Method for preparing high-temperature resistant broadband wave-absorbing inorganic polymer-based composite material components by 3D printing

Abstract

The present invention discloses a method for preparing high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material components by 3D printing. The method is to solve the problem of low heat resistance temperature of existing aluminum wave-absorbing honeycomb materials. The method for preparing inorganic polymer-based composite material components by 3D printing includes the following steps: 1. adding aluminum hydroxide powder to a phosphoric acid activator solution, heating the solution for reaction, and then adding a ceramic powder containing aluminum to obtain an inorganic polymer slurry; 2. adding wave-absorbing particles to the inorganic polymer slurry; 3. adding a rheology control agent to the inorganic polymer-based composite material slurry; 4. performing additive manufacturing on the modified inorganic polymer-based composite material slurry using an extrusion-type 3D printer; 5. performing a curing treatment; 6. performing a high-temperature treatment on the composite material blank. The broadband wave-absorbing inorganic polymer-based composite material component prepared by 3D printing of the present invention is resistant to high temperatures and exhibits broadband wave-absorbing characteristics, with a reflection loss of ≤-10dB in the frequency range of 2 to 18 GHz.

Description

Technical Field

[0001] The invention relates to a method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component. Background Art

[0002] With the rapid development of today's electronics industry, electromagnetic radiation has become a new form of environmental pollution. Absorbing materials also play an important role in environmental protection. Therefore, conducting research on absorbing materials has far-reaching significance both for military and civilian use.

[0003] Aircraft stealth is crucial to victory in modern warfare. However, as aircraft Mach numbers increase, the requirements for heat resistance and radar-absorbing stealth in areas such as the nose become increasingly stringent. Traditional stealth coatings, primarily composed of radar-absorbing particles and an epoxy resin binder, have poor heat resistance. Furthermore, aluminum radar-absorbing honeycombs have a maximum heat resistance of no more than 300°C. Therefore, the development of new heat-resistant, radar-absorbing material systems is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of low heat resistance temperature of existing aluminum absorbing honeycomb materials and to provide a method for preparing high-temperature resistant broadband absorbing inorganic polymer-based composite material components by 3D printing.

[0005] The method of preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing of the present invention is implemented by the following steps:

[0006] 1. Preparation of inorganic polymer slurry:

[0007] Aluminum hydroxide powder is added to a phosphoric acid activator solution, and the molar ratio of phosphorus in the phosphoric acid to aluminum in the aluminum hydroxide is adjusted to P / Al = 2 to 4. The mixture is reacted at a temperature of 50 to 80°C to obtain a solution containing aluminum dihydrogen phosphate. A ceramic powder containing aluminum is then added to obtain an inorganic polymer slurry.

[0008] 2. Preparation of Inorganic Polymer-based Composite Material Slurry:

[0009] Adding wave-absorbing particles to the inorganic polymer slurry and stirring uniformly with a high-speed mechanical device to obtain an inorganic polymer-based composite material slurry;

[0010] 3. Rheological control of inorganic polymer-based composite material slurry:

[0011] adding a rheology control agent to the inorganic polymer-based composite material slurry to obtain a modified inorganic polymer-based composite material slurry;

[0012] 4. Additive manufacturing of inorganic polymer-based composites:

[0013] The modified inorganic polymer-based composite material slurry is additively manufactured using an extrusion-type 3D printer to obtain an inorganic polymer-based component, wherein the inorganic polymer-based component is a (stacked) mesh array structure;

[0014] 5. Curing of additively manufactured inorganic polymer-based composites:

[0015] The inorganic polymer-based component is placed in an oven for curing, and the curing temperature is controlled to be 100-300° C. to obtain a composite material green body;

[0016] 6. Post-processing of additively manufactured inorganic polymer-based composites:

[0017] The composite material blank is subjected to high temperature treatment at a temperature of 400 to 600° C. and kept at this temperature for 1 to 2 hours to obtain a high temperature resistant broadband wave absorbing inorganic polymer based composite material component;

[0018] The wave-absorbing particles described in step 2 are one or a mixture of graphene, carbon nanotubes, graphite powder, carbon black, modified silicon carbide, ferrite and strontium ferrite.

