An apparatus and method for electrically pulse-driven melt infiltration and sintering of gradient blade tip wear-resistant coatings

Abstract

An apparatus and method for electrically pulse-driven melt infiltration sintering of a gradient blade tip wear-resistant coating. The apparatus comprises a high-temperature furnace (3), an argon gas tank (1), a pulsed DC power supply (4), and a temperature controller (2). The coating preparation method involves sequentially placing a high-temperature alloy, a high-melting-point alloy powder reinforced with ceramic particles, wear-resistant particles, and a self-fluxing alloy powder into the high-temperature furnace to form a coating sample. Argon gas is introduced into the argon gas tank. Under argon protection, an electrode lifting mechanism presses the electrode down into the alloy powder and maintains a certain pressure. Subsequently, under high temperature and pulsed current, the gradient blade tip wear-resistant coating is obtained through electrically pulse-driven melt infiltration sintering. This invention introduces pulsed current during high-temperature melt infiltration sintering, enabling the alloy melt to overcome melt infiltration resistance and quickly complete the preparation of the gradient blade tip wear-resistant coating in one go, greatly improving efficiency and quality.

Description

Technical Field

[0001] This invention relates to an apparatus and method for electrically pulse-driven melt infiltration sintering of gradient blade tip wear-resistant coatings, belonging to the field of protective coating preparation. Background Technology

[0002] Improving the sealing performance of high-temperature turbine sections in aero-engines / gas turbines, reducing fuel consumption and carbon emissions, while simultaneously meeting the dual requirements of surface hardness of the blade tip coating and the bonding between the coating and the substrate, has become a new focus. This has led to the development of composite blade tip wear-resistant coatings (hereinafter referred to as gradient blade tip wear-resistant coatings) with a gradient reduction in ceramic particle content from the surface to the coating / substrate interface.

[0003] Given the unique morphology of wear-resistant particles and the harsh working environment of this type of coating, conventional coating preparation methods are insufficient, while the melt infiltration sintering process based on composite powders demonstrates significant advantages. However, due to the poor wettability between the molten metal and ceramic particles, and the increased melt flow resistance as the molten metal alternates with the contact surfaces in the metal / ceramic composite, "blockage" often occurs, preventing the effective bonding between the coating components.

[0004] To address a key issue, researchers have proposed various solutions, such as increasing the temperature, modifying the ceramic surface, and adding active elements, achieving certain results and playing an important role in the preparation of bulk composite materials from uniform metal or ceramic matrices through molten metal infiltration and sintering. However, the range for increasing the temperature is limited, as excessively high temperatures may damage the matrix; while ceramic surface modification and the addition of active elements mainly depend on the compatibility of the metal / ceramic system, limiting the range of options.

[0005] Applying an auxiliary current is another approach, which is more adaptable and can significantly shorten the melting and infiltration time, improve wetting, and accelerate the interfacial reaction, thus having great application potential.

[0006] Studying the influence of electrical pulses on melting and infiltration behavior, especially the mechanism by which electrical pulses improve the wettability and interfacial reaction of molten metal in metal / ceramic gradient composites, is of great significance. However, there are currently no commercially available devices or methods for preparing gradient blade tip wear-resistant coatings by pulse-driven melting and infiltration sintering. Summary of the Invention

[0007] The purpose of this invention is to enable the alloy melt to overcome melting resistance and quickly complete the preparation of gradient blade tip wear-resistant coating in one go, thereby greatly improving the efficiency and quality of preparing gradient blade tip wear-resistant coating. This invention proposes an apparatus and method for electrically pulse-driven melting and sintering of gradient blade tip wear-resistant coating.

[0008] The technical solution implemented by the present invention is as follows: an apparatus for electrically pulse-driven melting and sintering of gradient blade tip wear-resistant coating, comprising an argon gas tank, a temperature controller, a high-temperature furnace, and a pulsed DC power supply, wherein the high-temperature furnace comprises heating and heat preservation components; characterized in that the high-temperature furnace further comprises a gas protection chamber, a conductive mechanism, a gas guiding mechanism, and an electrode lifting mechanism.

[0009] The gas guiding mechanism includes a copper block, a gas guiding pipe, and a gas guiding iron column. The copper block is installed in the center of the bottom of the high-temperature furnace body. The copper block with a gas guiding channel inside is threaded to the gas guiding pipe through a side threaded hole. The copper block is threaded to the gas guiding iron column with a gas guiding channel inside through a top threaded hole, thus forming the gas guiding mechanism of the high-temperature furnace. Argon gas enters the high-temperature furnace in sequence through the gas guiding pipe, the copper block, and the gas guiding iron column.

