Preparation method of ordered low-density high-porosity thin film

Abstract

According to the preparation method of the ordered low-density high-porosity thin film, the thin film with gradient components is prepared on the metal surface, meanwhile, screening and optimization of gradient component materials can be achieved, the functional thin film with flexible gradient components and structure permutation and combination is obtained, and the performance of the functional thin film exceeds that of a homogeneous material; according to the method, components of the film are sequentially added through substances in a raw material barrel, the low density is reflected in that laid powder particles suspend in air through airflow and are bonded and combined with one another by means of carried heat, no pressure is applied in the whole process, and then the powder film layer is low in density and high in void due to the fact that powder combination depends on TixAly generated by a thermal explosion reaction; after thermal explosion, the powder particles are in a high-porosity state, and in the laying process, the powder particles are randomly stacked, so that the porosity of the film is large.

Description

Technical Field

[0001] The invention discloses a method for preparing an ordered low-density high-porosity film, belonging to the technical field of thermal processing. Background Art

[0002] Metal foams have a similar organizational structure to other types of foam materials, both of which are composed of solid materials, with a large proportion of pores in the volume. Moreover, metal foams have low density, strong thermal conductivity, high specific stiffness and compressive strength, and can be used in heat exchangers, sound insulation devices, and gas-liquid filters. Studies have shown that metal foams made of titanium, aluminum, and aluminum bronze can be directly 3D printed by using direct energy deposition and adjusting special parameters of the printing process, and the production capacity can be improved by reducing material consumption and creating complex geometric shapes. Therefore, this method is superior to traditional methods in terms of cost and does not require additional preparation and post-processing steps. However, 3D printing requires high energy, special equipment such as lasers, is expensive, and cannot achieve nano-scale particle enhancement. Summary of the invention

[0003] The present invention is designed to address the above-mentioned existing technical situation and provides a method for preparing an ordered low-density high-porosity film. Its purpose is to prepare a film with a gradient composition on the metal surface, and to achieve the screening and optimization of gradient composition materials to obtain functional films with flexible gradient composition and structural arrangement combinations, so that their performance exceeds that of homogeneous materials.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] The device used in the method for preparing an ordered low-density high-porosity film of the present invention includes a W raw material barrel 18, a C raw material barrel 14, a B raw material barrel 10 and surrounding W raw material barrel heating sleeves 19, C raw material barrel heating sleeves 15, and B raw material barrel heating sleeves 9, as well as a W raw material channel 16, a C raw material channel 12, and a B raw material channel 8 for output. The above raw material channels are all provided with vacuum valves, namely, a W raw material channel vacuum valve 17, a C raw material channel vacuum valve 13, and a B raw material channel vacuum valve 11. The above raw material channels are all connected to a mixing barrel 7, and a blasting barrel is provided below the mixing barrel 7. 23, the two are separated by a screen 5, the mixing cylinder 7 and the blasting cylinder 23 are surrounded by a heating sleeve 6, the two sides of the blasting cylinder 23 are connected to the Ti raw material cylinder 22 and the Al raw material cylinder 3 through pipelines, the two sides of the mixing cylinder 7 are respectively provided with a first powder laying pipe 20 and a second powder laying pipe 2, the first powder laying pipe 20 and the second powder laying pipe 2 are respectively installed in the middle of the first powder laying pipe 21 and the second powder laying pipe 4, the outlets of the first powder laying pipe 20 and the second powder laying pipe 2 are arranged above the metal plate 1, and are used to lay powder on the surface of the metal plate 1;

[0006] The steps of preparing an ordered low-density high-porosity film using the above device are as follows:

[0007] Step 1: Raw material preparation

[0008] Place W, C, and B powders in W raw material barrel 18, C raw material barrel 14, and B raw material barrel 10, respectively, and place Ti and Al powders in Ti raw material barrel 22 and Al raw material barrel 3, respectively;

[0009] Start W raw material barrel heating jacket 19, C raw material barrel heating jacket 15, B raw material barrel heating jacket 9

[0010] The left raw material barrel heating jacket 19, the middle raw material barrel heating jacket 15 and the right raw material barrel heating jacket 9,

[0011] Preheating the W, C, and B powders in the W raw material cylinder 18, the C raw material cylinder 14, and the B raw material cylinder 10, the preheating temperature being 800-1400°C;

[0012] Step 2: Raw material blasting

[0013] Start the heating jacket 6, heat the temperature to 1000-1100℃, keep it warm for 30-60min, then input the Ti and Al powders in the Ti raw material barrel 22 and the Al raw material barrel 3 into the blasting barrel 23, increase the power of the heating jacket 6, and raise the temperature in the blasting barrel 23 by another 200℃ within 5-30s, so that the Ti powder and the Al powder react instantly in the blasting barrel 23, and the thermal explosion product TixAly passes through the screen 5 and enters the mixing barrel 7 in an aerosol state.

