Novel high-temperature stealth material and preparation method thereof

Abstract

The invention discloses a novel high-temperature stealth material and a preparation method, and belongs to the technical field of electromagnetic stealth materials. The material is M12Al14O33, wherein M is Be, Mg, Ca, Sr or Ba; the preparation method comprises the following steps: taking Al (NO3) 3.9 H2O and M (NO3) 2.4 H2O as an Al source and an M source; the method comprises the following steps: respectively weighing an Al source and an M source according to an Al: M ratio of 14: 12, dissolving the Al source and the M source in deionized water to form a uniform solution, and dropwise adding the uniform solution into a proper amount of ammonia water to form gel; the dried gel is dried and ground, then high-temperature calcination is carried out, M12Al14O33 powder is obtained, and then ball milling, drying and sieving are carried out; the screened M12Al14O33 powder is prepared into the novel high-temperature stealth material by adopting a hot pressed sintering technology; the novel high-temperature stealth material has the advantages of being high in use temperature, good in chemical stability, large in wave absorbing bandwidth, small in application thickness and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electromagnetic stealth materials, and particularly relates to a novel high-temperature stealth material and a preparation method thereof. BACKGROUND

[0002] Since the stealth material has an absorption effect on the incident electromagnetic wave, the reflected electromagnetic wave energy is weakened, and then the stealth fighter and stealth warship and other weapon equipment can effectively avoid the tracking and positioning of the enemy radar detection system, realize the stealth effect, and thus improve the battlefield survival and penetration capability of the weapon equipment, so the stealth material has important significance in national defense construction.

[0003] According to different division bases, there are various types of stealth materials, for example, according to the working temperature, the stealth can be divided into low-temperature stealth materials (<400℃) and high-temperature stealth materials. Due to the extreme service environment, the performance requirements of the stealth material are more stringent. For example, when the stealth missile flies at the Mach number speed, due to the aerodynamic heating effect of the atmosphere, the surface temperature can reach thousands of degrees Celsius, and due to the strong ablation effect, the surface stealth material must have good high-temperature stability. In addition, the engine tail nozzle is also a strong radar scattering source, and at the same time, due to the heating effect of the tail nozzle flame, the high-temperature stealth performance of the thermal end stealth component is also in urgent need. In the face of extreme service conditions, the traditional stealth material has been difficult to work, and therefore it is urgent to develop a new type of high-temperature stealth material with high stealth performance.

[0004] Compared with metal, C-based, MAX phase-based and other stealth materials, oxide ceramic materials have strong covalent bonds as the main type of chemical bond, which is a strong bond. Oxide ceramic materials usually have high strength, acid, alkali salt corrosion resistance, high hardness, good wear resistance and excellent high-temperature stability, and are important objects for stealth material research under extreme service conditions. However, there are few researches and reports on high-performance, novel oxide high-temperature stealth materials at present, and therefore it is urgent to develop a new type of oxide stealth material. SUMMARY

[0005] In view of the problems in the prior art, a first purpose of the present application is to obtain a novel high-temperature stealth material, which has excellent stealth performance, thin thickness when applied, and good high-temperature stability performance; and a second purpose is to provide a preparation method of the novel high-temperature stealth material.

[0006] The first purpose of the present application is achieved in that the novel high-temperature stealth material is M 12 Al 14 O 33 , wherein M is any one or any combination of Be, Mg, Ca, Sr or Ba.

[0007] The second object of the present application is achieved in that the preparation method of the new high-temperature stealth material comprises the following steps:

[0008] (1) taking Al(NO3)3·9H2O and M(NO3)2·4H2O as raw materials and ammonia water as solvent; 0.07 mol of Al(NO3)3·9H2O and 0.06 mol of M(NO3)2·4H2O are weighed according to the molar ratio of Al:M=14:12 and dissolved in 200 mL of deionized water to form a uniform solution; the uniform solution is added dropwise into 300 mL of 28% ammonia water, stirred uniformly to form M 12 Al 14 O 33 colloid; the M 12 Al 14 O 33 colloid is separated from the ammonia water by suction filtration, and repeatedly washed and treated by suction filtration with deionized water to form M 12 Al 14 O 33 gel;

[0009] (2) the M 12 Al 14 O 33 gel obtained in step (1) is dried and ground, and then calcined at 600-1600°C for 1-20 h; the M 12 Al 14 O 33 powder obtained by calcination is subjected to ball milling treatment, and the M 12 Al 14 O 33 slurry after ball milling is dried and treated and then sieved through a 200-mesh sieve;

[0010] (3) the M 12 Al 14 O 33 powder sieved in step (2) is hot-pressed sintered at 1000-1600°C and 10-50 MPa for 1-10 h to obtain a M 12 Al 14 O 33 high-temperature stealth material.