[0010] The conductive mechanism includes an upper electrode and a lower electrode. The upper electrode includes a graphite rod, thermocouple B, and a porous corundum tube. The lower electrode includes a graphite pad, a gas-conducting iron column, a copper block, and a conductive copper rod. The copper block is threaded to the conductive copper rod through a side threaded hole and to the gas-conducting iron column through a top threaded hole. A graphite pad is embedded in the top of the gas-conducting iron column. The graphite pad, gas-conducting iron column, copper block, and conductive copper rod together constitute the lower electrode of the conductive mechanism of the high-temperature furnace. The lower electrode is embedded inside the high-temperature furnace through a through hole in the center of the bottom of the furnace body. The graphite rod and thermocouple B are inserted into the porous corundum tube and bonded with high-temperature adhesive, forming the upper electrode of the conductive mechanism of the high-temperature furnace. The graphite rod is used for conduction, and thermocouple B is used to monitor the resistance heat inside the coating sample during discharge, which facilitates the adjustment of process parameters. The upper electrode is inserted into the high-temperature furnace through a through hole in the center of the furnace cover. Pulsed DC current enters the high-temperature furnace through the upper and lower electrodes of the conductive mechanism.

[0011] The gas protection chamber includes a high-temperature furnace body, a high-temperature glass tube, and a high-temperature furnace cover; the bottom of the high-temperature glass tube is embedded in a groove in the center of the top of the high-temperature furnace body, and the top of the high-temperature glass tube is embedded in a groove in the center of the bottom of the high-temperature furnace cover.

[0012] The electrode clamp and the lead screw lifting platform are connected by threads to form the electrode lifting mechanism of the high-temperature furnace. The electrode lifting mechanism is embedded in the top of the furnace cover of the high-temperature furnace, realizing the up and down movement of the upper electrode of the conductive mechanism of the high-temperature furnace in the gas protection chamber of the high-temperature furnace.

[0013] The high-temperature furnace body and furnace cover are equipped with an insulation layer, which is then surrounded by an outer shell and a base. Multiple layers of silicon carbide rods are horizontally arranged inside the furnace body, serving as heating elements to raise the furnace chamber temperature to the set temperature. A thermocouple A is installed inside the furnace body, and is led out through the furnace body, insulation layer, and outer shell via wires to a temperature controller for monitoring the furnace chamber temperature. Through-holes are located on both sides of the furnace body, with high-temperature glass plates embedded within them, forming observation windows for the high-temperature furnace.

[0014] A method for electrically pulse-driven melt infiltration and sintering of a gradient blade tip wear-resistant coating, employing the aforementioned electrically pulse-driven melt infiltration and sintering device for the gradient blade tip wear-resistant coating, comprises the following steps:

[0015] (1) Prepare high-melting-point alloy powder and self-fluxing alloy powder with ceramic particle gradient reinforcement; remove the oxide layer on the surface of the high-temperature alloy block to be coated, and clean it to remove oil and impurities;

[0016] (2) An electric pulse driven melting and sintering gradient blade tip wear-resistant coating equipment is used. After the upper electrode is raised to the top of the high temperature furnace cover by the electrode lifting mechanism of the high temperature furnace, the high temperature alloy block is placed in the gas protection chamber of the high temperature furnace through the through hole of the high temperature furnace cover.

[0017] (3) The high-melting-point alloy powder with ceramic particle gradient reinforcement is placed on the upper surface of the high-temperature alloy block through the through hole of the high-temperature furnace cover. Then, the high-melting-point alloy powder with ceramic particle gradient reinforcement is evenly spread on the surface of the high-temperature alloy block by the powder presser. Then, the wear-resistant particles are inserted into the high-melting-point alloy powder layer with ceramic particle gradient reinforcement according to the arrangement requirements through the through hole of the high-temperature furnace cover. The particles are exposed to a certain height and assembled into a coating substrate. Finally, the self-fluxing alloy powder is placed on the surface of the coating substrate through the through hole of the high-temperature furnace cover. The self-fluxing alloy powder is then evenly spread on the surface of the coating substrate by the powder presser and assembled into a coating sample. The thickness of each powder layer is controlled between 0.1 and 0.4 mm.

