In-situ composite preparation method of calcium phosphate / boron nitride high-temperature wave-absorbing material and application thereof

Abstract

The application relates to an in-situ composite preparation method of a calcium phosphate / boron nitride high-temperature wave-absorbing material and application thereof, and belongs to the technical field of wave-absorbing materials. The method solves the problem that traditional insulator materials boron nitride have no electromagnetic wave absorption capacity. The method comprises the following steps: preparing Ca3(PO4)2 ion oligomers; preparing Ca3(PO4)2 ion oligomer gel; preparing a transparent hot solution of melamine diboric acid, then mixing the transparent hot solution of melamine diboric acid with the Ca3(PO4)2 ion oligomer gel, and then cooling, centrifuging, drying and sintering, so that the preparation is completed. The calcium phosphate / boron nitride high-temperature wave-absorbing material is prepared by adopting the in-situ composite mode, the process is simple, the cost is low, the process is green and pollution-free; the wave-transparent boron nitride material is converted into a wave-absorbing material through the simple composite of inorganic non-metallic substances, the balanced magnetic property and polarization effect of the material are matched with each other, high-strength and wide-band electromagnetic wave absorption performance is finally realized, and meanwhile, the lightweight and high-temperature-resistant characteristics of boron nitride are maintained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wave-absorbing materials, and particularly relates to an in-situ composite preparation method of calcium phosphate / boron nitride high-temperature wave-absorbing material and application thereof. BACKGROUND

[0002] In the field of aerospace technology and military technology, the rapid development of new aircraft and missile weapons puts forward higher requirements for the flight Mach number, which requires that the stealth coating of the aircraft and missile shell can withstand the harsh environment of high aerodynamic load and high aerodynamic heat. In order to meet the requirements of bearing and heat insulation, the aircraft shell plays the role of bearing aerodynamic load, resisting ablation and preventing heat, the inner lining plays the role of heat insulation, and both of them need to meet the requirements of shielding electromagnetic waves and being light and small in density.

[0003] In most cases, most metals, ferrites and carbon materials are often candidates for wave-absorbing materials. Metals and ferrites have both dielectric and magnetic double losses, and can exhibit excellent wave-absorbing performance. However, metals and ferrites have the application defects of poor corrosion resistance and large mass density. Carbon materials are light and reliable, widely available, and have a wide relative absorption frequency band, but the impedance mismatch caused by high conductivity will greatly affect the performance of electromagnetic wave absorption. Relatively speaking, wave-transparent materials without wave-absorbing capacity, such as most insulators, such as traditional plastics such as polyvinyl chloride and polyethylene, common resins such as epoxy resin, and quartz glass, are often used as reinforcing bodies to improve the performance of wave-absorbing materials. The principle is to introduce insulators into conductive wave-absorbing materials to reduce the relative permittivity of the material to achieve impedance matching and improve the wave-absorbing characteristics of different frequency bands. In this regard, insulator-based composite materials can improve the relative permittivity by obtaining and enhancing electromagnetic parameters to achieve the transformation from wave-transparency to wave-absorption, providing more research directions for insulator-based materials to obtain electromagnetic wave absorption capacity. SUMMARY

[0004] The application aims to solve the problem of traditional insulator material boron nitride without electromagnetic wave absorption capacity, and provides an in-situ composite preparation method of calcium phosphate / boron nitride high-temperature wave-absorbing material.