[0014] Step 3: Mixing of raw materials

[0015] Start the vacuum valve 17 of the W raw material channel, the vacuum valve 13 of the C raw material channel, and the vacuum valve 11 of the B raw material channel, and extract W, C, and B powders from the W raw material cylinder 18, the C raw material cylinder 14, and the B raw material cylinder 10, respectively, and then input them into the mixing cylinder 7 through the W raw material channel 16, the C raw material channel 12, and the B raw material channel 8, respectively. When the W, C, and B powders enter the mixing cylinder 7, they are also in an aerosol state, and the W, C, and B powders in the mixing cylinder 7 are combined with TixAly to form a cohesive state;

[0016] Step 4: Laying out raw materials

[0017] After the W, C, B powders and TixAly in the mixing drum 7 are mixed for 30-60 seconds, the first powder laying pipe vacuum valve 21 and the second powder laying pipe vacuum valve 4 are started to lay the mixture of the W, C, B powders and TixAly in the mixing drum 7 on the surface of the metal plate 1 through the first powder laying pipe 20 and the second powder laying pipe 2 respectively until the thickness reaches the design requirement;

[0018] Step 5: Vacuum sintering

[0019] The metal plate 1 is placed in a vacuum sintering furnace for high temperature sintering at a temperature of 800-1500° C. for 1-2 hours. After cooling, an ordered low-density high-porous film is obtained on the surface of the metal plate 1 .

[0020] In addition, the sieve 5 is used to sieve out powder particles of -400 to -500 mesh.

[0021] In addition, the particle size of the W, C, and B powders is -450 to -600 mesh.

[0022] In addition, the particle size of the Ti and Al powders is -400 to -500 mesh.

[0023] In one implementation, in step 3, the order of inputting W, C, and B powders into the mixing drum 7 is to input W powder and C powder first, and pre-lay TixAly on the surface of the metal plate 1 as a base layer, and wait for the W powder and C powder to combine with TixAly to generate WC+W+C+TixAly, and then input B powder to generate B+TixAly. In step 4, this process makes the powder layer laid on the base layer on the surface of the metal plate 1 have a composition gradient of WC+W+C+TixAly and B+TixAly from bottom to top, respectively. In the subsequent vacuum sintering process in step 5, the two powder layers react chemically to generate BC and WB, so that the final film layer composition gradient is WC+TixAly+W+C+BC+WB+B+TixAly, wherein B, BC, and WB are used as strengthening phases to enhance wear resistance, and the final film layer porosity is more than 90%.

[0024] Furthermore, the thickness of the two powder layers is 200 microns.

[0025] In one embodiment, the powder raw materials in the W raw material barrel 18, the C raw material barrel 14, and the B raw material barrel 10 are replaced with Mg, Al, and Zr, respectively, and TixAly is pre-laid on the surface of the metal plate 1 as a base layer. After the Mg, Al, and Zr powders are combined with TixAly, they are laid on the base layer on the surface of the metal plate 1 with a thickness of 200 microns. The laid powder layer has a composition gradient of Mg+TixAly+Al+Zr from bottom to top. After the vacuum sintering process, the final film layer composition gradient is Mg+TixAly+Al+ZrO, wherein ZrO is a flame retardant phase to enhance heat dissipation and flame retardancy, and the final film layer porosity is above 90%.

[0026] In addition, the diameter ratio of the raw material channel to the raw material cylinder is 1 / 20 to 1 / 30.

[0027] The characteristics and beneficial effects of the technical solution of the present invention are:

[0028] 1. Through the scheme of the present invention, an ordered low-density high-porosity film can be obtained on the metal surface. The order is reflected in the order in which the components of the film are added by the materials in the raw material barrel. The low density is reflected in that the laid powder particles are suspended in the air by the airflow and adhere to each other by the heat they carry. The whole process is pressure-free, so the density of the powder film layer is low. The high voids are due to the powder combination relying on the TixAly generated by the thermal explosion reaction. After the thermal explosion, the powder particles are in a high-porosity state. In addition, during the laying process, the powder particles are randomly stacked, so that the film has a large porosity.

