Aircraft tail high-temperature-resistant signal transmission cable and preparation method thereof

Abstract

The application discloses an aircraft tail high-temperature-resistant signal transmission cable and a preparation method thereof, and relates to the technical field of electromagnetic shielding signal transmission cables. The specific preparation method is as follows: firstly, fluorosilicone rubber, boron nitride and silicon carbide whiskers are uniformly mixed, then dicumyl peroxide is added and continuously mixed to obtain a mixing rubber; the mixing rubber is extruded and coated on a center conductor to form an insulation layer; then, silver-plated glass fibers are used as braiding materials, and a slant braiding process is adopted to coat the outer surface of the insulation layer to form a high-density electromagnetic shielding layer; after polyimide resin is melted, a silane coupling agent is added and reacted, then high-temperature-resistant composite particles and hexagonal boron nitride nanosheets are added in sequence and are dispersed at a high speed in an inert atmosphere; the obtained mixture is coated on the surface of the electromagnetic shielding layer by electrostatic spraying, and then solidification is carried out to form an outer protective layer; finally, the obtained cable is subjected to heat setting treatment, and the signal transmission cable is obtained. The signal transmission cable prepared by the application has good high-temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding signal transmission cables, and in particular to a high-temperature resistant signal transmission cable for an aircraft tail and a preparation method thereof. Background Art

[0002] In the aerospace industry, the safe flight and efficient operation of aircraft rely on the coordinated operation of various systems, among which the signal transmission cables at the tail of the aircraft play a key role. However, this area has long faced extremely harsh high-temperature environmental challenges.

[0003] From the perspective of the power system, the aircraft engine, as the core power source, generates intense high-temperature radiation during operation. This radiation continuously transfers heat to the tail area, causing the tail temperature to rise sharply. Simultaneously, heat conduction within the engine exacerbates the high tail temperature, typically maintaining a stable temperature above 300°C. From an aerodynamic perspective, when an aircraft flies at high speed in the atmosphere, the tail is subject to intense friction with the air. When the flight speed reaches supersonic speed, especially at high Mach numbers such as Mach 5 and above, the air is strongly compressed, generating a large amount of heat that further increases the tail temperature. According to relevant research and actual flight data monitoring, at high-speed flight conditions of Mach 10, the surface temperature of the aircraft's tail can reach 500°C-800°C. This high temperature caused by air friction and compression is a challenge that the signal transmission cables of the aircraft's tail must overcome.

[0004] Currently, conventional signal transmission cables struggle to operate reliably in the high-temperature environment found at the tail of an aircraft. Ordinary cables often use materials such as polyvinyl chloride (PVC) and polyethylene (PE) for insulation and protective layers, with a typical upper temperature limit of around 105°C. Under the high temperatures found at the tail of an aircraft, these materials rapidly soften and melt, dramatically degrading insulation performance and easily causing short circuit failures, seriously threatening aircraft flight safety. Even some cables advertised as heat-resistant, often using materials such as fluoroplastics for their protective layers, have improved their upper temperature limit, typically around 260°C. However, these cables still present numerous challenges under the long-term or transient high temperatures found at the tail of an aircraft. For example, the material gradually ages, reducing its mechanical strength and leading to poor cable structural stability. Furthermore, signal transmission can experience increased attenuation, leading to deviations in flight attitude monitoring signals and delays or errors in the transmission of powertrain control commands. This poses a significant risk for aircraft requiring high-precision control and real-time signal transmission. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-temperature resistant signal transmission cable for the tail of an aircraft and a method for preparing the same, so as to solve the technical problems raised by the above-mentioned background technology. The signal transmission cable prepared by the present invention has good high-temperature resistance.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high-temperature resistant signal transmission cable for the tail of an aircraft comprises a central conductor and a multi-layer composite protective sheath, wherein the multi-layer composite protective sheath comprises, from the inside to the outside, an insulating layer, an electromagnetic shielding layer and an outer protective layer.