[0011] Compared with the prior art, the new high-temperature stealth material has the following beneficial effects:

[0012] 1) simple synthesis process and high product purity;

[0013] 2) stable high-temperature chemical properties, capable of safe and stable service at high temperature (1200-1800°C) for a long time;

[0014] 3) good stealth performance, with advantages such as thin thickness, strong absorption peak and large effective bandwidth. DETAILED DESCRIPTION

[0015] The application will be further described in connection with the following specific examples, but not in any way limited to them, any transformation or substitution based on the teaching of the application shall fall within the protection scope of the application.

[0016] The new high-temperature stealth material according to the application is M 12 Al 14 O 33 , wherein M is any or any combination of Be, Mg, Ca, Sr or Ba.

[0017] The preparation method of the new high-temperature stealth material according to the application comprises the following steps:

[0018] (1) taking Al(NO3)3·9H2O and M(NO3)2·4H2O as raw materials and ammonia water as solvent; 0.07 mol of Al(NO3)3·9H2O and 0.06 mol of M(NO3)2·4H2O are weighed according to the molar ratio of Al:M=14:12 and dissolved in 200 mL of deionized water to form a uniform solution by stirring; the uniform solution is added dropwise into 300 mL of 28% ammonia water, stirred uniformly to form M 12 Al 14 O 33 colloid; the M 12 Al 14 O 33 colloid is separated from the ammonia water by suction filtration, and repeatedly washed and treated by suction filtration with deionized water to form M 12 Al 14 O 33 gel;

[0019] (2) the M 12 Al 14 O 33 gel obtained in step (1) is dried and ground, and then calcined at 600-1600℃ for 1-20 h; the M 12 Al 14 O 33 powder obtained by calcination is subjected to ball milling treatment, and the M 12 Al 14 O 33 slurry after drying treatment is sieved through a 200-mesh screen;

[0020] (3) the M 12 Al 14 O 33 powder sieved in step (2) is hot-pressed sintered at 1000-1600℃ and 10-50 MPa for 1-10 h to obtain M 12 Al 14 O33 High-temperature stealth material.

[0021] Further, in step (1), the deionized water is repeatedly washed for 3 times, each time using 300 mL of deionized water for washing.

[0022] Further, in step (1), the uniform solution is added to 300 mL of 28% mass fraction ammonia water at a rate of 30 drops / min.

[0023] Further, in step (2), the M 12 Al 14 O 33 gel is dried in a blast drying oven at 150°C for 10 h. 12 Al 14 O 33 The slurry is dried at 50-200°C for 3-10 h.

[0024] Further, in step (2), the M 12 Al 14 O 33 The gel is dried in a blast drying oven at 150°C for 10 h.

[0025] Further, in step (2), the M 12 Al 14 O 33 The slurry is dried at 150°C for 5 h.

[0026] Further, in step (2), the M 12 Al 14 O 33 After drying and grinding, the gel is calcined at 1200°C for 10 h.

[0027] Further, in step (2), when the ball milling treatment is performed, anhydrous ethanol is used as the ball milling solvent, the mass ratio of ball to material is 10:1, the ball milling rotation speed is 600 rpm, and the ball milling time is 10 h.

[0028] Further, in step (3), the M 12 Al 14 O 33 The powder is hot-pressed and sintered at 1200°C and 50 MPa for 2 h.