[0005] An in-situ composite preparation method of calcium phosphate / boron nitride high-temperature wave-absorbing material is realized by the following steps:

[0006] I. Dissolve anhydrous calcium chloride in anhydrous ethanol and ultrasonically oscillate until uniform to obtain a mixed solution A, dissolve phosphoric acid in anhydrous ethanol, add a low-nitrogen atom fatty amine organic compound and stir until uniform to obtain a mixture B, then mix the mixture A and the mixture B and continuously stir to generate a transparent or translucent Ca3(PO4)2 ion oligomer-containing solution;

[0007] II. The above Ca3(PO4)2 ion oligomer is centrifuged to obtain a white gel, the white gel is washed twice with a low-carbon-atom saturated fatty alcohol organic compound and centrifuged to obtain a pure white Ca3(PO4)2 ion oligomer gel;

[0008] III. Boric acid and melamine are mixed and dissolved in a mixed solution of a low-carbon-atom saturated fatty alcohol organic compound and deionized water, and then heated and stirred in a heat-collecting magnetic stirrer until uniform to obtain a transparent hot solution of melamine diborate;

[0009] IV. The above pure white Ca3(PO4)2 ion oligomer gel is mixed with the transparent hot solution of melamine diborate while hot, and after cooling, centrifugation and drying, sintering is carried out in an argon atmosphere to obtain a calcium phosphate / boron nitride high-temperature wave-absorbing material, thus completing the preparation method.

[0010] Further, the ratio of the anhydrous calcium chloride, phosphoric acid, low-nitrogen-atom fatty amine organic compound and anhydrous ethanol in step I is (0.222-2.664) g:(0.131-1.572) g:(4.048-24.29) g:(30-80) mL.

[0011] Further, the low-nitrogen-atom fatty amine organic compound in step I is methylamine, dimethylamine, diethylamine or triethylamine.

[0012] Further, the low-carbon-atom saturated fatty alcohol organic compound in step II is tert-butyl alcohol, n-butyl alcohol, isobutyl alcohol or propyl alcohol.

[0013] Further, the low-carbon-atom saturated fatty alcohol organic compound used to wash the white gel in step II is in a ratio of (120-240) mL:(40-80) mL.

[0014] Further, the centrifugation in step II is at 6000-8000 r / min for 5-10 min.

[0015] Further, the ratio of the boric acid, melamine, low-carbon-atom saturated fatty alcohol organic compound and deionized water in step III is (0.495-5.934) g:(0.569-6.822) g:(30-50) mL:(40-80) mL.

[0016] Further, the heating and stirring in step III is by hydrothermal method or programmed temperature method; the temperature of the heating and stirring is 50-180°C, and the holding time is 0.5-1 h.

[0017] Further, the centrifugation in step IV is at 6000-8000 r / min for 5-10 min.

[0018] Further, the drying in step four is performed in a vacuum air drying oven at 40-60 DEG C.

[0019] Further, the sintering in an argon atmosphere in step four is performed in a tube furnace, and the temperature is raised to 1200 DEG C at a rate of 2 DEG C / min, and then kept for 3h, and then the temperature is lowered to room temperature at a rate of 2 DEG C / min.

[0020] The application of the prepared calcium phosphate / boron nitride high-temperature wave-absorbing material is to use the calcium phosphate / boron nitride high-temperature wave-absorbing material in the preparation of electromagnetic wave absorbing materials.

[0021] The process of using the calcium phosphate / boron nitride high-temperature wave-absorbing material in the preparation of electromagnetic wave absorbing materials is as follows:

[0022] After the calcium phosphate / boron nitride high-temperature wave-absorbing material and the matrix material are uniformly mixed, the mixture is poured into a mold, and then the mixture is pressed at 70-80 DEG C under a pressure of 1-10 MPa for 5 min, and then the mixture is cooled to room temperature to form an electromagnetic wave absorbing material.

[0023] The matrix material is melted paraffin, silica gel or epoxy resin.

[0024] The mass ratio of the calcium phosphate / boron nitride high-temperature wave-absorbing material to the matrix material is 3:2 or 7:3 or 4:1.

[0025] The advantages of the present application are as follows:

[0026] 1. The calcium phosphate / boron nitride high-temperature wave-absorbing material is prepared by in-situ compounding, and the preparation process is low in cost and simple, and is green and pollution-free.