[0018] (4) The electrode lifting mechanism presses the upper electrode down and inserts the self-fluxing alloy powder through the through hole of the furnace cover at the top of the high temperature furnace and maintains a certain pressure. The high temperature furnace and temperature controller are turned on, the temperature parameters are set, the argon tank is turned on and argon gas is introduced. The argon gas flow rate is 5-30 L / min. Under the protection of argon gas, the high temperature furnace starts to heat up to 800-1400℃ and keeps it at that temperature.

[0019] (5) When the high temperature furnace is heated to 800~1400℃ and enters the heat preservation stage, turn on the pulse DC power supply in the electric pulse drive melting infiltration sintering gradient blade tip wear-resistant coating equipment, set the electric pulse parameters, and discharge through the conductive mechanism of the high temperature furnace. Under the action of high temperature of 800~1400℃ and pulse current, the self-fluxing alloy powder melts and gradually infiltrates into the high melting point alloy powder layer reinforced by ceramic particles. After the heat preservation is completed, the electrode is pulled back before the self-fluxing alloy in the molten state solidifies, and then the power supply is disconnected and the temperature is quickly cooled to room temperature. The self-fluxing alloy solidifies to form a gradient blade tip wear-resistant coating.

[0020] The metal-ceramic particle mixture powder comprises 20–70 wt.% of the coating; the self-fluxing alloy powder has a particle size of 45–150 μm and comprises 30–80 wt.% of the coating; the high-melting-point alloy powder in the metal-ceramic particle mixture powder has a higher melting point than the self-fluxing alloy powder, the high-melting-point alloy powder has a particle size of 45–150 μm, and its content is 20–80 wt.% of the metal-ceramic particle mixture powder; the ceramic particles in the metal-ceramic particle mixture powder are carbides, oxides, or... The nitride ceramic particles have a particle size of 1–50 μm and a ceramic particle content of 20–80 wt.% of the metal-ceramic particle mixed powder. Furthermore, from the high-temperature alloy substrate to the coating surface, the ceramic particle content in the metal-ceramic particle mixed powder layer increases by a percentage of 5–10 wt.% per 0.1 mm. The wear-resistant particles are carbides, oxides, or nitrides, with irregular shapes and a particle size of 50–300 μm. The exposed height of the wear-resistant particles implanted on the coating surface is controlled between 20% and 80% of the particle size.

[0021] The temperature parameters are as follows: heating rate 10-20℃ / min to 800-1400℃, holding at that temperature for 0.5-1 hour; then disconnecting the power supply and rapidly cooling to room temperature. The electrical pulse parameters are as follows: discharge voltage 10-200V, discharge current 0.01-100A, discharge frequency 1-1000Hz.

[0022] The beneficial effects of this invention are as follows: In addition to improving the methods for preparing gradient blade tip wear-resistant coatings by increasing temperature, modifying ceramic surface, and adding active elements, this invention provides a new apparatus and method for preparing gradient blade tip wear-resistant coatings by melt infiltration sintering. This effectively avoids the disadvantages of excessively high temperature causing matrix damage, ceramic surface modification, and the addition of active elements depending on the compatibility of the metal / ceramic system, which limits the range of choices.

[0023] To address the issues of poor wetting and high melting resistance during the melting and sintering process of gradient wear-resistant sealing coatings for high-temperature single-crystal turbine blade tips, this invention introduces pulsed current into the coating preparation process. This effectively improves the wettability of the molten metal across the metal / ceramic cross-surface dynamic wetting, preventing the coating from failing to form a bond due to "flow blockage." The electric pulse promotes the rapid flow of the molten metal into the micro-gap inside the ceramic particles, generating a significant interfacial reaction and increasing the bonding force between the coating matrix and the ceramic particles. During the electric pulse-driven melting and sintering process of the gradient wear-resistant coating for blade tips, the reaction between the low-melting-point alloy and the metal-based ceramic composite powder also consumes the demelting elements, causing them to generate a high-temperature hard phase, thereby achieving the effect of low-temperature preparation and high-temperature service.