[0019] The material of the high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component prepared by 3D printing of the present invention is a high-temperature resistant inorganic polymer, and the inorganic polymer itself is a wave-transparent matrix, which can achieve good impedance matching, thereby facilitating the entry of electromagnetic waves into the material. The wave-absorbing particles inside the inorganic polymer absorb electromagnetic waves through electric / magnetic loss, and through periodic structures such as honeycomb meshes, the repeated oscillation and consumption of electromagnetic waves in the structure can be achieved, thereby achieving broadband wave absorption.

[0020] The apparent density of the high-temperature resistant broadband wave-absorbing inorganic polymer-based composite material component prepared by the present invention is 1.0-2.0 g / cm 3 , compressive strength greater than 50MPa, and reflection loss ≤-10dB in the frequency range of 2 to 18GHz.

[0021] The present invention proposes a method for preparing an inorganic polymer-based composite material that can be prepared at low temperature and used at high temperature. The method can ensure that the composite material can be prepared at a relatively low temperature, and at the same time can be resistant to high temperatures and exhibit broadband wave-absorbing properties. The heat-resistant temperature reaches above 1500°C, which can meet the urgent demand for heat-resistant wave-absorbing properties on the surface of aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a photo of the high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material prepared in the examples;

[0023] Figure 2 This is a test graph of reflectivity loss at different frequencies for the high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material prepared in the embodiment;

[0024] Figure 3 This is a photo of a honeycomb structured inorganic polymer-based composite material component obtained by additive manufacturing in the example;

[0025] Figure 4 This is a test chart of reflectivity loss at different frequencies of the honeycomb structure inorganic polymer-based composite material component obtained by additive manufacturing in the example. DETAILED DESCRIPTION

[0026] Specific embodiment 1: The method of preparing a high-temperature resistant broadband wave-absorbing inorganic polymer-based composite material component by 3D printing in this embodiment is implemented according to the following steps:

[0027] 1. Preparation of inorganic polymer slurry:

[0028] Aluminum hydroxide powder is added to a phosphoric acid activator solution, and the molar ratio of phosphorus in the phosphoric acid to aluminum in the aluminum hydroxide is adjusted to P / Al = 2 to 4. The mixture is reacted at a temperature of 50 to 80°C to obtain a solution containing aluminum dihydrogen phosphate. A ceramic powder containing aluminum is then added to obtain an inorganic polymer slurry.

[0029] 2. Preparation of Inorganic Polymer-based Composite Material Slurry:

[0030] Adding wave-absorbing particles to the inorganic polymer slurry and stirring uniformly with a high-speed mechanical device to obtain an inorganic polymer-based composite material slurry;

[0031] 3. Rheological control of inorganic polymer-based composite material slurry:

[0032] adding a rheology control agent to the inorganic polymer-based composite material slurry to obtain a modified inorganic polymer-based composite material slurry;

[0033] 4. Additive manufacturing of inorganic polymer-based composites:

[0034] The modified inorganic polymer-based composite material slurry is additively manufactured using an extrusion-type 3D printer to obtain an inorganic polymer-based component, wherein the inorganic polymer-based component is a (stacked) mesh array structure;

[0035] 5. Curing of additively manufactured inorganic polymer-based composites:

[0036] The inorganic polymer-based component is placed in an oven for curing, and the curing temperature is controlled to be 100-300° C. to obtain a composite material green body;

[0037] 6. Post-processing of additively manufactured inorganic polymer-based composites:

[0038] The composite material blank is subjected to high temperature treatment at a temperature of 400 to 600° C. and kept at this temperature for 1 to 2 hours to obtain a high temperature resistant broadband wave absorbing inorganic polymer based composite material component;

[0039] The wave-absorbing particles described in step 2 are one or a mixture of graphene, carbon nanotubes, graphite powder, carbon black, modified silicon carbide, ferrite and strontium ferrite.

[0040] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the concentration of the phosphoric acid activator solution in step 1 is 30-70 wt%.

[0041] Specific embodiment three: This embodiment differs from specific embodiment one or two in that the ceramic powder containing aluminum element in step one is a mixture of one or more of alumina, boehmite, kaolin and metakaolin.

[0042] Specific embodiment 4: The difference between this embodiment and any one of specific embodiments 1 to 3 is that the P / Al molar ratio in the inorganic polymer slurry in step 1 is 1:(0.8-1.2).