[0029] Example 1: Preparation of a new high-temperature stealth material Be 12 Al 14 O 33 The specific steps are as follows:

[0030] (1) Take Al (NO3) 3*9H2O and Be (NO3) 2*4H2O as raw materials, take 0.07 mol Al (NO3) 3*9H2O and 0.06 mol Be (NO3) 2*4H2O according to the molar ratio of Al:Be=14:12, and dissolve them in 200 mL of deionized water in sequence, and form a uniform solution under the action of magnetic stirring; drop the uniform solution into 300 mL of 28% ammonia water at a speed of 30 drops per minute, and form a uniform Be 12 Al 14 O 33 colloid; separate the Be 12 Al 14 O 33 colloid from ammonia water by suction filtration, and wash and suction filter the Be 12 Al 14 O 33 colloid for 3 times with deionized water to form Be 12 Al 14 O 33 gel, and the deionized water used for each washing is 300 mL;

[0031] (2) dry the Be 12 Al 14 O 33 gel obtained in step (1) in a blast drying oven at 150°C for 10 h, then grind and treat, and then place it in a muffle furnace and calcine it at 1200°C for 10 h; ball mill the Be 12 Al 14 O 33 powder obtained by calcination, and the ball milling solvent is anhydrous ethanol, the mass ratio of ball to material is 10:1, the ball milling speed is 600 rpm, and the ball milling time is 10 h; dry the Be 12 Al 14 O 33 slurry at 150°C for 5 h, and then pass it through a 200-mesh sieve;

[0032] (3) high-temperature hot-press sinter the Be 12 Al 14 O 33 powder sieved in step (2) at 1200°C for 2 h, and the sintering pressure is 50 MPa, to obtain a high-temperature stealth material Be 12 Al 14 O 33 .

[0033] Example 2: Preparation of a new high-temperature stealth material Mg 12 Al 14 O 33 , and the specific steps are as follows:

[0034] (1) Take Al (NO3) 3.9H2O and Mg (NO3) 2.4H2O as raw materials, take 0.07 mol Al (NO3) 3.9H2O and 0.06 mol Mg (NO3) 2.4H2O according to the molar ratio of Al:Mg=14:12, and dissolve them in 200 mL of deionized water in sequence, and form a uniform solution under the action of magnetic stirring; drop the uniform solution into 300 mL of 28% ammonia water at a speed of 30 drops per minute, and form a uniform Mg 12 Al 14 O 33 colloid under the action of magnetic stirring; separate the Mg 12 Al 14 O 33 colloid from the ammonia water by suction filtration, and wash and suction filter the Mg 12 Al 14 O 33 colloid with deionized water for 3 times to form Mg 12 Al 14 O 33 gel, and the amount of deionized water used for each washing is 300 mL;

[0035] (2) Dry the Mg 12 Al 14 O 33 gel obtained in step (1) in a blast drying oven at 150°C for 10 h, then grind and treat, and then place it in a muffle furnace and calcine it at 1200°C for 10 h; ball mill the Mg 12 Al 14 O 33 powder obtained by calcination, the ball milling solvent is anhydrous ethanol, the mass ratio of ball to material is 10:1, the ball milling speed is 600 rpm, and the ball milling time is 10 h; dry the Mg 12 Al 14 O 33 slurry at 150°C for 5 h, and then pass it through a 200-mesh sieve;

[0036] (3) High-temperature hot-press sinter the Mg 12 Al 14 O 33 powder sieved in step (2) at 1200°C for 2 h, and the sintering pressure is 50 MPa, to obtain a high-temperature stealth material Mg 12 Al 14 O 33 .

[0037] Example 3: Preparation of a new high-temperature stealth material Ca 12 Al 14 O 33 , and the specific steps are as follows:

[0038] (1) Take Al (NO3) 3.9H2O and Ca (NO3) 2.4H2O as raw materials, 0.07 mol Al (NO3) 3.9H2O and 0.06 mol Ca (NO3) 2.4H2O are weighed according to the molar ratio of Al: Ca = 14: 12, and then dissolved in 200 mL of deionized water, and a uniform solution is formed under the action of magnetic stirring; The uniform solution is added dropwise to 300 mL of 28% ammonia water at a speed of 30 drops per minute, and a uniform Ca 12 Al 14 O 33 Colloid; the Ca 12 Al 14 O 33 Colloid is separated from ammonia water by suction filtration, and the Ca 12 Al 14 O 33 Colloid is washed and suction filtered for 3 times by using deionized water, and the Ca 12 Al 14 O 33 Gel is formed, and the amount of deionized water used for each washing is 300 mL;