[0024] The apparatus and method of the present invention introduce pulsed current while performing high-temperature melting and sintering, which effectively improves the wettability of the metal melt between the contact surfaces of the metal / ceramic composite material, enabling the alloy melt to overcome melting resistance and quickly complete the preparation of the gradient blade tip wear-resistant coating in one go, greatly improving the efficiency and quality of the preparation of the gradient blade tip wear-resistant coating. Attached Figure Description

[0025] Figure 1 A schematic diagram of the principle of an electric pulse driven melt infiltration sintering gradient blade tip wear-resistant coating device;

[0026] Figure 2 This is a schematic diagram of the high-temperature furnace structure;

[0027] Figure 3 This is a cross-sectional view (AA) of the high-temperature furnace structure.

[0028] Figure 4 A schematic diagram illustrating the principle of an electrically pulse-driven melt infiltration and sintering method for gradient blade tip wear-resistant coatings.

[0029] In the diagram: 1 is an argon gas cylinder; 2 is a temperature controller; 3 is a high-temperature furnace; 4 is a pulsed DC power supply; 11 is a self-fluxing alloy powder; 12 is wear-resistant particles; 13 is ceramic particles; 14 is a high-melting-point alloy powder; 15 is a high-temperature alloy; 16 is a gradient blade tip wear-resistant coating; 17 is a graphite electrode; 301 is the high-temperature furnace body; 302 is a graphite pad; 303 is a silicon carbide rod; 304 is a gas guide iron column; 305 is a copper block; 306 is a gas guide pipe; 307 is a conductive copper rod; 308 is thermocouple A; 309 is a high-temperature glass tube; 310 is the high-temperature furnace cover; 311 is a porous corundum tube; 312 is a graphite rod; 313 is a thermocouple B; 314 is an electrode clamp; 315 is a lead screw lifting platform; 316 is a high-temperature glass plate; 317 is a coating sample; 318 is a heat insulation layer; 319 is the outer shell and base. Detailed Implementation

[0030] The specific embodiments of the present invention are as follows:

[0031] This embodiment presents an apparatus and method for electrically pulse-driven melt infiltration and sintering of gradient blade tip wear-resistant coatings, the specific implementation of which is as follows:

[0032] (1) Prepare high melting point alloy powder (particle size 45-150μm) and self-fluxing alloy powder (particle size 45-150μm) with ceramic particles (particle size 1-50μm) gradient reinforcement; remove the oxide layer on the surface of the high temperature alloy block to be coated by sanding with sandpaper, and clean with anhydrous alcohol to remove surface oil and impurities;

[0033] (2) An electric pulse driven melting and infiltration sintering gradient blade tip wear-resistant coating device is adopted. After the upper electrode is raised to the top of the high temperature furnace cover by the electrode lifting mechanism of the high temperature furnace, the high temperature alloy is placed in the gas protection chamber of the high temperature furnace through the through hole of the high temperature furnace cover.

[0034] (3) Through the through holes of the high-temperature furnace cover, the high-melting-point alloy powder with ceramic particle gradient reinforcement is uniformly spread on the surface of the high-temperature alloy block. Then, wear-resistant particles (particle size of 50-300μm) are embedded into the high-melting-point alloy powder with ceramic particle gradient reinforcement according to the arrangement requirements. The particles are exposed to a certain height, and the exposed height is controlled between 20% and 80% of the particle size. The coating substrate is assembled. Finally, the self-fluxing alloy powder is uniformly spread on the surface of the coating substrate to assemble the coating sample. The thickness of each powder layer is controlled between 0.1 and 0.4 mm.

[0035] (4) The electrode lifting mechanism presses the upper electrode down into the self-fluxing alloy powder and maintains a certain pressure. The high-temperature furnace and temperature controller are turned on, the temperature parameters are set, the argon gas tank is turned on and argon gas is introduced. The argon gas flow rate is 5-30 L / min. Under the protection of argon gas, the high-temperature furnace starts to heat up. The temperature parameters are: heating rate 10-20℃ / min, heating to 800-1400℃, holding for 0.5-1 hour. After the holding is completed, the power is turned off and the furnace is quickly cooled to room temperature.

[0036] (5) When the high temperature furnace is heated to 800~1400℃ and enters the heat preservation stage, turn on the pulse DC power supply in the electric pulse drive melting infiltration sintering gradient blade tip wear-resistant coating device, and set the electric pulse parameters. The electric pulse parameters are discharge voltage 10~200V, discharge current 0.01~100A, and discharge frequency 1~1000Hz. The pulse DC power supply discharges through the conductive mechanism of the high temperature furnace. Under the action of high temperature of 800~1400℃ and pulse current, the self-fluxing alloy powder melts and gradually infiltrates into the high melting point alloy powder coating with ceramic particle gradient enhancement. After the heat preservation is completed, the electrode is pulled back before the self-fluxing alloy in the molten state solidifies, and then the power supply is disconnected and the temperature is quickly cooled to room temperature. The self-fluxing alloy solidifies to form a gradient blade tip wear-resistant coating.