[0029] Second, in the scheme of the present invention, by adjusting the composition of the raw material barrel and the laying position, the three-dimensional structure and local composition of the film material can be controlled, and complex multifunctional film materials with gradient composition and performance can be produced with microscopic spatial resolution. The pore density and size of the film can also be flexibly adjusted;

[0030] 3. The scheme of the present invention is based on the aerosol principle. Multiple atomized materials will be mixed in the mixing barrel. During the laying process, the proportion of various materials will also change dynamically depending on the action of the vacuum valve, ensuring that the 3D structure and local composition of the laying materials can be controlled during high-throughput combined laying, and gradient materials with gradually changing flexibility can be produced with micro-scale spatial resolution;

[0031] Fourth, in the solution of the present invention, nanometer-scale powder particles can also be dispersed in the film as a reinforcing phase to improve the overall performance of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the preparation device described in the technical solution of the present invention DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0034] See attached Figure 1As shown, in this embodiment, the device used in the technical solution of the present invention includes a W raw material barrel 18, a C raw material barrel 14, a B raw material barrel 10 and the surrounding W raw material barrel heating sleeves 19, C raw material barrel heating sleeves 15, and B raw material barrel heating sleeves 9, as well as a W raw material channel 16, a C raw material channel 12, and a B raw material channel 8 for output. The diameter ratio of the above raw material channels to the raw material barrel is 1 / 20 to 1 / 30. Vacuum valves are provided on the above raw material channels, namely, a W raw material channel vacuum valve 17, a C raw material channel vacuum valve 13, and a B raw material channel vacuum valve 11. The above raw material channels are all connected to the mixing barrel 7, and the lower part of the mixing barrel 7 is a blasting barrel 23. , the two are separated by a screen 5, the screen 5 is used to screen out powder particles of -400 to -500 mesh, the mixing cylinder 7 and the blasting cylinder 23 are surrounded by a heating sleeve 6, the two sides of the blasting cylinder 23 are respectively connected to the Ti raw material cylinder 22 and the Al raw material cylinder 3 through pipelines, the two sides of the mixing cylinder 7 are respectively provided with a first powder laying pipe 20 and a second powder laying pipe 2, the first powder laying pipe 20 and the second powder laying pipe 2 are respectively installed in the middle of the first powder laying pipe 21 and the second powder laying pipe 4, the outlets of the first powder laying pipe 20 and the second powder laying pipe 2 are arranged above the metal plate 1, and are used to lay powder on the surface of the metal plate 1;

[0035] The steps of preparing an ordered low-density high-porosity film using the above device are as follows:

[0036] Step 1: Raw material preparation

[0037] The W, C, and B powders are placed in the W raw material cylinder 18, the C raw material cylinder 14, and the B raw material cylinder 10, respectively, and the Ti and Al powders are placed in the Ti raw material cylinder 22 and the Al raw material cylinder 3, respectively; the particle size of the W, C, and B powders is -450 to -600 mesh; in addition, the particle size of the Ti and Al powders is -400 to -500 mesh;

[0038] Start W raw material barrel heating jacket 19, C raw material barrel heating jacket 15, B raw material barrel heating jacket 9

[0039] The left raw material barrel heating jacket 19, the middle raw material barrel heating jacket 15 and the right raw material barrel heating jacket 9,

[0040] Preheating the W, C, and B powders in the W raw material cylinder 18, the C raw material cylinder 14, and the B raw material cylinder 10, the preheating temperature being 800-1400°C;

[0041] Step 2: Raw material blasting

[0042] Start the heating jacket 6, heat the temperature to 1000-1100℃, keep it warm for 30-60min, then input the Ti and Al powders in the Ti raw material barrel 22 and the Al raw material barrel 3 into the blasting barrel 23, increase the power of the heating jacket 6, and raise the temperature in the blasting barrel 23 by another 200℃ within 5-30s, so that the Ti powder and the Al powder react instantly in the blasting barrel 23, and the thermal explosion product TixAly passes through the screen 5 and enters the mixing barrel 7 in an aerosol state.

