Scanned surface images of the carbide-coated powder prepared in Example 1; where: a) is a morphology image; b is a Si elemental distribution image; c is a C elemental distribution image; d is a Ta elemental distribution image; e is a B elemental distribution image;

[0031] Figure 3 Scanned surface images of the carbide-coated powder prepared in Example 2; where: a) is a morphology image; b is a Ti elemental distribution map; c is a C elemental distribution map; d is a Ta elemental distribution map; e is a B elemental distribution map;

[0032] Figure 4 Scanned image of the carbide-coated powder prepared in Example 3. Wherein: a) is the morphology image; b is the elemental distribution of Ti; c is the elemental distribution of Si; d is the elemental distribution of C; e is the elemental distribution of Zr; f is the elemental distribution of B. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0034] A high-temperature resistant, long-life carbide-based multilayer special functional coating is disclosed. The multilayer special functional coating comprises, in sequence, a metal bonding layer, an intermediate layer, a special functional layer, a silicon layer, a mullite layer, and a ytterbium silicate layer. The special functional layer includes coated carbide powder, Al2O3, thermal barrier system material, and fumed SiO2, wherein the mass ratio of coated carbide powder is 63-77%, the mass ratio of Al2O3 is 10-16%, the mass ratio of thermal barrier system material is 10-16%, and the mass ratio of fumed SiO2 is 3-5%.

[0035] The multilayer special functional coating consists of a metal bonding layer, an intermediate layer, a special functional layer, a silicon layer, a mullite layer, and a ytterbium silicate layer, with the following thicknesses: metal bonding layer 0.1mm-0.12mm, intermediate layer 0.1mm-0.12mm, special functional layer 1-1.1mm, silicon layer 50μm-80μm, mullite layer 60μm-90μm, and ytterbium silicate layer 70μm-80μm.

[0036] The thermal barrier system material is one or more of YSZ, La2Zr2O7, and Gd2Zr2O7.

[0037] A method for preparing spray powder for special functional layers includes the following steps:

[0038] (1) Carbide coating: A layer of boride is coated on the surface of the carbide using mechanical alloying technology;

[0039] (2) Preparation of spray powder:

[0040] 1) Slurry preparation: The coated carbide powder, Al2O3, thermal barrier system material, gaseous SiO2, polyvinyl alcohol, and deionized water are weighed according to the specified ratio and placed into a ball mill jar for ball milling; the carbide is one of SiC, TiC, and Ti3SiC2; the boride is one of HfB2, TaB2, and ZrB2.

[0041] The specific method for carbide coating is as follows: place the carbide and boride in a planetary ball mill and ball mill them at a ball-to-material ratio of 8-10:1, a rotation speed of 200-300 r / min, and a time of 5-10 h. The ratio of carbide to boride is 0.8-0.9:0.1-0.2.

[0042] 2) Spherical powder is prepared using a spray granulator: the spray granulator inlet temperature is 300-320℃, the outlet temperature is 100-120℃, the spray disc speed is 35-45Hz, and the feed speed is 30-40rpm; the mass of deionized water is 1-2 times the total mass of the powder, and the mass of polyvinyl alcohol is 1-2% of the total mass of the powder. The ball milling is carried out using a horizontal ball mill, with a ball-to-powder ratio of 2-4:1, a mill barrel speed of 35-45r / min, and a ball milling time of 12-15h.

[0043] 3) Granulated powder sintering: The equipment used for granulated powder sintering is an atmosphere sintering furnace. The sintering process is as follows: hold at 500-600℃ for 2-3 hours, continue to heat up to 1000-1200℃ and hold for 2-3 hours, with a heating rate of 5-10℃ / min, and cool down with the furnace. Ar protective atmosphere.

[0044] The mass of deionized water is 1-2 times the total mass of the powder, and the mass of polyvinyl alcohol is 1-2% of the total mass of the powder.

[0045] The method for preparing the high-temperature resistant, long-life carbide-based multilayer special functional coating includes the following steps:

[0046] (1) Apply a metal bonding layer to the high-temperature alloy substrate after sandblasting; the spraying process is supersonic flame spraying, and the spraying parameters are: oxygen flow rate 1850-1950SCFH, kerosene flow rate 20-25L / h, carrier gas flow rate 10-15SCFH, powder feeding rate 4-8r / min, and spraying distance 350-400mm.