[0037] Example 1

[0038] In this embodiment, a NiCoCrAlYTa alloy powder (particle size 45~150μm) and a NiCrSi self-fluxing alloy powder (particle size 45~150μm) are prepared with TiC ceramic particles (particle size 10~50μm) gradient reinforcement.

[0039] The metal substrate was selected from single-crystal high-temperature alloy PWA1483. The oxide layer on the surface of the metal substrate was removed by sandpaper, and oil and impurities were removed by ultrasonic cleaning with anhydrous ethanol. Then, an electric pulse driven melting and sintering gradient blade tip wear-resistant coating device was used. The metal substrate was placed into the gas protection chamber through the through hole of the high-temperature furnace cover. Then, NiCoCrAlYTa alloy powder with ceramic particle gradient reinforcement was uniformly spread on the surface of the single-crystal high-temperature alloy block. Then, Al2O3 ceramic wear-resistant particles of 150~200 micrometers were embedded into the NiCoCrAlYTa alloy powder layer with ceramic particle gradient reinforcement according to the arrangement requirements. The particles were exposed to a certain height, which was controlled between 50% and 80% of the particle size. The coating substrate was assembled. Then, NiCrSi self-fluxing alloy powder was uniformly spread on the surface of the coating substrate to assemble the coating sample. The NiCoCrAlYTa alloy powder layer was 0.3 mm thick, and the NiCrSi self-fluxing alloy powder layer was 0.2 mm thick.

[0040] The electrode lifting mechanism presses the upper electrode down into the NiCrSi self-fluxing alloy powder and maintains a certain pressure. The high-temperature furnace and temperature controller are turned on, the temperature parameters are set, and the argon gas tank is turned on to introduce argon gas. The argon gas flow rate is 18L / min. Under the protection of argon gas, the high-temperature furnace begins to heat up. Its temperature parameters are set as follows: heating rate 15℃ / min to heat to 1200℃, and holding at that temperature for 0.5 hours.

[0041] When the high-temperature furnace reaches 1200℃ and enters the heat preservation stage, the pulsed DC power supply in the electric pulse driven melting and infiltration sintering gradient blade tip wear-resistant coating device is turned on, and the electric pulse parameters are set as follows: discharge voltage 40V, discharge current 5A, and discharge frequency 20Hz. The pulsed DC power supply discharges through the conductive mechanism of the high-temperature furnace. Under the action of the high temperature of 1200℃ and the pulsed current, the NiCrSi self-fluxing alloy powder melts and gradually infiltrates into the NiCoCrAlYTa alloy powder coating reinforced by the ceramic particle gradient. After the heat preservation is completed, the electrode is withdrawn before the molten NiCrSi self-fluxing alloy solidifies, and then the power supply is disconnected and the material is quickly cooled to room temperature. The NiCrSi self-fluxing alloy solidifies to form the gradient blade tip wear-resistant coating.

[0042] Example 2

[0043] In this embodiment, NiCoCrAlYTa alloy powder (particle size 45~150μm) and NiCrBSi self-fluxing alloy powder (particle size 45~150μm) are prepared with gradient reinforcement of ZrO2 ceramic particles (particle size 20~50μm).

[0044] The metal substrate was selected from the high-temperature alloy Inconel 625. The oxide layer on the surface of the metal substrate was removed by sandpaper, and oil and impurities were removed by ultrasonic cleaning with anhydrous ethanol. Then, an electric pulse driven melting and sintering gradient blade tip wear-resistant coating device was used. The metal substrate was placed into the gas protection chamber through the through hole of the high-temperature furnace cover. Then, NiCoCrAlYTa alloy powder with ceramic particle gradient reinforcement was uniformly spread on the surface of the single crystal high-temperature alloy block. Then, Al2O3 ceramic wear-resistant particles of 150~250 micrometers were embedded into the NiCoCrAlYTa alloy powder layer with ceramic particle gradient reinforcement according to the arrangement requirements. The particles were exposed to a certain height, which was controlled between 50% and 80% of the particle size. The coating substrate was assembled. Then, NiCrBSi self-fluxing alloy powder was uniformly spread on the surface of the coating substrate to assemble the coating sample. The NiCoCrAlYTa alloy powder layer was 0.2 mm thick, and the NiCrBSi self-fluxing alloy powder layer was 0.2 mm thick.