[0008] Preferably, the central conductor is formed by twisting nickel-plated copper alloy wires.

[0009] Preferably, the insulating layer comprises the following components in parts by weight:

[0010] 60-70 parts of fluorosilicone rubber, 20-30 parts of boron nitride, 3-6 parts of dicumyl peroxide, and 5-10 parts of silicon carbide whiskers.

[0011] Preferably, the electromagnetic shielding layer is made of silver-plated glass fiber.

[0012] Preferably, the outer protective layer comprises the following components in parts by weight:

[0013] 70-80 parts of polyimide resin, 10-20 parts of high temperature resistant composite particles, 1-3 parts of hexagonal boron nitride nanosheets, and 0.5-1.5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0014] Preferably, the method for preparing the high temperature resistant composite particles comprises the following steps:

[0015] a) ZrOCl2 and Y(NO3)3 were added to deionized water and stirred to dissolve, and then ammonia was added dropwise to adjust the pH to alkaline to form a white precipitate. After filtration, drying, calcination and ball milling, yttria-stabilized tetragonal zirconia nanopowder was obtained;

[0016] b) Yttria-stabilized tetragonal zirconia nanopowders are mixed with Sc2O3-Al2O3 composite powders, followed by ball milling with ethanol, spray drying, and sintering to obtain Sc-Al doped zirconia;

[0017] c) adding Ti3AlC2 powder to a hydrofluoric acid solution, stirring the reaction, centrifuging, washing, and drying to obtain acid-etched Ti3AlC2, adding the acid-etched Ti3AlC2 to a Ce(NO3)3 ethanol solution, ultrasonically treating, and then drying and calcining to obtain CeO2@Ti3AlC2;

[0018] d) Yb(NO3)3, Er(NO3)3 and ethyl orthosilicate are added to an ethanol / water mixed solvent and stirred to dissolve. A nitric acid catalyst is added and heated with stirring to react to form a transparent sol. The transparent sol is transferred to a high-pressure reactor for a hydrothermal reaction. After the reaction, the mixture is centrifuged, washed and calcined to obtain nanorod-shaped Yb2SiO5 / Er2Si2O7.

[0019] e) Sc-Al doped zirconia, CeO2@Ti3AlC2 and nanorod-shaped Yb2SiO5 / Er2Si2O7 were added to a ball mill, followed by anhydrous ethanol, ball milling, spray drying and sintering in a spark plasma sintering furnace to obtain high temperature resistant composite particles.

[0020] In the technical solution of the present invention, the high temperature resistance of the outer protective layer of the polyimide resin is improved by adding high temperature resistant composite particles to the outer protective layer. First, yttrium stabilized zirconia nanopowder is synthesized by co-precipitation. After mixing ZrOCl2 and Y(NO3)3 solutions, ammonia water is added dropwise to form a Zr / Y hydroxide co-precipitation, and yttrium oxide stabilized tetragonal zirconia nanopowder is obtained after calcination. This process provides a key high temperature resistant reinforcing phase for the polyimide resin: yttrium oxide stabilized tetragonal zirconia nanopowder has extremely high thermal stability, and its nanometer size can be evenly dispersed in the resin matrix; at the same time, Y 3+ The doped tetragonal zirconia can absorb energy through phase transition at high temperatures, inhibiting the thermal degradation of polyimide molecular chains and increasing the thermal degradation temperature of polyimide. Sc2O3-Al2O3 composite powder is then evenly mixed with yttria-stabilized tetragonal zirconia nanopowder by ball milling, and Sc-Al co-doped zirconia is obtained by spray drying and sintering. This material enhances the high-temperature resistance of polyimide in two aspects: Sc 3+ -Al 3+ Composite doping increases the grain boundary energy of zirconia by 20%, forming more stable heterogeneous nucleation points in the polyimide matrix, and inhibiting the high-temperature flow of the resin; at the same time, the thermal conductivity of the doped zirconia is improved, which can quickly dissipate the heat accumulated in the polyimide at high temperatures and avoid performance degradation caused by local overheating.