[0047] (2) Spray an intermediate layer onto the metal adhesive layer. The intermediate layer material is a mixture of adhesive layer material and special functional layer material. The adhesive layer material accounts for 40%-60% of the mass, and the rest is special functional layer material. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 540-560A, main gas Ar flow rate 45-50NLPM, auxiliary gas H2 flow rate 6-10NLPM, carrier gas Ar flow rate 2-4NLPM, powder feeding rate 18-22g / min, and spraying distance 120-140mm.

[0048] (3) Using atmospheric plasma spraying technology, the special functional layer is sprayed onto the intermediate layer with spray powder. Spraying process parameters: current 590-620A, main gas Ar flow rate 38-45NLPM, auxiliary gas H2 flow rate 13-15NLPM, carrier gas Ar flow rate 3-4NLPM, powder feeding rate 10-20g / min, spraying distance 100-110mm.

[0049] (4) A silicon layer is sprayed on the special functional layer. The silicon layer material is Si powder with a particle size of 20-70μm. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 580-620A, main gas Ar flow rate 43-47NLPM, auxiliary gas H2 flow rate 7-10NLPM, carrier gas Ar flow rate 3.5-4.5NLPM, powder feeding rate 10-20g / min, and spraying distance 90-110mm.

[0050] (5) Spray a mullite layer on the silicon layer. The mullite layer material is 3Al2O32SiO2 powder with a particle size of 10-50μm. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 610-630A, main gas Ar flow rate 45-50NLPM, auxiliary gas H2 flow rate 7-9NLPM, carrier gas Ar flow rate 3-5NLPM, powder feeding rate 10-15g / min, and spraying distance 95-105mm.

[0051] (6) A ytterbium silicate layer is sprayed onto the mullite layer. The ytterbium silicate layer material is Yb₂Si₂O₇ powder with a particle size of 10-80 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 600-620 A, main gas Ar flow rate 43-48 NLPM, auxiliary gas H₂ flow rate 6-8 NLPM, carrier gas Ar flow rate 4-5 NLPM, powder feed rate 15-20 g / min, and spraying distance 100-105 mm. The metal bonding layer material is one of NiCrAlY, CoCrAlY, and NiCoCrAlY.

[0052] Example 1:

[0053] This invention includes the following steps:

[0054] Step (1) A layer of boride is coated on the surface of the carbide using mechanical alloying technology. The ratio of carbide to boride is SiC:HfB2 = 0.8:0.2. Mechanical alloying parameters: ball-to-material ratio 8:1, rotation speed 200r / min, time 5h.

[0055] Step (2) Weigh the raw materials according to the specified ratio and put them into a ball mill jar for ball milling to obtain a slurry. The mass ratio of coated carbide powder in the slurry is 77%, Al2O3 is 10%, YSZ is 10%, gaseous SiO2 is 3%, deionized water is 1 times the total mass of powder, and polyvinyl alcohol is 1% of the total mass of powder. The ball milling adopts a horizontal ball mill with a ball-to-material ratio of 2:1, a milling speed of 35 r / min, and a ball milling time of 12 h. During spray granulation, the inlet temperature is 300℃, the outlet temperature is 100℃, the spray disc speed is 35 Hz, and the feed speed is 30 rpm. The sintering process of the granulated powder is as follows: hold at 500℃ for 2 h, continue to heat up to 1000℃ and hold for 2 h, the heating rate is 5℃ / min, and then cool down with the furnace under Ar protective atmosphere to obtain a material for special functional layers.