[0043] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that step 2 is high-speed mechanical stirring at a speed of 400 to 1500 rpm for 10 to 60 minutes.

[0044] Specific embodiment 6: The difference between this embodiment and specific embodiments 1 to 5 is that the amount of the added absorbing particles in step 2 accounts for 18 wt% to 24 wt% of the inorganic polymer slurry.

[0045] This embodiment requires the regulation of the amount of absorbing particles added. For example, if the content of absorbing particles is too high, the impedance matching will deteriorate, and the rheological viscosity and yield stress will be affected, resulting in the collapse of the printed component and low printing deformation accuracy.

[0046] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that the rheology control agent described in step three is gelatin, gum arabic, gum tragacanth, xanthan gum, sodium alginate, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylic acid, polyethylene oxide, polyvinyl alcohol or polyvinyl pyrrolidone.

[0047] Specific embodiment eight: The difference between this embodiment and specific embodiments one to seven is that the viscosity of the inorganic polymer-based composite material slurry after step three modification is 10 3 ~10 5 Pa·s, yield stress is 2000~10000Pa.

[0048] The viscosity of the slurry in this embodiment is measured using a rheometer.

[0049] In this embodiment, a rheology modifier is added to the inorganic polymer-based composite material slurry in an amount of 0.01wt% to 0.05wt% of the inorganic polymer-based composite material slurry. The rheology modifier is used to control the viscosity and yield stress of the inorganic polymer-based composite material slurry. Excessive viscosity prevents extrusion during 3D printing, while low viscosity makes the slurry difficult to form by collapsing. Viscosity and yield stress directly affect the structural stability and formability of printed products.

[0050] The optimized viscosity of the modified inorganic polymer-based composite material slurry in this embodiment is 10 4 Pa·s, and the optimized yield stress is 3000Pa~5000Pa.

[0051] Specific embodiment 9: The difference between this embodiment and any one of specific embodiments 1 to 8 is that in step 4, the inorganic polymer-based component is a mesh array structure, and the mesh is in the shape of a honeycomb hole, a circular hole or a rectangular hole.

[0052] The present embodiment preferably uses a honeycomb hole array structure.

[0053] Specific embodiment ten: This embodiment differs from specific embodiments one to nine in that the curing treatment is performed at a temperature of 250 to 300° C. for 1.5 to 2.5 hours in step five.

[0054] Specific embodiment 11: The difference between this embodiment and specific embodiments 1 to 10 is that in step 6, the composite material blank is subjected to high-temperature treatment at a temperature of 400° C. and kept warm for 1 hour.

[0055] Example: The preparation method of the high-temperature resistant broadband wave-absorbing inorganic polymer-based composite material component of this embodiment is implemented according to the following steps:

[0056] 1. Preparation of inorganic polymer slurry:

[0057] Aluminum hydroxide powder was added to a 60 wt% phosphoric acid activator solution, with the P / Al molar ratio adjusted to 3, and the mixture was reacted at 75°C for 8 hours to obtain a clear and transparent solution containing aluminum dihydrogen phosphate. Alumina ceramic powder was then added, with the P / Al molar ratio in the final slurry adjusted to 1, to obtain an inorganic polymer slurry.

[0058] 2. Preparation of Inorganic Polymer-based Composite Material Slurry:

[0059] Adding graphite absorbing particles to the inorganic polymer slurry in an amount of 20 wt % of the inorganic polymer slurry, and mechanically stirring the mixture at a high speed of 800 rpm for 30 minutes to obtain an inorganic polymer-based composite material slurry;

[0060] 3. Rheological control of inorganic polymer-based composite material slurry:

[0061] The rheology control agent Triton-100 was added to the inorganic polymer-based composite material slurry, and the amount of Triton added was 0.01wt% of the inorganic polymer-based composite material slurry to obtain a modified inorganic polymer-based composite material slurry. The viscosity of the slurry was 10 4 Pa·s, a yield stress of 4000 Pa and exhibits shear-thinning properties;

[0062] 4. Additive manufacturing of inorganic polymer-based composites:

[0063] The modified inorganic polymer-based composite material slurry is additively manufactured using an extrusion 3D printer to obtain an inorganic polymer-based component. The inorganic polymer-based component is a honeycomb mesh array structure (such as Figure 3 shown);

[0064] 5. Curing of additively manufactured inorganic polymer-based composites:

[0065] The inorganic polymer-based component was placed in an oven for curing treatment, with a heating rate of 1°C / min, and the curing temperature was raised to 300°C and kept at this temperature for 2 hours to avoid warping of the sample, thereby obtaining a composite material green body;

[0066] 6. Post-processing of additively manufactured inorganic polymer-based composites:

[0067] The composite material blank is subjected to high temperature treatment at a temperature of 400° C. and kept warm for 1 hour to obtain a high temperature resistant broadband wave absorbing inorganic polymer based composite material component.