[0039] (2) The Ca 12 Al 14 O 33 Gel obtained in step (1) is dried in a blast drying oven at 150 ℃ for 10 h, then ground and treated, and then placed in a muffle furnace at 1200 ℃ for calcination for 10 h; The Ca 12 Al 14 O 33 Powder obtained by calcination is subjected to ball milling treatment, the ball milling solvent is anhydrous ethanol, the mass ratio of ball to material is 10:1, the ball milling speed is 600 rpm, and the ball milling time is 10 h; The Ca 12 Al 14 O 33 Slurry after ball milling is dried at 150 ℃ for 5 h, and then sieved through a 200 mesh sieve;

[0040] (3) The Ca 12 Al 14 O 33 Powder sieved in step (2) is high-temperature hot-pressed sintered at 1200 ℃ for 2 h, and the sintering pressure is 50 MPa, to obtain a high-temperature stealth material Ca 12 Al 14 O 33 .

[0041] Example 4: Preparation of a new type of high-temperature stealth material Sr 12 Al 14 O 33 , the specific steps are as follows:

[0042] (1) Take Al (NO3) 3.9H2O and Sr (NO3) 2.4H2O as raw materials, weigh 0.07 mol Al (NO3) 3.9H2O and 0.06 mol Sr (NO3) 2.4H2O according to the molar ratio of Al:Sr=14:12, and dissolve them in 200 mL deionized water successively, to form a uniform solution under the action of magnetic stirring; drop the uniform solution into 300 mL 28% ammonia water at a speed of 30 drops per minute, and form a uniform Sr 12 Al 14 O 33 colloid under the action of magnetic stirring; separate the Sr 12 Al 14 O 33 colloid from ammonia water by suction filtration, and wash and suction filter the Sr 12 Al 14 O 33 colloid with deionized water for 3 times to form Sr 12 Al 14 O 33 gel, and the deionized water used for each washing is 300 mL;

[0043] (2) Dry the Sr 12 Al 14 O 33 gel obtained in step (1) in a blast drying oven at 150°C for 10 h, then grind and treat, and then place it in a muffle furnace for calcination at 1200°C for 10 h; ball mill the Sr 12 Al 14 O 33 powder obtained by calcination, and the ball milling solvent is anhydrous ethanol, the mass ratio of ball to material is 10:1, the ball milling speed is 600 rpm, and the ball milling time is 10 h; dry the Sr 12 Al 14 O 33 slurry at 150°C for 5 h, and then pass it through a 200-mesh sieve;

[0044] (3) High-temperature hot-press sinter the Sr 12 Al 14 O 33 powder sieved in step (2) at 1200°C for 2 h, and the sintering pressure is 50 MPa, to obtain a high-temperature stealth material Sr 12 Al 14 O 33 .

[0045] Example 5 New high-temperature stealth material Ba 12 Al 14 O 33 , and the specific steps are as follows:

[0046] (1) Take Al (NO3) 3·9H2O and Ba (NO3) 2·4H2O as raw materials, 0.07 mol Al (NO3) 3·9H2O and 0.06 mol Ba (NO3) 2·4H2O are weighed according to the molar ratio of Al: Ba = 14: 12, and then dissolved in 200 mL of deionized water, and a uniform solution is formed under the action of magnetic stirring; The uniform solution is added dropwise to 300 mL of 28% ammonia water at a speed of 30 drops per minute, and a uniform Ba 12 Al 14 O 33 colloid is formed under the action of magnetic stirring; The Ba 12 Al 14 O 33 colloid is separated from ammonia water by suction filtration, and deionized water is used to wash and suction filter the Ba 12 Al 14 O 33 colloid for 3 times, forming Ba 12 Al 14 O 33 gel, and the amount of deionized water used for each washing is 300 mL;

[0047] (2) The Ba 12 Al 14 O 33 gel obtained in step (1) is dried in a blast drying oven at 150°C for 10h, then ground and placed in a muffle furnace at 1200°C for calcination for 10h; The Ba 12 Al 14 O 33 powder obtained by calcination is subjected to ball milling treatment, the ball milling solvent is anhydrous ethanol, the mass ratio of ball to material is 10:1, the ball milling speed is 600 rpm, and the ball milling time is 10h; The Ba 12 Al 14 O 33 slurry after ball milling is dried at 150°C for 5h, and then sieved through a 200 mesh sieve;

[0048] (3) The Ba 12 Al 14 O 33 powder sieved in step (2) is high-temperature hot-pressed sintered at 1200°C for 2h, and the sintering pressure is 50MPa, to obtain a high-temperature stealth material Ba 12 Al 14 O 33 .