[0021] Next, Ti3AlC2 is etched with hydrofluoric acid to facilitate subsequent bonding with CeO2, which is then impregnated and calcined in a Ce(NO3)3 solution to yield CeO2@Ti3AlC2. The layered structure of Ti3AlC2 blocks oxygen diffusion, slowing the high-temperature oxidation of polyimide. The surface-loaded CeO2 nanoparticles possess excellent oxygen vacancy formation, capturing free radicals that attack the polyimide molecular chain at high temperatures, further enhancing its high-temperature resistance.

[0022] Finally, rare earth silicate nanorods were synthesized by sol-gel-hydrothermal method. 3+and Er 3+ It forms a sol with tetraethyl orthosilicate under the catalysis of nitric acid, and generates nanorods with a diameter of 50 to 80 nm through hydrothermal reaction, such as Figure 1 The electron scanning electron microscope image of the nanorod-shaped Yb2SiO5 / Er2Si2O7 prepared by the present invention clearly shows that the Yb2SiO5 / Er2Si2O7 presents a rod-like structure. The high aspect ratio of the nanorods allows them to form a three-dimensional network in the resin, which increases the tortuosity of the thermal decomposition path and significantly slows down the diffusion of oxygen and heat at high temperatures. At the same time, through the Yb 3+ / Er 3+ The directional coordination effect with the polyimide imide ring guides the material to undergo controllable structural reorganization, forming a nano-composite protective layer with a nano-scale ordered structure, and synergistically improving the high-temperature resistance of the cable outer protective layer.

[0023] Preferably, in step b), the method for preparing the Sc2O3-Al2O3 composite powder comprises the following steps:

[0024] Adding scandium nitrate and aluminum nitrate into deionized water, stirring and dissolving, to obtain a mixed solution;

[0025] Ammonia water is slowly added dropwise to the mixed solution in a constant temperature water bath, and the mixture is stirred for reaction. After aging, centrifugal separation, washing and drying, Sc2O3-Al2O3 precursor powder is obtained;

[0026] The Sc2O3-Al2O3 precursor powder is calcined to obtain Sc2O3-Al2O3 composite powder.

[0027] Preferably, in step d), the mass ratio of Yb(NO3)3 to Er(NO3)3 is 1:0.5-1.

[0028] Preferably, in the step e), the mass ratio of Sc-Al doped zirconia, CeO2@Ti3AlC2 and nanorod-shaped Yb2SiO5 / Er2Si2O7 is 10:4-5:6-7.

[0029] A method for preparing a high-temperature resistant signal transmission cable for the tail of an aircraft comprises the following steps:

[0030] The fluorosilicone rubber, boron nitride and silicon carbide whiskers are first mixed uniformly, and then dicumyl peroxide is added and continued to be mixed to obtain a rubber mixture; the rubber mixture is extruded and coated on the central conductor to form an insulating layer;

[0031] Silver-plated glass fiber is used as the weaving material and is covered on the outer surface of the insulation layer using a diagonal weaving process to form a high-density electromagnetic shielding layer;

[0032] After the polyimide resin is melted, a silane coupling agent is added to react, and then high-temperature resistant composite particles and hexagonal boron nitride nanosheets are added in sequence and dispersed at high speed under an inert atmosphere; the resulting mixture is electrostatically sprayed on the surface of the electromagnetic shielding layer and then cured to form an outer protective layer; finally, the resulting cable is heat-set to obtain the cable.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The cable has electromagnetic shielding function. Its electromagnetic shielding layer is woven from silver-plated glass fiber, which can reduce the impact of external electromagnetic interference on signal transmission and ensure the stability of signal transmission.