[0027] 2. The calcium phosphate doping content of the material can be changed by adjusting the addition amount of anhydrous calcium chloride and phosphoric acid; the compounding of calcium phosphate can improve the electrical conductivity and magnetic permeability of the material, and improve the electromagnetic wave absorbing capacity; the calcium phosphate / boron nitride high-temperature wave-absorbing material prepared by the present application is innovative in that the wave-penetrating property of boron nitride is changed to excellent wave-absorbing property by simple compounding of inorganic non-metallic substances, the balanced electrical conductivity and polarization effect of the material cooperate with each other, and finally the high-strength and wide-band electromagnetic wave absorbing performance is realized.

[0028] 3. The preparation method of the present application can change the wave-penetrating property of boron nitride to excellent wave-absorbing property while keeping the light weight and high-temperature resistance of boron nitride; more importantly, the wave-absorbing property of boron nitride can be regulated by only changing the addition amount of reactants.

[0029] 4. With an absorption thickness of 5.5 mm, the effective absorption bandwidth (absorbing 90% of electromagnetic waves, EAB) of the calcium phosphate / boron nitride high-temperature absorbing material prepared in this invention covers 3.44-8.08 GHz and 16.88-18 GHz, achieving the goal of broadband absorption. The calcium phosphate / boron nitride high-temperature absorbing material in this invention is suitable for electromagnetic wave absorbing materials.

[0030] The calcium phosphate / boron nitride high-temperature absorbing material in this invention is suitable for the preparation of electromagnetic wave absorbing materials. Attached Figure Description

[0031] Figure 1 The image shows the XRD pattern of the calcium phosphate / boron nitride high-temperature microwave absorbing material in the examples.

[0032] Figure 2 The Fourier transform infrared spectra of the calcium phosphate / boron nitride high-temperature absorbing material and pure boron nitride in the examples are shown.

[0033] Figure 3 The images show the Raman spectra of the calcium phosphate / boron nitride high-temperature absorbing material and pure boron nitride in the examples.

[0034] Figure 4 Parts a, b, and c are SEM images of the calcium phosphate / boron nitride high-temperature absorbing material in the embodiment; parts d and e are the full TEM morphology spectrum and high-resolution image of the calcium phosphate / boron nitride high-temperature absorbing material in the embodiment, respectively.

[0035] Figure 5 The graph shows the reflection loss of the calcium phosphate / boron nitride high-temperature absorbing material in the coaxial ring sample when the mass ratio of the material to the material is 80%. ★ represents 1.5 mm, ■ represents 2 mm, ▼ represents 2.5 mm, and ▲ represents 3 mm. ◆ indicates 3.5mm, ◆ indicates 4mm, and ● indicates 4.5mm. Indicates 5mm. This indicates 5.5mm. Detailed Implementation

[0036] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0037] Specific Implementation Method 1: This implementation method provides an in-situ composite preparation method for a calcium phosphate / boron nitride high-temperature microwave absorbing material, which is achieved through the following steps:

[0038] I. The anhydrous calcium chloride is dissolved in anhydrous ethanol and ultrasonically oscillated until uniform to obtain a mixture A. The phosphoric acid is dissolved in anhydrous ethanol, then the low-nitrogen atom fatty amine organic compound is added and stirred until uniform to obtain a mixture B. Then the mixture A and the mixture B are mixed and continuously stirred to generate a transparent or translucent Ca3(PO4)2 ion oligomer-containing solution;

[0039] II. The Ca3(PO4)2 ion oligomer-containing solution is centrifuged to obtain a white gel. The white gel is washed twice with a low-carbon atom saturated fatty alcohol organic compound and centrifuged to obtain a pure white Ca3(PO4)2 ion oligomer gel;

[0040] III. The boric acid and melamine are mixed and dissolved in a co-solvent system of a low-carbon atom saturated fatty alcohol organic compound and deionized water, then heated and stirred in a heat-collecting magnetic stirrer until uniform to obtain a transparent hot solution of melamine diborate;

[0041] IV. The pure white Ca3(PO4)2 ion oligomer gel and the transparent hot solution of melamine diborate are mixed while hot, then cooled, centrifuged and dried, and sintered in an argon atmosphere to obtain a calcium phosphate / boron nitride high-temperature wave-absorbing material, thus completing the preparation method.