[0049] Test Example The new high-temperature stealth materials obtained in Examples 1-5 are tested for their reflection loss values and frequencies at 1000°C with a thickness of 1.1-1.5mm.

[0050] Table 1 is the Be12 Al 14 O 33 Corresponding relationship between reflection loss value and frequency when the thickness of the stealth material is 1.3mm

[0051] Table 2 is Mg in example 2 12 Al 14 O 33 Corresponding relationship between reflection loss value and frequency when the thickness of the stealth material is 1.5mm

[0052] Table 3 is Ca in example 3 12 Al 14 O 33 Corresponding relationship between reflection loss value and frequency when the thickness of the stealth material is 1.1mm

[0053] Table 4 is Sr in example 4 12 Al 14 O 33 Corresponding relationship between reflection loss value and frequency when the thickness of the stealth material is 1.2mm

[0054] Table 5 is Ba in example 5 12 Al 14 O 33 Corresponding relationship between reflection loss value and frequency when the thickness of the stealth material is 1.4mm

[0055] From the above test examples, it can be seen that the novel high-temperature stealth material overcomes the defects of the prior art stealth material and has an ideal application prospect.

Claims

1. A novel high-temperature stealth material, characterized in that, The novel high-temperature stealth material is M. 12 Al 14 O 33 , where M is any or any combination of Be, Mg, Ca, Sr or Ba.

2. A method for preparing the novel high-temperature stealth material according to claim 1, characterized in that, Includes the following steps: (1) Using Al(NO3)3·9H2O and M(NO3)2·4H2O as raw materials and ammonia water as solvent; weigh 0.07 mol Al(NO3)3·9H2O and 0.06 mol M(NO3)2·4H2O according to the molar ratio Al:M=14:12 and dissolve them in 200 mL of deionized water and stir to form a homogeneous solution; add the homogeneous solution dropwise to 300 mL of 28% ammonia water and stir until homogeneous to form M 12 Al 14 O 33 Colloid; M by vacuum filtration 12 Al 14 O 33 The colloid was separated from the ammonia water and repeatedly washed and filtered with deionized water to form M. 12 Al 14 O 33 gel; (2) Take the M obtained in step (1) 12 Al 14 O 33 After drying and grinding, the gel is calcined at 600-1600℃ for 1-20 hours. The resulting M is then... 12 Al 14 O 33 The powder is ball-milled, and the resulting M 12 Al 14 O 33 The slurry is dried and then passed through a 200-mesh sieve. (3) The M obtained by sieving in step (2) 12 Al 14 O 33 The powder was hot-pressed and sintered at 1000~1600℃ and 10~50 MPa for 1~10h to obtain M. 12 Al 14 O 33 High-temperature stealth materials.

3. The preparation method according to claim 2, characterized in that, In step (1), the washing is repeated 3 times with deionized water, each time using 300 mL of deionized water.

4. The preparation method according to claim 2, characterized in that, In step (1), the homogeneous solution is added dropwise at 30 drops / min to 300 mL of ammonia water with a mass fraction of 28%.

5. The preparation method according to claim 2, characterized in that, In step (2), M 12 Al 14 O 33 Gel, M 12 Al 14 O 33 The slurry is dried at 50~200℃ for 3~10 hours.

6. The preparation method according to claim 2 or 5, characterized in that, In step (2), M 12 Al 14 O 33 The gel was dried in a forced-air drying oven at 150°C for 10 hours.

7. The preparation method according to claim 2 or 5, characterized in that, In step (2), M 12 Al 14 O 33 The slurry was dried at 150℃ for 5 hours.

8. The preparation method according to claim 2, characterized in that, In step (2), M 12 Al 14 O 33 The gel was dried, ground, and then calcined at 1200℃ for 10 hours.

9. The preparation method according to claim 2, characterized in that, In step (2), anhydrous ethanol is used as the ball milling solvent, the ball-to-material mass ratio is 10:1, the ball milling speed is 600 rpm, and the ball milling time is 10 h.

10. The preparation method according to claim 2, characterized in that, In step (3), M 12 Al 14 O 33 The powder was hot-pressed and sintered at 1200℃ and 50MPa for 2 hours.

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