[0043] Step 3: Mixing of raw materials

[0044] Start the vacuum valve 17 of the W raw material channel, the vacuum valve 13 of the C raw material channel, and the vacuum valve 11 of the B raw material channel, and extract W, C, and B powders from the W raw material cylinder 18, the C raw material cylinder 14, and the B raw material cylinder 10, respectively, and then input them into the mixing cylinder 7 through the W raw material channel 16, the C raw material channel 12, and the B raw material channel 8, respectively. When the W, C, and B powders enter the mixing cylinder 7, they are also in an aerosol state, and the W, C, and B powders in the mixing cylinder 7 are combined with TixAly to form a cohesive state;

[0045] Step 4: Laying out raw materials

[0046] After the W, C, B powders and TixAly in the mixing drum 7 are mixed for 30-60 seconds, the first powder laying pipe vacuum valve 21 and the second powder laying pipe vacuum valve 4 are started to lay the mixture of the W, C, B powders and TixAly in the mixing drum 7 on the surface of the metal plate 1 through the first powder laying pipe 20 and the second powder laying pipe 2 respectively until the thickness reaches the design requirement;

[0047] Step 5: Vacuum sintering

[0048] The metal plate 1 is placed in a vacuum sintering furnace for high temperature sintering at a temperature of 800-1500° C. for 1-2 hours. After cooling, an ordered low-density high-porous film is obtained on the surface of the metal plate 1 .

[0049] In one implementation, in step 3, the order of inputting W, C, and B powders into the mixing drum 7 is to input W powder and C powder first, and pre-lay TixAly on the surface of the metal plate 1 as a base layer, and wait for the W powder and C powder to combine with TixAly to generate WC+W+C+TixAly, and then input B powder to generate B+TixAly. In step 4, this process makes the powder layer laid on the base layer on the surface of the metal plate 1 have a composition gradient of WC+W+C+TixAly and B+TixAly from bottom to top, respectively, and the thickness of the two powder layers is 200 microns; in the subsequent vacuum sintering process in step 5, the two powder layers undergo a chemical reaction to generate BC and WB, so that the final film layer composition gradient is WC+TixAly+W+C+BC+WB+B+TixAly, wherein B, BC, and WB are used as strengthening phases to enhance wear resistance, and the final film layer porosity is more than 90%.

[0050] In another embodiment, in the above technical scheme, the powder raw materials in the W raw material barrel 18, the C raw material barrel 14, and the B raw material barrel 10 are replaced with Mg, Al, and Zr respectively, and TixAly is pre-laid on the surface of the metal plate 1 as a base layer, and after the Mg, Al, and Zr powders are combined with TixAly, they are laid on the base layer on the surface of the metal plate 1 with a thickness of 200 microns. The laid powder layer has a composition gradient of Mg+TixAly+Al+Zr from bottom to top. After the vacuum sintering process, the final film layer composition gradient is Mg+TixAly+Al+ZrO, wherein ZrO is a flame retardant phase to enhance heat dissipation and flame retardancy, and the final film layer porosity is more than 90%.