[0042] Specific embodiment II: The difference between this embodiment and the specific embodiment I is that the ratio of the anhydrous calcium chloride, the phosphoric acid, the low-nitrogen atom fatty amine organic compound and the anhydrous ethanol in step I is (0.222-2.664) g:(0.131-1.572) g:(4.048-24.29) g:(30-80) mL. The other steps and parameters are the same as those in the specific embodiment I.

[0043] Specific embodiment III: The difference between this embodiment and the specific embodiment I is that the low-nitrogen atom fatty amine organic compound in step I is methylamine, dimethylamine, diethylamine or triethylamine. The other steps and parameters are the same as those in the specific embodiment I.

[0044] Specific embodiment IV: The difference between this embodiment and the specific embodiment I is that the low-carbon atom saturated fatty alcohol organic compound in step II is tert-butyl alcohol, n-butyl alcohol, isobutyl alcohol or propyl alcohol. The other steps and parameters are the same as those in the specific embodiment I.

[0045] Specific embodiment V: The difference between this embodiment and the specific embodiment I is that the low-carbon atom saturated fatty alcohol organic compound used to wash the white gel in step II is: the ratio of the low-carbon atom saturated fatty alcohol organic compound to the white gel is (120-240) mL:(40-80) mL. The other steps and parameters are the same as those in the specific embodiment I.

[0046] Embodiment six: different from embodiment one, the centrifugation in step two is 6000-8000 r / min for 5-10 min. Other steps and parameters are the same as embodiment one.

[0047] Embodiment seven: different from embodiment one, the ratio of boric acid, melamine, low-carbon-atom saturated aliphatic alcohol organic compound and deionized water in step three is (0.495-5.934) g:(0.569-6.822) g:(30-50) mL:(40-80) mL. Other steps and parameters are the same as embodiment one.

[0048] Embodiment eight: different from embodiment one, the heating and stirring in step three is hydrothermal method or programmed temperature method; the temperature of the heating and stirring is 50-180℃, and the holding time is 0.5-1 h. Other steps and parameters are the same as embodiment one.

[0049] Embodiment nine: different from embodiment one, the centrifugation in step four is 6000-8000 r / min for 5-10 min. Other steps and parameters are the same as embodiment one.

[0050] Embodiment ten: different from embodiment one, the drying in step four is carried out in a vacuum air drying oven at 40-60℃. Other steps and parameters are the same as embodiment one.

[0051] Embodiment eleven: different from embodiment one, the sintering in argon atmosphere in step four is carried out in a tube furnace in argon atmosphere, with a heating rate of 2℃ / min to 1200℃, and holding for 3 h, and then a cooling rate of 2℃ / min to room temperature. Other steps and parameters are the same as embodiment one.

[0052] Embodiment twelve: the application of the prepared calcium phosphate / boron nitride high-temperature wave-absorbing material is to prepare electromagnetic wave-absorbing materials.

[0053] Embodiment thirteen: different from embodiment twelve, the process of using the calcium phosphate / boron nitride high-temperature wave-absorbing material to prepare electromagnetic wave-absorbing materials is as follows:

[0054] After mixing the calcium phosphate / boron nitride high-temperature wave-absorbing material with the matrix material, pouring into a mold, then pressurizing at 70-80℃ under 1-10 MPa, holding for 5 min, and then cooling to room temperature to form, an electromagnetic wave-absorbing material is obtained;

[0055] The base material is molten paraffin wax, silica gel or epoxy resin. Other steps and parameters are the same as in Embodiment 12.