[0035] 2. The transmission cable has good high temperature resistance. By adding high temperature resistant composite particles to the outer protective layer, the stability and resistance to thermal degradation of the cable in high temperature environment are effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the SEM image of nanorod-shaped Yb2SiO5 / Er2Si2O7 prepared in the present invention. DETAILED DESCRIPTION

[0037] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] Example 1

[0039] A high-temperature resistant signal transmission cable for the tail of an aircraft comprises a central conductor and a multi-layer composite protective sheath, wherein the multi-layer composite protective sheath comprises, from the inside to the outside, an insulating layer, an electromagnetic shielding layer and an outer protective layer.

[0040] The central conductor is formed by twisting nickel-plated copper alloy wires.

[0041] The insulating layer comprises the following components in parts by weight:

[0042] 65 parts of fluorosilicone rubber, 25 parts of boron nitride, 5 parts of dicumyl peroxide, and 7 parts of silicon carbide whiskers.

[0043] The electromagnetic shielding layer is made of silver-plated glass fiber.

[0044] The outer protective layer comprises the following components in parts by weight:

[0045] 75 parts of polyimide resin, 15 parts of high temperature resistant composite particles, 2 parts of hexagonal boron nitride nanosheets, and 1 part of γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0046] Preparation of high temperature resistant composite particles:

[0047] Step 1: Weigh 10g ZrOCl2•8H2O and 0.8g Y(NO3)3•6H2O, add them to 500mL deionized water, and stir until dissolved; add 25% ammonia water to adjust the pH to 10 to form a white precipitate, and let it stand for 24 hours; filter and separate the precipitate, wash it three times with deionized water, and dry it at 110℃ for 10 hours; place the dried powder in a muffle furnace, calcine it at 1100℃ for 2 hours, and after cooling, put it into a ball mill with agate balls as the grinding medium (ethanol medium, ball-to-material ratio 5:1), and ball mill for 2 hours to obtain yttria-stabilized tetragonal zirconia nanopowder.

[0048] Step 2: Weigh 1.0 g of scandium nitrate and 1.5 g of aluminum nitrate, add them to 150 mL of deionized water, and stir until completely dissolved; place the mixture in a constant temperature water bath at 60°C, slowly add 25% ammonia water, adjust the pH to 8.5, and stir while adding (speed 200 rpm). After the addition is completed, continue the reaction for 1 hour; let it stand for 24 hours, centrifuge (speed 5000 rpm, 10 minutes), wash the precipitate with deionized water until it is neutral, and dry it at 80°C for 12 hours to obtain a precursor powder; place the precursor in a muffle furnace, calcine at 900°C for 2 hours, and grind it after cooling to obtain Sc2O3-Al2O3 composite powder.

[0049] Take 10g of yttria-stabilized tetragonal zirconia nanopowder, mix it with 2g of Sc2O3-Al2O3 composite powder, add 20mL of ethanol, and ball mill it in a planetary ball mill at 400rpm for 4 hours; the milled slurry is spray dried (inlet temperature 180℃, outlet temperature 80℃) to obtain dry particles; the particles are placed in a muffle furnace, sintered at 1200℃ for 2 hours, and ground after cooling to obtain Sc-Al doped zirconia.

[0050] Step 3: Weigh 5.0g Ti3AlC2 powder, add it to 100mL 3mol / L hydrofluoric acid solution, stir and react at room temperature for 24 hours; centrifuge (8000rpm, 15 minutes), wash with deionized water until the filtrate pH = 6, and vacuum dry at 60℃ for 8 hours to obtain acid-etched Ti3AlC2; weigh 1.0g Ce(NO3)3•6H2O, dissolve it in 100mL ethanol, add the above acid-etched Ti3AlC2, and ultrasonically treat it for 30 minutes (power 300W); dry it at 80℃ for 6 hours, and then calcine it at 500℃ in a muffle furnace for 2 hours (heating rate 5℃ / min) to obtain CeO2@Ti3AlC2.