[0068] Depend on Figure 2 The reflectivity loss test graph shows that the inorganic polymer composite powder prepared by the present invention has a narrow absorption frequency. Figure 4 It can be seen from the reflectivity loss test chart that the inorganic polymer-based composite material components obtained by 3D printing have broadband wave absorption performance.

Claims

1. A method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing, characterized in that The method for preparing a high-temperature resistant broadband wave-absorbing inorganic polymer-based composite material component is implemented by the following steps:

1. Preparation of inorganic polymer slurry: Aluminum hydroxide powder is added to a phosphoric acid activator solution, and the molar ratio of phosphorus in the phosphoric acid to aluminum in the aluminum hydroxide is adjusted to P / Al = 2 to 4. The mixture is reacted at a temperature of 50 to 80°C to obtain a solution containing aluminum dihydrogen phosphate. A ceramic powder containing aluminum is then added to obtain an inorganic polymer slurry.

2. Preparation of Inorganic Polymer-based Composite Material Slurry: Adding wave-absorbing particles to the inorganic polymer slurry and stirring uniformly with a high-speed mechanical device to obtain an inorganic polymer-based composite material slurry; 3. Rheological control of inorganic polymer-based composite material slurry: adding a rheology control agent to the inorganic polymer-based composite material slurry to obtain a modified inorganic polymer-based composite material slurry; 4. Additive manufacturing of inorganic polymer-based composites: The modified inorganic polymer-based composite material slurry is additively manufactured using an extrusion-type 3D printer to obtain an inorganic polymer-based component having a mesh array structure; 5. Curing of additively manufactured inorganic polymer-based composites: The inorganic polymer-based component is placed in an oven for curing, and the curing temperature is controlled to be 100-300° C. to obtain a composite material green body; 6. Post-processing of additively manufactured inorganic polymer-based composites: The composite material blank is subjected to high temperature treatment at a temperature of 400 to 600° C. and kept at this temperature for 1 to 2 hours to obtain a high temperature resistant broadband wave absorbing inorganic polymer based composite material component; The wave-absorbing particles described in step 2 are one or a mixture of graphene, carbon nanotubes, graphite powder, carbon black, modified silicon carbide, ferrite and strontium ferrite.

2. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that The concentration of the phosphoric acid activator solution in step 1 is 30-70 wt %.

3. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that The ceramic powder containing aluminum in step 1 is a mixture of one or more of alumina, boehmite, kaolin and metakaolin.

4. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that Step 1: The P / Al molar ratio in the inorganic polymer slurry is 1: (0.8-1.2).

5. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that In step 2, the amount of the added wave-absorbing particles accounts for 18 wt% to 24 wt% of the inorganic polymer slurry.

6. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that The rheology control agent in step 3 is gelatin, gum arabic, gum tragacanth, xanthan gum, sodium alginate, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylic acid, polyethylene oxide, polyvinyl alcohol or polyvinyl pyrrolidone.

7. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that The viscosity of the modified inorganic polymer-based composite material slurry is 10 3 ~10 5 Pa·s, yield stress is 2000~10000Pa.

8. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that Step 4: The inorganic polymer-based component is a mesh array structure, and the mesh is in the shape of a honeycomb hole, a circular hole or a rectangular hole.

9. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that In step five, the curing treatment is carried out at a temperature of 250 to 300° C. for 1.5 to 2.5 hours.

10. The method for preparing a high-temperature resistant, broadband wave-absorbing inorganic polymer-based composite material component by 3D printing according to claim 1, characterized in that In step six, the composite material body is subjected to high temperature treatment at a temperature of 400° C. and kept at this temperature for 1 hour.

Images