[0056] Embodiment 14: The embodiment is different from Embodiment 13 in that the mass ratio of the calcium phosphate / boron nitride high-temperature wave-absorbing material to the base material is 3:2 or 7:3 or 4:1. Other steps and parameters are the same as in Embodiment 13.

[0057] The beneficial effects of the present application are verified by the following examples:

[0058] Example:

[0059] A method for in-situ composite preparation of a calcium phosphate / boron nitride high-temperature wave-absorbing material is implemented in the following steps:

[0060] I. Dissolve anhydrous calcium chloride in anhydrous ethanol and ultrasonically oscillate until uniform to obtain a mixed solution A. Dissolve phosphoric acid in anhydrous ethanol, add triethylamine and stir until uniform to obtain a mixture B. Then mix the mixture A and the mixture B and continuously stir to generate a transparent or translucent Ca3(PO4)2 ion oligomer-containing solution;

[0061] II. Centrifuge the Ca3(PO4)2 ion oligomer-containing solution to obtain a white gel. Wash the white gel with tert-butyl alcohol twice and centrifuge to obtain a pure white Ca3(PO4)2 ion oligomer gel;

[0062] III. Mix boric acid and melamine and dissolve in a co-solvent system of tert-butyl alcohol and deionized water to obtain a transparent hot solution of melamine diborate. Heat and stir in a heat-collecting magnetic stirrer until uniform.

[0063] IV. Mix the pure white Ca3(PO4)2 ion oligomer gel and the transparent hot solution of melamine diborate while hot, cool, centrifuge and dry, and sinter in an argon atmosphere to obtain a calcium phosphate / boron nitride high-temperature wave-absorbing material, thus completing the preparation method.

[0064] The ratio of the anhydrous calcium chloride, phosphoric acid, triethylamine and anhydrous ethanol in Step I of the embodiment is 1.332 g: 0.786 g: 8.095 g: 48 mL.

[0065] In Step II of the embodiment, the white gel is washed with tert-butyl alcohol at a ratio of 150 mL: 50 mL.

[0066] In Step II of the embodiment, the centrifugation is performed at 7000 r / min for 5 min.

[0067] The ratio of boric acid, melamine, tert-butyl alcohol and deionized water in step three of the embodiment is 0.989 g: 1.137 g: 38 mL: 44 mL.

[0068] The heating and stirring in step three of the embodiment is a hydrothermal method; the temperature of the heating and stirring is 85-90°C, and the holding time is 0.8 h.

[0069] The centrifugation in step four of the embodiment is performed at 7000 r / min for 5 min.

[0070] The drying in step four of the embodiment is performed in a vacuum air drying oven at 50°C.

[0071] The sintering in an argon atmosphere in step four of the embodiment is performed in a tube furnace in an argon atmosphere, the temperature is increased to 1200°C at a rate of 2°C / min, and then held for 3 h, and then decreased to room temperature at a rate of 2°C / min.

[0072] The calcium phosphate / boron nitride high-temperature wave-absorbing material prepared in the embodiment is subjected to X-ray diffraction phase analysis (XRD); the characterization instrument used is a DX-2700 type X-ray diffractometer produced by Dandong Haoyuan Analysis Instrument Co., Ltd., China, and the scanning speed is set to 5° / min, and the scanning range is 10°-90°. The characterization test results are shown in Figure 1 By comparison with the standard PDF card, the calcium phosphate / boron nitride high-temperature wave-absorbing material prepared in the embodiment is a composite material of BN and Ca3(PO4)2, which is consistent with the PDF card of boron nitride (PDF #00-034-0421) and the PDF card of calcium phosphate (PDF #04-010-6314).