[0051] Step 4: Weigh 2.0g Yb(NO3)3•5H2O and 1.82g Er(NO3)3•5H2O, add them to a mixed solvent of 150mL ethanol and 150mL deionized water, and stir to dissolve; add 3.2g ethyl orthosilicate, stir for 10 minutes, then add 5mL 0.1mol / L nitric acid, heat and stir at 60℃ for 2 hours to form a transparent sol; transfer the sol to a high-pressure reactor and hydrothermally react at 180℃ for 24 hours; after cooling, centrifuge (6000rpm, 10 minutes), wash with ethanol three times, dry at 80℃ for 10 hours, and then calcined at 800℃ in a muffle furnace for 2 hours to obtain nanorod-shaped Yb2SiO5 / Er2Si2O7.

[0052] Step 5: Weigh 10g of Sc-Al-doped zirconia, 4.73g of CeO2@Ti3AlC2, and 6.85g of nanorod-shaped Yb2SiO5 / Er2Si2O7, add them to a ball mill, add 50mL of anhydrous ethanol, and ball mill for 2 hours; after spray drying (inlet temperature 170°C, outlet temperature 70°C), place them in a spark plasma sintering furnace and sinter them at 30MPa pressure and 1000°C for 10 minutes. After cooling, grind to obtain high-temperature resistant composite particles.

[0053] A method for preparing a high-temperature resistant signal transmission cable for the tail of an aircraft comprises the following steps:

[0054] A nickel-plated copper alloy wire with a diameter of 0.1 mm (nickel plating thickness of 5 μm) was prepared by twisting 19 strands with a twist pitch of 10 mm to obtain a center conductor with a diameter of 0.5 mm for later use.

[0055] Fluorosilicone rubber, boron nitride, and silicon carbide whiskers were weighed and added to an internal mixer. Mixing was carried out at 120°C and 30 rpm for 30 minutes. Dicumyl peroxide was then added and mixing continued at the same temperature and speed for 20 minutes to obtain the insulating rubber compound. The rubber compound was then extruded and coated onto the center conductor at 130°C to a thickness of 0.3 mm. The insulation layer was formed after natural cooling.

[0056] Silver-plated glass fiber with a diameter of 0.05 mm (silver plating thickness of 3 μm) is selected and woven on the outer surface of the insulation layer using a diagonal weaving process with a weaving angle of 45° and a weaving density of ≥90% to form an electromagnetic shielding layer with a thickness of 0.2 mm.

[0057] Polyimide resin was weighed and placed in a melting kettle, heated to 300°C (under nitrogen protection). γ-(2,3-epoxypropyloxy)propyltrimethoxysilane was added and stirred for 30 minutes at 500 rpm. High-temperature-resistant composite particles and hexagonal boron nitride nanosheets were then added, followed by high-speed dispersion at 3000 rpm in an inert atmosphere (argon) for 30 minutes to form the outer protective coating. The coating was then applied to the electromagnetic shielding layer using an electrostatic spraying process (30 kV, spraying distance 20 cm) to a thickness of 0.5 mm. The coating was then cured in a 200°C oven for 2 hours. Finally, the entire cable was heat-set in a 150°C oven for 1 hour to produce the high-temperature-resistant signal transmission cable for the aircraft tail.

[0058] Example 2

[0059] The difference between Example 2 and Example 1 lies in the following process of preparing the high temperature resistant composite particles:

[0060] In step 4, weigh 2.0 g Yb(NO3)3•5H2O and 1.36 g Er(NO3)3•5H2O;

[0061] In step 5, 10 g of Sc-Al doped zirconia, 4.20 g of CeO2@Ti3AlC2 and 6.18 g of nanorod-shaped Yb2SiO5 / Er2Si2O7 were weighed.

[0062] Example 3

[0063] The difference between Example 3 and Example 1 lies in the following process of preparing the high temperature resistant composite particles:

[0064] In step 4, weigh 2.0 g Yb(NO3)3•5H2O and 1.50 g Er(NO3)3•5H2O;

[0065] In step 5, 10 g of Sc-Al doped zirconia, 4.50 g of CeO2@Ti3AlC2 and 6.50 g of nanorod-shaped Yb2SiO5 / Er2Si2O7 were weighed.