[0056] Step (3) A metal bonding layer is sprayed on the high-temperature alloy substrate after sandblasting. The metal bonding layer material is NiCrAlY, and the spraying process is supersonic flame spraying. The spraying parameters are: oxygen flow rate 1850 SCFH, kerosene flow rate 20 L / h, carrier gas flow rate 10 SCFH, powder feeding rate 4 r / min, spraying distance 350 mm, and the metal bonding layer thickness is 0.1 mm. Then, an intermediate layer is sprayed on the metal bonding layer. The intermediate layer material is a mixture of NiCrAlY and special functional layer material, of which NiCrAlY accounts for 40% by mass and the rest is special functional layer material. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 540 A, main gas Ar flow rate 45 NLPM, auxiliary gas H2 flow rate 6 NLPM, carrier gas Ar flow rate 2 NLPM, powder feeding rate 18 g / min, spraying distance 120 mm, and the intermediate layer thickness is 0.1 mm.

[0057] Step (4) Use atmospheric plasma spraying process to spray special functional layer material onto the intermediate layer. Spraying process parameters: current 590A, main gas Ar flow rate 38NLPM, auxiliary gas H2 flow rate 13NLPM, carrier gas Ar flow rate 3NLPM, powder feeding rate 10g / min, spraying distance 100mm, and special functional layer spraying thickness 1mm.

[0058] Step (5) Spray a silicon layer onto the special functional layer. The silicon layer material is Si powder with a particle size of 20-70 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 580 A, main gas Ar flow rate 43 NLPM, auxiliary gas H2 flow rate 7 NLPM, carrier gas Ar flow rate 3.5 NLPM, powder feed rate 10 g / min, spraying distance 90 mm, and silicon layer spraying thickness 50 μm. Spray a mullite layer onto the silicon layer. The mullite layer material is 3Al2O32SiO2 powder with a particle size of 10-50 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 610 A, main gas Ar flow rate 45 NLPM, auxiliary gas H2 flow rate 7 NLPM, carrier gas Ar flow rate 3 NLPM, powder feed rate 10 g / min, spraying distance 95 mm, and mullite layer spraying thickness 60 μm. A ytterbium silicate layer is sprayed onto a mullite layer. The ytterbium silicate layer material is Yb2Si2O7 powder with a particle size of 10-80μm. The preparation process is atmospheric plasma spraying with the following parameters: current 600A, main gas Ar flow rate 43NLPM, auxiliary gas H2 flow rate 6NLPM, carrier gas Ar flow rate 4NLPM, powder feed rate 15g / min, spraying distance 100mm, and ytterbium silicate layer coating thickness 70μm.

[0059] Example 2:

[0060] This invention includes the following steps:

[0061] Step (1) A layer of boride is coated on the surface of the carbide using mechanical alloying technology. The ratio of carbide to boride is TiC:TaB2 = 0.85:0.15. Mechanical alloying parameters: ball-to-material ratio 9:1, rotation speed 250 r / min, time 8 h.

[0062] Step (2) Weigh the raw materials according to the specified ratio and put them into a ball mill jar for ball milling to obtain a slurry. The mass ratio of coated carbide powder in the slurry is 70%, Al2O3 is 13%, La2Zr2O7 is 13%, gaseous SiO2 is 4%, deionized water is 1.5 times the total mass of powder, and polyvinyl alcohol is 1.5% of the total mass of powder. The ball milling adopts a horizontal ball mill with a ball-to-material ratio of 3:1, a milling speed of 40 r / min, and a ball milling time of 13 h. During spray granulation, the inlet temperature is 310℃, the outlet temperature is 110℃, the spray disc speed is 40 Hz, and the feed speed is 35 rpm. The sintering process of the granulated powder is as follows: hold at 550℃ for 2.5 h, continue to heat up to 1100℃ and hold for 2.5 h, the heating rate is 7℃ / min, and then cool down with the furnace under Ar protective atmosphere to obtain a material for special functional layers.

[0063] Step (3) A metal bonding layer is sprayed on the high-temperature alloy substrate after sandblasting. The metal bonding layer material is CoCrAlY, and the spraying process is supersonic flame spraying. The spraying parameters are: oxygen flow rate 1900 SCFH, kerosene flow rate 22 L / h, carrier gas flow rate 13 SCFH, powder feeding rate 6 r / min, spraying distance 370 mm, and the metal bonding layer thickness is 0.11 mm. Then, an intermediate layer is sprayed on the metal bonding layer. The intermediate layer material is a mixture of CoCrAlY and special functional layer material, of which CoCrAlY accounts for 50% by mass and the rest is special functional layer material. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 550 A, main gas Ar flow rate 47 NLPM, auxiliary gas H2 flow rate 8 NLPM, carrier gas Ar flow rate 3 NLPM, powder feeding rate 20 g / min, spraying distance 130 mm, and the intermediate layer thickness is 0.11 mm.