[0045] The electrode lifting mechanism presses the upper electrode down into the NiCrBSi self-fluxing alloy powder and maintains a certain pressure. The high-temperature furnace and temperature controller are turned on, the temperature parameters are set, and the argon gas tank is turned on to introduce argon gas. The argon gas flow rate is 15L / min. Under the protection of argon gas, the high-temperature furnace begins to heat up. Its temperature parameters are set as follows: heating rate 10℃ / min to 1100℃, and holding at that temperature for 0.6 hours.

[0046] When the high-temperature furnace reaches 1100℃ and enters the heat preservation stage, the pulsed DC power supply in the electric pulse driven melting and infiltration sintering gradient blade tip wear-resistant coating device is turned on, and the electric pulse parameters are set as follows: discharge voltage 40V, discharge current 6A, and discharge frequency 10Hz. The pulsed DC power supply discharges through the conductive mechanism of the high-temperature furnace. Under the action of the high temperature of 1100℃ and the pulsed current, the NiCrBSi self-fluxing alloy powder melts and gradually infiltrates into the NiCoCrAlYTa alloy powder coating reinforced by the ceramic particle gradient. After the heat preservation is completed, the electrode is withdrawn before the molten NiCrBSi self-fluxing alloy solidifies, and then the power supply is disconnected and the material is quickly cooled to room temperature. The NiCrBSi self-fluxing alloy solidifies to form the gradient blade tip wear-resistant coating.

[0047] Example 3

[0048] In this embodiment, a NiCoCrAlY alloy powder (particle size 45~150μm) and a NiCrBSi self-fluxing alloy powder (particle size 45~150μm) are prepared with TaC ceramic particles (particle size 10~50μm) gradient reinforcement.

[0049] The metal substrate is selected from high-temperature alloy DZ125L. The oxide layer on the surface of the metal substrate is removed by sandpaper, and oil and impurities are removed by ultrasonic cleaning with anhydrous ethanol. Then, an electric pulse driven melting and sintering gradient blade tip wear-resistant coating device is used to place the metal substrate into the gas protection chamber through the through hole of the high-temperature furnace cover. Then, NiCoCrAlY alloy powder with ceramic particle gradient reinforcement is uniformly spread on the surface of the single crystal high-temperature alloy block. Then, SiC ceramic wear-resistant particles of 150~200 micrometers are embedded into the NiCoCrAlY alloy powder layer with ceramic particle gradient reinforcement according to the arrangement requirements. The particles are exposed to a certain height, which is controlled between 50% and 80% of the particle size, and assembled into a coating substrate. Then, NiCrBSi self-fluxing alloy powder is uniformly spread on the surface of the coating substrate to assemble the coating sample. The NiCoCrAlY alloy powder layer is 0.3 mm thick, and the NiCrBSi self-fluxing alloy powder layer is 0.3 mm thick.

[0050] The electrode lifting mechanism presses the upper electrode down into the NiCrBSi self-fluxing alloy powder and maintains a certain pressure. The high-temperature furnace and temperature controller are turned on, the temperature parameters are set, and the argon gas tank is turned on to introduce argon gas. The argon gas flow rate is 18L / min. Under the protection of argon gas, the high-temperature furnace begins to heat up. Its temperature parameters are set as follows: heating rate 15℃ / min to 1100℃, and holding for 0.5 hours.

[0051] When the high-temperature furnace reaches 1100℃ and enters the heat preservation stage, the pulsed DC power supply in the electric pulse driven melting and infiltration sintering gradient blade tip wear-resistant coating device is turned on, and the electric pulse parameters are set as follows: discharge voltage 50V, discharge current 6A, and discharge frequency 30Hz. The pulsed DC power supply discharges through the conductive mechanism of the high-temperature furnace. Under the action of the high temperature of 1100℃ and the pulsed current, the NiCrBSi self-fluxing alloy powder melts and gradually infiltrates into the NiCoCrAlY alloy powder coating reinforced by the ceramic particle gradient. After the heat preservation is completed, the electrode is withdrawn before the molten NiCrBSi self-fluxing alloy solidifies, and then the power supply is disconnected and the material is quickly cooled to room temperature. The NiCrBSi self-fluxing alloy solidifies to form the gradient blade tip wear-resistant coating.