Claims

1. A method for preparing an ordered low-density high-porosity film, characterized in that: The device used in the method comprises a W raw material barrel (18), a C raw material barrel (14), a B raw material barrel (10), and surrounding W raw material barrel heating sleeves (19), C raw material barrel heating sleeves (15), and B raw material barrel heating sleeves (9), as well as a W raw material channel (16), a C raw material channel (12), and a B raw material channel (8) for output. The above raw material channels are all provided with vacuum valves, namely, a W raw material channel vacuum valve (17), a C raw material channel vacuum valve (13), and a B raw material channel vacuum valve (11). The above raw material channels are all connected to a mixing barrel (7). Below the mixing barrel (7) is a blasting barrel (23), and a screen (5) is provided between the two. The mixing cylinder (7) and the blasting cylinder (23) are separated by a heating sleeve (6) around them. The two sides of the blasting cylinder (23) are connected to the Ti raw material cylinder (22) and the Al raw material cylinder (3) through pipelines. The two sides of the mixing cylinder (7) are respectively provided with a first powder laying pipe (20) and a second powder laying pipe (2). The first powder laying pipe (20) and the second powder laying pipe (2) are respectively installed in the middle of the first powder laying pipe (20) and the second powder laying pipe (2). The outlets of the first powder laying pipe (20) and the second powder laying pipe (2) are arranged above the metal plate (1) for laying powder on the surface of the metal plate (1); The steps of preparing an ordered low-density high-porosity film using the above device are as follows: Step 1: Raw material preparation The W, C and B powders are placed in the W raw material cylinder (18), the C raw material cylinder (14) and the B raw material cylinder (10) respectively, and the Ti and Al powders are placed in the Ti raw material cylinder (22) and the Al raw material cylinder (3) respectively; Start the W raw material barrel heating jacket (19), the C raw material barrel heating jacket (15), the B raw material barrel heating jacket (9), the left raw material barrel heating jacket (19), the middle raw material barrel heating jacket (15) and the right raw material barrel heating jacket (9), Preheating the W, C and B powders in the W raw material cylinder (18), the C raw material cylinder (14) and the B raw material cylinder (10) at a preheating temperature of 800-1400° C.; Step 2: Raw material blasting The heating jacket (6) is started, the temperature is heated to 1000-1100°C, and the temperature is kept for 30-60 minutes. Then, the Ti and Al powders in the Ti raw material tube (22) and the Al raw material tube (3) are input into the blasting tube (23). The power of the heating jacket (6) is increased, and the temperature in the blasting tube (23) is further increased by 200°C within 5-30 seconds, so that the Ti powder and the Al powder undergo an instantaneous thermal explosion reaction in the blasting tube (23). The thermal explosion reaction product TiXAlY passes through the screen (5) and enters the mixing tube (7) in an aerosol state. Step 3: Mixing of raw materials The vacuum valve (17) of the W raw material channel, the vacuum valve (13) of the C raw material channel, and the vacuum valve (11) of the B raw material channel are started to extract W, C, and B powders from the W raw material cylinder (18), the C raw material cylinder (14), and the B raw material cylinder (10), respectively, and then input into the mixing cylinder (7) through the W raw material channel (16), the C raw material channel (12), and the B raw material channel (8), respectively. When the W, C, and B powders enter the mixing cylinder (7), they are also in an aerosol state, and the W, C, and B powders in the mixing cylinder (7) are combined with TiXALY to form a cohesive state; Step 4: Laying out raw materials After the W, C, B powders and TixAly in the mixing drum (7) are kept mixed for 30-60 seconds, the first powder laying pipe vacuum valve (21) and the second powder laying pipe vacuum valve (4) are started to lay the mixture of the W, C, B powders and TixAly in the mixing drum (7) on the surface of the metal plate (1) through the first powder laying pipe (20) and the second powder laying pipe (2) respectively until the thickness reaches the design requirement; Step 5: Vacuum sintering The metal plate (1) is placed in a vacuum sintering furnace for high temperature sintering at a temperature of 800-1500° C. for 1-2 hours. After cooling, an ordered low-density high-porous film is obtained on the surface of the metal plate (1).

2. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: The sieve (5) is used to sieve out powder particles of -400 to -500 mesh.

3. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: The particle size of the W, C and B powders is -450 to -600 mesh.

4. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: The particle size of the Ti and Al powders is -400 to -500 meshes.

5. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: In step 3, the order of inputting W, C and B powders into the mixing drum (7) is to input W powder and C powder first, and to lay TixAly as a base layer on the surface of the metal plate (1) in advance, and to generate WC+W+C+TixAly after the W powder and C powder are combined with TixAly, and then input B powder to generate B+TixAly. In step 4, this process makes the powder layer laid on the base layer on the surface of the metal plate (1) have a composition gradient of WC+W+C+TixAly and B+TixAly from bottom to top. In the subsequent vacuum sintering process of step 5, the two powder layers undergo a chemical reaction to generate BC and WB, so that the final film layer composition gradient is WC+TixAly+W+C+BC+WB+B+TixAly, wherein B, BC and WB are used as strengthening phases to enhance wear resistance, and the final film layer porosity is more than 90%.

6. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: The thickness of the two powder layers is 200 microns.

7. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: The powder raw materials in the W raw material cylinder (18), the C raw material cylinder (14), and the B raw material cylinder (10) are replaced with Mg, Al, and Zr respectively, and TixAly is preliminarily laid on the surface of the metal plate (1) as a base layer. After the Mg, Al, and Zr powders are combined with TixAly, they are laid on the base layer on the surface of the metal plate (1) with a thickness of 200 microns. The laid powder layer has a composition gradient of Mg+TixAly+Al+Zr from bottom to top. After a vacuum sintering process, the final film layer has a composition gradient of Mg+TixAly+Al+ZrO, wherein ZrO is a flame retardant phase to enhance heat dissipation and flame retardancy. The final film layer has a porosity of more than 90%.

8. The method for preparing an ordered low-density high-porosity film according to claim 1, characterized in that: The diameter ratio of the raw material channel to the raw material cylinder is 1 / 20 to 1 / 30.

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