[0066] Example 4

[0067] The difference between Example 4 and Example 1 is that:

[0068] The insulating layer comprises the following components in parts by weight:

[0069] 70 parts of fluorosilicone rubber, 30 parts of boron nitride, 6 parts of dicumyl peroxide, and 10 parts of silicon carbide whiskers.

[0070] The outer protective layer comprises the following components in parts by weight:

[0071] 80 parts of polyimide resin, 20 parts of high temperature resistant composite particles, 3 parts of hexagonal boron nitride nanosheets, and 1.5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0072] In step 4, weigh 2.0 g of Yb(NO3)3•5H2O and 2.0 g of Er(NO3)3•5H2O;

[0073] In step 5, 10 g of Sc-Al doped zirconia, 5 g of CeO2@Ti3AlC2 and 7 g of nanorod-shaped Yb2SiO5 / Er2Si2O7 were weighed.

[0074] Example 5

[0075] The difference between Example 5 and Example 1 is that:

[0076] The insulating layer comprises the following components in parts by weight:

[0077] 60 parts of fluorosilicone rubber, 20 parts of boron nitride, 3 parts of dicumyl peroxide, and 5 parts of silicon carbide whiskers.

[0078] The outer protective layer comprises the following components in parts by weight:

[0079] 70 parts of polyimide resin, 10 parts of high temperature resistant composite particles, 1 part of hexagonal boron nitride nanosheets, and 0.5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0080] In step 4, weigh 2.0 g Yb(NO3)3•5H2O and 1.0 g Er(NO3)3•5H2O;

[0081] In step 5, 10 g of Sc-Al doped zirconia, 4 g of CeO2@Ti3AlC2 and 6 g of nanorod-shaped Yb2SiO5 / Er2Si2O7 were weighed.

[0082] Comparative Example 1

[0083] The difference between Comparative Example 1 and Example 1 is that the high-temperature resistant signal transmission cable at the tail of the aircraft lacks an electromagnetic shielding layer.

[0084] Comparative Example 2

[0085] The difference between Comparative Example 2 and Example 1 is that in the preparation of the high-temperature resistant composite particles, Sc-Al doped zirconia is not added during the ball milling process in step 5.

[0086] Comparative Example 3

[0087] The difference between Comparative Example 3 and Example 1 is that during the preparation of the high-temperature resistant composite particles, CeO2@Ti3AlC2 is not added during the ball milling process in step 5.

[0088] Comparative Example 4

[0089] The difference between Comparative Example 4 and Example 1 is that in the preparation of the high-temperature resistant composite particles, nanorod-shaped Yb2SiO5 / Er2Si2O7 is not added during the ball milling process in step 5.

[0090] Performance testing:

[0091] 1. High-temperature resistance test: Referring to GB / T 2951.12-2008, "General Test Methods for Cable Insulation and Sheath Materials," cable samples were placed in ovens at 500°C and 800°C for 100 hours of continuous aging. After removal, the samples were inspected for any deformation. An insulation resistance tester was used to measure the change in the insulation layer's volume resistivity (resistivity after aging / initial resistivity × 100%) to assess high-temperature stability. The test results are shown in Table 1.

[0092] 2. Electromagnetic Shielding Effectiveness Test: The shielding effectiveness (SE) of the cable was tested using a vector network analyzer in the 30MHz-1GHz frequency range, in accordance with GB / T 12190-2006, "Measurement Method of Shielding Effectiveness of Electromagnetic Shielding Chambers." The cable was placed in a shielding chamber, and the shielding effectiveness (SE) was calculated (in dB) by comparing the electromagnetic wave intensity inside the chamber with that outside. A higher value indicates better shielding effectiveness. See Table 1 for test results.

[0093] 3. High-temperature signal transmission stability test: A network analyzer was used to test the cable's transmission attenuation for 100MHz-1GHz signals at 500°C. The signal attenuation at room temperature was recorded before testing. After 100 hours of high temperature exposure, the test was repeated and the attenuation change rate was calculated (high-temperature attenuation value / room-temperature attenuation value × 100%). A value closer to 100% indicates more stable signal transmission. See Table 1 for test results.