[0073] The calcium phosphate / boron nitride high-temperature wave-absorbing material is subjected to Fourier infrared spectroscopy characterization (FT-IR); the equipment used is a Nicolet 380 type FT-IR tester of Thermo Fisher Company, USA, and the scanning wave number range is 500-4000 cm -1 ; the results are shown in Figure 2 The comparison of the infrared spectrum of the calcium phosphate / boron nitride high-temperature wave-absorbing material with the infrared spectrum of pure boron nitride shows that the two absorption peaks at about 1385 cm -1 and 780 cm -1 are respectively the in-plane stretching vibration of B-N and the out-of-plane bending vibration of B-N-B, so the Fourier infrared characterization result further proves the generation of boron nitride. The FTIR of boron nitride shows that the calcium phosphate / boron nitride high-temperature wave-absorbing material has a characteristic peak at about 1020 cm -1 , which corresponds to a small amount of residual phosphate, and it is speculated that the material is calcium phosphate, which is matched with the XRD result. At 2450 cm -1The absorption peak at that point is related to the presence of -NH and corresponds to the NH swing mode.

[0074] Raman spectroscopy characterization was performed on the calcium phosphate / boron nitride high-temperature absorbing material. The instrument used was the inVia Qontor from Renishaw, employing a 532 nm, 100 mW laser. Qualitative analysis of functional groups was achieved by analyzing the Raman peak positions. The results are as follows: Figure 3 As shown, the Raman spectrum of the calcium phosphate / boron nitride high-temperature absorbing material is compared with that of pure boron nitride, with a difference of approximately 1371 cm⁻¹. -1 , and 1365cm -1 Strong E can be observed at this location 2g Peak, at the same time at 50cm -1 The presence of a weak peak indicates the formation of BN bonds in the sample, confirming the generation of BN. These samples E 2g The half-peak full width (FWHM) of the peak is 722 cm. -1 and 479cm -1 For polycrystalline h-BN, since the crystal domain size decreases with increasing FWHM, its E 2g Shifting to higher frequencies matches the results.

[0075] The calcium phosphate / boron nitride high-temperature absorbing material was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), using a ZEISS scanning electron microscope from MERLIN (Germany) and a JEOL-2100 transmission electron microscope from JEOL Ltd. (Japan). Figure 4 As shown in (a), 4(b), and 4(c), the microstructure of the samples consists of a porous network formed by numerous interwoven micro- and nanoribbons. The cross-sections of the micro- and nanoribbons exhibit a whisker-like structure with irregular ends and a rough surface. (Scanning electron microscopy) Figure 4 (d) Transmission electron microscopy Figure 4 (e) It is evident that the composite materials are all aggregated in a fibrous manner, with lengths mostly around a few micrometers and diameters ranging from a few to tens of nanometers. Most of the boron nitride fibers are relatively intact, while a small number of broken boron nitride fibers adhere to other fibers. The pores inside the sample are mainly mesopores and micropores, and this structure is formed by the accumulation of small h-BN single crystal particles.

[0076] To investigate the electromagnetic wave absorption performance of the calcium phosphate / boron nitride high-temperature absorbing material, the powder sample to be tested (i.e., the calcium phosphate / boron nitride high-temperature absorbing material prepared in this embodiment) was uniformly mixed with molten paraffin at a mass ratio of 4:1. The mixture was then poured into a mold and pressurized at 80°C for 5 minutes. After cooling to room temperature, a coaxial sample of the electromagnetic wave absorbing material was obtained, with an outer diameter of 7 mm, an inner diameter of 3 mm, and a thickness of 2–3 mm. During the testing process, a vector network analyzer was used to acquire electromagnetic parameters, with a test frequency range of 2–18 GHz. The reflection loss value of the calcium phosphate / boron nitride high-temperature absorbing material with an absorber thickness of 1–5.5 mm was calculated. Figure 5 As shown, when the absorbent thickness is 4.5 mm, the effective absorption bandwidth, i.e., the range with a reflection loss value <-10 dB, reaches 2 GHz (6.8–8.8 GHz), with a minimum reflection loss value of -13.29 dB, corresponding to a frequency of 7.68 GHz. When the absorbent thickness is 5 mm, the effective absorption bandwidth reaches 4.8 GHz (3.76–8.56 GHz), with a minimum reflection loss value of -21.47 dB, corresponding to a frequency of 7.44 GHz. When the absorbent thickness is 5.5 mm, the effective absorption bandwidth is 5.36 GHz (3.44–8.08 GHz, 16.88–18 GHz), with a maximum reflection loss value of -41.82 dB, corresponding to a frequency of 6.96 GHz. Therefore, as the absorbent thickness changes from 4.5 mm to 5.5 mm, the material's effective absorption frequency band is manifested in the low-frequency region, with strong absorption (-41.82 dB) and wideband absorption characteristics observed at 5.5 mm.