Claims

1. A device for driving electric pulse to infiltrate and sinter gradient tip wear-resistant coating, comprising an argon tank, a temperature controller, a high-temperature furnace, and a pulse direct current power supply, wherein the high-temperature furnace comprises a heating and holding component; characterized in that, The high-temperature furnace further comprises a gas protection chamber, a conductive mechanism, a gas guiding mechanism and an electrode lifting mechanism. The heating and heat preservation component comprises a high-temperature furnace body, a high-temperature furnace cover, a heat preservation layer, an outer shell and a base, and a silicon-carbon rod; the high-temperature furnace body and the high-temperature furnace cover are externally provided with the heat preservation layer, the periphery of the heat preservation layer is wrapped by the outer shell and the base, and the heat preservation layer plays a heat preservation role; the silicon-carbon rod is horizontally provided with multiple layers in the furnace cavity of the high-temperature furnace body, and serves as a heating element to heat the high-temperature furnace hearth temperature to a set temperature; the high-temperature furnace body is further provided with a thermocouple A inside, which is led out through the high-temperature furnace body, the heat preservation layer and the outer shell by wires, and is connected to a temperature controller to monitor the hearth temperature; The gas guiding mechanism comprises a copper block, a gas guiding pipe and a gas guiding iron column; the copper block with a gas guiding channel inside is threadedly connected with the gas guiding pipe through a side threaded hole, and the copper block is threadedly connected with the gas guiding iron column with a gas guiding channel inside through a top threaded hole; argon gas enters the high-temperature furnace in sequence through the gas guiding pipe, the copper block and the gas guiding iron column; The conductive mechanism comprises an upper electrode and a lower electrode; the upper electrode comprises a graphite rod, a thermocouple B and a porous corundum pipe; the lower electrode comprises a graphite pad, a gas guiding iron column, a copper block and a conductive copper rod; the copper block is threadedly connected with the conductive copper rod through a side threaded hole and threadedly connected with the gas guiding iron column through a top threaded hole, and the gas guiding iron column is embedded with the graphite pad at the top; the lower electrode is embedded in the high-temperature furnace through a through hole at the bottom of the high-temperature furnace body; the graphite rod and the thermocouple B are inserted into the porous corundum pipe and fixed by high-temperature glue, and constitute the upper electrode of the conductive mechanism of the high-temperature furnace, wherein the graphite rod is used for conducting electricity, and the thermocouple B is used for monitoring the resistance heat inside the coating sample during discharging; the upper electrode is inserted into the high-temperature furnace through a through hole of the high-temperature furnace cover, and pulse direct current enters the high-temperature furnace through the upper and lower electrodes of the conductive mechanism of the high-temperature furnace; The gas protection chamber comprises a high-temperature furnace body, a high-temperature glass pipe and a high-temperature furnace cover; the bottom of the high-temperature glass pipe is embedded in a groove at the top of the high-temperature furnace body, and the top of the high-temperature glass pipe is embedded in a groove at the bottom of the high-temperature furnace cover; The electrode clamp is threadedly connected with the screw rod lifting platform, and constitutes the electrode lifting mechanism of the high-temperature furnace, which is embedded at the top of the high-temperature furnace cover, and realizes the up-and-down movement of the upper electrode of the conductive mechanism of the high-temperature furnace in the gas protection chamber of the high-temperature furnace; Through holes are formed at both sides of the high-temperature furnace body, and high-temperature glass pieces are embedded in the through holes to constitute the observation window of the high-temperature furnace; The high-temperature glass pipe and the high-temperature glass piece can resist a temperature of 1500℃.