[0064] Step (4) Using atmospheric plasma spraying, the special functional layer material is sprayed onto the intermediate layer. Spraying process parameters: current 600A, main gas Ar flow rate 41NLPM, auxiliary gas H2 flow rate 14NLPM, carrier gas Ar flow rate 3.5NLPM, powder feeding rate 15g / min, spraying distance 105mm, and special functional layer spraying thickness 1.05mm.

[0065] Step (5) Spray a silicon layer onto the special functional layer. The silicon layer material is Si powder with a particle size of 20-70 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 600 A, main gas Ar flow rate 45 NLPM, auxiliary gas H2 flow rate 8 NLPM, carrier gas Ar flow rate 4 NLPM, powder feed rate 15 g / min, spraying distance 100 mm, and silicon layer spraying thickness 65 μm. Spray a mullite layer onto the silicon layer. The mullite layer material is 3Al2O32SiO2 powder with a particle size of 10-50 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 620 A, main gas Ar flow rate 48 NLPM, auxiliary gas H2 flow rate 8 NLPM, carrier gas Ar flow rate 4 NLPM, powder feed rate 12 g / min, spraying distance 100 mm, and mullite layer spraying thickness 75 μm. A ytterbium silicate layer is sprayed onto a mullite layer. The ytterbium silicate layer material is Yb2Si2O7 powder with a particle size of 10-80μm. The preparation process is atmospheric plasma spraying with the following parameters: current 610A, main gas Ar flow rate 45NLPM, auxiliary gas H2 flow rate 7NLPM, carrier gas Ar flow rate 4.5NLPM, powder feed rate 17g / min, spraying distance 102mm, and ytterbium silicate layer coating thickness 75μm.

[0066] Example 3:

[0067] This invention includes the following steps:

[0068] Step (1) A layer of boride is coated on the surface of the carbide using mechanical alloying technology. The ratio of carbide to boride is Ti3SiC2:ZrB2=0.9:0.1. Mechanical alloying parameters: ball-to-material ratio 10:1, rotation speed 300r / min, time 10h.

[0069] Step (2) Weigh the raw materials according to the specified ratio and put them into a ball mill jar for ball milling to obtain a slurry. The mass ratio of coated carbide powder in the slurry is 63%, Al2O3 is 16%, Gd2Zr2O7 is 16%, gaseous SiO2 is 5%, deionized water is twice the total mass of powder, and polyvinyl alcohol is 2% of the total mass of powder. The ball milling adopts a horizontal ball mill with a ball-to-material ratio of 4:1, a milling speed of 45 r / min, and a ball milling time of 15 h. During spray granulation, the inlet temperature is 320℃, the outlet temperature is 120℃, the spray disc speed is 45 Hz, and the feed speed is 40 rpm. The sintering process of the granulated powder is as follows: hold at 600℃ for 3 h, continue to heat up to 1200℃ and hold for 3 h, the heating rate is 10℃ / min, and then cool down with the furnace under Ar protective atmosphere to obtain a material for special functional layers.

[0070] Step (3) A metal bonding layer is sprayed on the high-temperature alloy substrate after sandblasting. The metal bonding layer material is NiCoCrAlY, and the spraying process is supersonic flame spraying. The spraying parameters are: oxygen flow rate 1950 SCFH, kerosene flow rate 25 L / h, carrier gas flow rate 15 SCFH, powder feeding rate 8 r / min, spraying distance 400 mm, and the metal bonding layer thickness is 0.12 mm. Then, an intermediate layer is sprayed on the metal bonding layer. The intermediate layer material is a mixture of NiCoCrAlY and special functional layer material, of which NiCoCrAlY accounts for 60% by mass and the rest is special functional layer material. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 560 A, main gas Ar flow rate 50 NLPM, auxiliary gas H2 flow rate 10 NLPM, carrier gas Ar flow rate 4 NLPM, powder feeding rate 22 g / min, spraying distance 140 mm, and the intermediate layer thickness is 0.12 mm.