Claims

1. An in-situ composite preparation method of calcium phosphate / boron nitride high-temperature wave-absorbing material, characterized in that It is carried out in the following steps: I. Dissolve anhydrous calcium chloride in anhydrous ethanol and ultrasonically oscillate until uniform to obtain a mixture A. Dissolve phosphoric acid in anhydrous ethanol, then add low-nitrogen atom saturated fatty amine organic compound and stir until uniform to obtain a mixture B. Then mix the mixture A and the mixture B and continuously stir to generate transparent or translucent Ca3(PO4)2 ion oligomer-containing solution; II. Centrifuge the Ca3(PO4)2 ion oligomer-containing solution to obtain white gel. Wash the white gel with low-carbon atom saturated fatty alcohol organic compound twice and centrifuge to obtain pure white Ca3(PO4)2 ion oligomer gel; III. Mix boric acid and melamine and dissolve in a co-solvent system of low-carbon atom saturated fatty alcohol organic compound and deionized water, then heat and stir in a heat collecting magnetic stirrer until uniform to obtain transparent hot solution of melamine diborate; IV. Mix the pure white Ca3(PO4)2 ion oligomer gel and the transparent hot solution of melamine diborate while hot, cool, centrifuge and dry, then sinter in an argon atmosphere to obtain calcium phosphate / boron nitride high-temperature wave-absorbing material, thus completing the preparation method; The ratio of the anhydrous calcium chloride, phosphoric acid, low-nitrogen atom saturated fatty amine organic compound and anhydrous ethanol in step I is (0.222~2.664)g:(0.131~1.572)g:(4.048~24.29)g:(30~80)mL; The low-nitrogen atom saturated fatty amine organic compound in step I is methylamine, dimethylamine, diethylamine or triethylamine; The low-carbon atom saturated fatty alcohol organic compound in step II is tert-butyl alcohol, n-butyl alcohol, isobutyl alcohol or propyl alcohol; The ratio of the boric acid, melamine, low-carbon atom saturated fatty alcohol organic compound and deionized water in step III is (0.495~5.934)g:(0.569~6.822)g:(30~50)mL:(40~80)mL; The heating and stirring in step III is hydrothermal method or programmed temperature method; the temperature of the heating and stirring is 50~180℃, and the temperature is maintained for 0.5~1h; The sintering in an argon atmosphere in step IV is carried out in a tube furnace in an argon atmosphere, the temperature is increased to 1200℃ at a rate of 2℃ / min, and the temperature is maintained for 3h, then the temperature is decreased to room temperature at a rate of 2℃ / min.

2. The in-situ composite preparation method of the calcium phosphate / boron nitride high-temperature wave-absorbing material according to claim 1, characterized in that The centrifugation in step II is carried out at 6000~8000r / min for 5~10min.

3. The in-situ composite preparation method of the calcium phosphate / boron nitride high-temperature wave-absorbing material according to claim 1, characterized in that The centrifugation in step IV is carried out at 6000~8000r / min for 5~10min.

4. The use of the calcium phosphate / boron nitride high-temperature wave-absorbing material prepared by the in-situ composite preparation method of claim 1, characterized in that The calcium phosphate / boron nitride high-temperature wave-absorbing material is used for preparing electromagnetic wave absorbing material.

Images