2. A method of electric pulse driven infiltration and sintering gradient blade tip wear resistant coating using the electric pulse driven infiltration and sintering gradient blade tip wear resistant coating device of claim 1, characterized in that, The method comprises the following steps: (1) configuring ceramic particle gradient reinforced high-melting-point alloy powder and self-fluxing alloy powder; removing the surface oxidation layer of a high-temperature alloy block to be prepared, and cleaning and degreasing and decontaminating the high-temperature alloy block; (2) using an electric pulse driven infiltration sintering gradient blade tip wear-resistant coating equipment, after the upper electrode is lifted to above the high-temperature furnace cover by the electrode lifting mechanism of the high-temperature furnace, the high-temperature alloy block is placed in the gas protection chamber of the high-temperature furnace through the through hole of the high-temperature furnace cover; (3) The ceramic particle gradient reinforced high melting point alloy powder is put on the upper surface of the high temperature alloy block through the high temperature furnace cover hole, and then the ceramic particle gradient reinforced high melting point alloy powder is uniformly coated on the surface of the high temperature alloy block by the powder presser; then the wear-resistant particles are inserted into the ceramic particle gradient reinforced high melting point alloy powder layer according to the arrangement requirement through the high temperature furnace cover hole by using the tweezers, the particles are exposed to a certain height, and a coating substrate is assembled; finally, the self-fluxing alloy powder is put on the surface of the coating substrate through the high temperature furnace cover hole, and then the self-fluxing alloy powder is uniformly coated on the surface of the coating substrate by the powder presser, and a coating sample is assembled; the thickness of each layer of powder is controlled to be between 0.1 and 0.4 mm; (4) The upper electrode is inserted into the self-fluxing alloy powder through the hole of the high temperature furnace top cover by the electrode lifting mechanism and kept under a certain pressure, the high temperature furnace and the temperature controller are turned on, the temperature parameters are set, the argon tank is opened to introduce argon, the argon gas flow is 5-30 L / min, and the high temperature furnace starts to heat to 800-1400 DEG C under the protection of argon. (5) When the high temperature furnace is heated to 800-1400 DEG C and enters the heat preservation stage, the pulse direct current power supply in the electric pulse driven infiltration sintering gradient blade tip wear-resistant coating equipment is turned on, the electric pulse parameters are set, the pulse direct current power supply is discharged through the conductive mechanism of the high temperature furnace, the self-fluxing alloy powder is melted and gradually infiltrated into the ceramic particle gradient reinforced high melting point alloy powder coating under the action of 800-1400 DEG C high temperature and pulse current, and after the heat preservation is finished, the electrode is withdrawn before the self-fluxing alloy is solidified in the molten state, the power supply is disconnected, and the self-fluxing alloy is rapidly cooled to room temperature to form a gradient blade tip wear-resistant coating.

3. A method of electric pulse driven infiltration and sintering gradient tip wear resistant coating according to claim 2, characterized in that, The content of the ceramic particle gradient reinforced high melting point alloy powder in the coating is 20-70 wt.%, the particle size of the self-fluxing alloy powder is 45-150 μm, and the content of the self-fluxing alloy powder in the coating is 30-80 wt.%; the melting point of the high melting point alloy powder in the ceramic particle gradient reinforced high melting point alloy powder is higher than that of the self-fluxing alloy powder, the particle size of the high melting point alloy powder is 45-150 μm, and the content of the high melting point alloy powder is 20-80 wt.% of the ceramic particle gradient reinforced high melting point alloy powder; the ceramic particles in the ceramic particle gradient reinforced high melting point alloy powder are carbides, oxides or nitrides, the particle size of the ceramic particles is 1-50 μm, and the content of the ceramic particles is 20-80 wt.% of the ceramic particle gradient reinforced high melting point alloy powder, and the content of the ceramic particles in the ceramic particle gradient reinforced high melting point alloy powder increases by 5-10 wt.% per 0.1 mm from the high temperature alloy substrate to the surface of the coating; the wear-resistant particles are carbides, oxides or nitrides, have irregular shapes, and have a particle size of 50-300 μm; the exposed height of the wear-resistant particles planted on the surface of the coating is controlled to be between 20% and 80% of the particle size.

4. A method of electric pulse driven infiltration and sintering gradient tip wear resistant coating according to claim 2, characterized in that, The temperature parameters are as follows: the heating rate is 10-20 DEG C / min, the temperature is heated to 800-1400 DEG C, the temperature is kept for 0.5-1 hour, the power supply is disconnected, and the temperature is rapidly cooled to room temperature.

5. A method of electric pulse driven infiltration and sintering gradient tip wear resistant coating according to claim 2, characterized in that, The electric pulse parameters are: discharge voltage 10-200V, discharge current 0.01-100A, discharge frequency 1-1000Hz. The electric pulse parameters are: discharge voltage 10-200V, discharge current 0.01-100A, discharge frequency 1-1000Hz.

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