[0071] Step (4) Use atmospheric plasma spraying process to spray special functional layer material onto the intermediate layer. Spraying process parameters: current 620A, main gas Ar flow rate 45NLPM, auxiliary gas H2 flow rate 15NLPM, carrier gas Ar flow rate 4NLPM, powder feeding rate 20g / min, spraying distance 110mm, special functional layer spraying thickness 1.1mm.

[0072] Step (5) Spray a silicon layer onto the special functional layer. The silicon layer material is Si powder with a particle size of 20-70 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 620 A, main gas Ar flow rate 47 NLPM, auxiliary gas H2 flow rate 10 NLPM, carrier gas Ar flow rate 4.5 NLPM, powder feed rate 20 g / min, spraying distance 110 mm, and silicon layer spraying thickness 80 μm. Spray a mullite layer onto the silicon layer. The mullite layer material is 3Al2O32SiO2 powder with a particle size of 10-50 μm. The preparation process is atmospheric plasma spraying, with the following spraying parameters: current 630 A, main gas Ar flow rate 50 NLPM, auxiliary gas H2 flow rate 9 NLPM, carrier gas Ar flow rate 5 NLPM, powder feed rate 15 g / min, spraying distance 105 mm, and mullite layer spraying thickness 90 μm. A ytterbium silicate layer is sprayed onto a mullite layer. The ytterbium silicate layer material is Yb2Si2O7 powder with a particle size of 10-80μm. The preparation process is atmospheric plasma spraying with the following parameters: current 620A, main gas Ar flow rate 48NLPM, auxiliary gas H2 flow rate 8NLPM, carrier gas Ar flow rate 5NLPM, powder feed rate 20g / min, spraying distance 105mm, and ytterbium silicate layer coating thickness 80μm.

[0073] Table 1. Thermal shock resistance of the multilayer special functional coatings prepared in the examples.

[0074]

[0075] Table 2. Temperature resistance of the multilayer special functional coatings prepared in the examples.

[0076]

[0077]

[0078] Table 3 shows the oxidative weight gain per unit area of ​​the multilayer special functional coatings prepared in the examples.

[0079]

Claims

1. A high-temperature resistant, long-life carbide multilayer special functional coating, characterized in that, The multilayer special functional coating consists of a metal bonding layer, an intermediate layer, a special functional layer, a silicon layer, a mullite layer, and a ytterbium silicate layer. The special functional layer comprises coated carbide powder, Al2O3, thermal barrier system material, and fumed SiO2, wherein the mass ratio of coated carbide powder is 63-77%, the mass ratio of Al2O3 is 10-16%, the mass ratio of thermal barrier system material is 10-16%, and the mass ratio of fumed SiO2 is 3-5%.

2. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 1, characterized in that, The multilayer special functional coating consists of a metal bonding layer, an intermediate layer, a special functional layer, a silicon layer, a mullite layer, and a ytterbium silicate layer, with the following thicknesses: metal bonding layer 0.1mm-0.12mm, intermediate layer 0.1mm-0.12mm, special functional layer 1-1.1mm, silicon layer 50μm-80μm, mullite layer 60μm-90μm, and ytterbium silicate layer 70μm-80μm.

3. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 1, characterized in that, The thermal barrier system material is one or more of YSZ, La2Zr2O7, and Gd2Zr2O7.

4. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 1, characterized in that, The method for preparing the special functional layer spray powder includes the following steps: (1) Carbide coating: A layer of boride is coated on the surface of the carbide using mechanical alloying technology; (2) Preparation of spray powder: 1) Slurry preparation: The coated carbide powder, Al2O3, thermal barrier system material, gaseous SiO2, polyvinyl alcohol and deionized water are weighed according to the specified ratio and put into a ball mill jar for ball milling; 2) Spherical powder is prepared using a spray granulator: spray granulator inlet temperature 300-320℃, outlet temperature 100-120℃, spray disc rotation speed 35-45Hz, and feed speed 30-40rpm; 3) Granulated powder sintering: The equipment used for granulated powder sintering is an atmosphere sintering furnace. The sintering process is as follows: hold at 500-600℃ for 2-3 hours, continue to heat up to 1000-1200℃ and hold for 2-3 hours, with a heating rate of 5-10℃ / min, and cool down with the furnace. Ar protective atmosphere.

5. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 4, characterized in that, In step (1), the carbide is one of SiC, TiC, or Ti3SiC2; the boride is one of HfB2, TaB2, or ZrB2.

6. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 4, characterized in that, The specific method of carbide coating in step (1) is as follows: place the carbide and boride on a planetary ball mill and ball mill them with a ball-to-material ratio of 8-10:1, a rotation speed of 200-300 r / min, and a time of 5-10 h; the ratio of carbide to boride is 0.8-0.9:0.1-0.

2.

7. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 4, characterized in that, In step (2), the mass of deionized water is 1-2 times the total mass of the powder, and the mass of polyvinyl alcohol is 1-2% of the total mass of the powder.

8. The high-temperature resistant, long-life carbide multilayer special functional coating according to claim 4, characterized in that, Step (2) The ball milling is carried out using a horizontal ball mill with a ball-to-material ratio of 2-4:1, a mill speed of 35-45 r / min, and a ball milling time of 12-15 h.

9. The method for preparing a high-temperature resistant, long-life carbide multilayer special functional coating according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Apply a metal bonding layer to the high-temperature alloy substrate after sandblasting; The spraying process is supersonic flame spraying, and the spraying parameters are: oxygen flow rate 1850-1950 SCFH, kerosene flow rate 20-25 L / h, carrier gas flow rate 10-15 SCFH, powder feeding rate 4-8 r / min, and spraying distance 350-400 mm. (2) Spray an intermediate layer on the metal bonding layer. The intermediate layer material is a mixture of bonding layer material and special functional layer material. The bonding layer material accounts for 40%-60% of the mass, and the rest is special functional layer material. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 540-560A, main gas Ar flow rate 45-50NLPM, auxiliary gas H2 flow rate 6-10NLPM, carrier gas Ar flow rate 2-4NLPM, powder feeding rate 18-22g / min, and spraying distance 120-140mm. (3) Using atmospheric plasma spraying process, the special functional layer is sprayed onto the intermediate layer with spray powder. Spraying process parameters: current 590-620A, main gas Ar flow rate 38-45NLPM, auxiliary gas H2 flow rate 13-15NLPM, carrier gas Ar flow rate 3-4NLPM, powder feeding rate 10-20g / min, spraying distance 100-110mm; (4) Spraying a silicon layer on the special functional layer, wherein the silicon layer material is Si powder with a particle size of 20-70μm; the preparation process is atmospheric plasma spraying, and the spraying parameters are: current 580-620A, main gas Ar flow rate 43-47NLPM, auxiliary gas H2 flow rate 7-10NLPM, carrier gas Ar flow rate 3.5-4.5NLPM, powder feeding rate 10-20g / min, and spraying distance 90-110mm; (5) Spray a mullite layer on the silicon layer. The mullite layer material is 3Al2O32SiO2 powder with a particle size of 10-50μm. The preparation process is atmospheric plasma spraying. The spraying parameters are: current 610-630A, main gas Ar flow rate 45-50NLPM, auxiliary gas H2 flow rate 7-9NLPM, carrier gas Ar flow rate 3-5NLPM, powder feeding rate 10-15g / min, and spraying distance 95-105mm. (6) Spraying a ytterbium silicate layer onto the mullite layer, wherein the ytterbium silicate layer material is Yb2Si2O7 powder with a particle size of 10-80μm; the preparation process is atmospheric plasma spraying, and the spraying parameters are: current 600-620A, main gas Ar flow rate 43-48NLPM, auxiliary gas H2 flow rate 6-8NLPM, carrier gas Ar flow rate 4-5NLPM, powder feeding rate 15-20g / min, and spraying distance 100-105mm.

10. The method for preparing a high-temperature resistant, long-life carbide multilayer special functional coating according to claim 9, characterized in that, The metal bonding layer material is one of NiCrAlY, CoCrAlY, and NiCoCrAlY.

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