[0094] 4. High-Temperature Tensile Strength Test: Referring to GB / T 1040.3-2006, "Plastics - Determination of Tensile Properties," standard cable outer protective layer specimens (100 mm long, 10 mm wide, 2 mm thick) were prepared. The tensile strength (unit: MPa) was measured using a universal testing machine at room temperature and after aging at 500°C for 100 hours. The high-temperature tensile strength retention was calculated to assess the ability to maintain mechanical properties at high temperatures. The test results are shown in Table 1.

[0095] Table 1:

[0096]

[0097] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature resistant signal transmission cable for the tail of an aircraft, comprising a central conductor and a multi-layer composite protective sheath, characterized in that: The multi-layer composite protective cover comprises, from the inside to the outside, an insulating layer, an electromagnetic shielding layer and an outer protective layer; The outer protective layer comprises the following components in parts by weight: 70-80 parts of polyimide resin, 10-20 parts of high temperature resistant composite particles, 1-3 parts of hexagonal boron nitride nanosheets, and 0.5-1.5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane; The preparation method of the high temperature resistant composite particles comprises the following steps: a) ZrOCl2 and Y(NO3)3 were added to deionized water and stirred to dissolve, and then ammonia was added dropwise to adjust the pH to alkaline to form a white precipitate. After filtration, drying, calcination and ball milling, yttria-stabilized tetragonal zirconia nanopowder was obtained; b) Yttria-stabilized tetragonal zirconia nanopowders are mixed with Sc2O3-Al2O3 composite powders, followed by ball milling with ethanol, spray drying, and sintering to obtain Sc-Al doped zirconia; c) adding Ti3AlC2 powder to a hydrofluoric acid solution, stirring the reaction, centrifuging, washing, and drying to obtain acid-etched Ti3AlC2, adding the acid-etched Ti3AlC2 to a Ce(NO3)3 ethanol solution, ultrasonically treating, and then drying and calcining to obtain CeO2@Ti3AlC2; d) Yb(NO3)3, Er(NO3)3 and ethyl orthosilicate are added to an ethanol / water mixed solvent and stirred to dissolve. A nitric acid catalyst is added and heated with stirring to react to form a transparent sol. The transparent sol is transferred to a high-pressure reactor for a hydrothermal reaction. After the reaction, the mixture is centrifuged, washed and calcined to obtain nanorod-shaped Yb2SiO5 / Er2Si2O7. e) Sc-Al doped zirconia, CeO2@Ti3AlC2 and nanorod-shaped Yb2SiO5 / Er2Si2O7 were added to a ball mill, followed by anhydrous ethanol, ball milling, spray drying and sintering in a spark plasma sintering furnace to obtain high temperature resistant composite particles.

2. The aircraft tail high temperature resistant signal transmission cable according to claim 1, characterized in that: The central conductor is formed by twisting nickel-plated copper alloy wires.

3. The aircraft tail high temperature resistant signal transmission cable according to claim 1, characterized in that: The insulating layer comprises the following components in parts by weight: 60-70 parts of fluorosilicone rubber, 20-30 parts of boron nitride, 3-6 parts of dicumyl peroxide, and 5-10 parts of silicon carbide whiskers.

4. The aircraft tail high temperature resistant signal transmission cable according to claim 1, characterized in that: The electromagnetic shielding layer is made of silver-plated glass fiber.

5. The aircraft tail high temperature resistant signal transmission cable according to claim 1, characterized in that: In the step b), the method for preparing the Sc2O3-Al2O3 composite powder comprises the following steps: Adding scandium nitrate and aluminum nitrate into deionized water, stirring and dissolving, to obtain a mixed solution; Ammonia water is slowly added dropwise to the mixed solution in a constant temperature water bath, and the mixture is stirred for reaction. After aging, centrifugal separation, washing and drying, Sc2O3-Al2O3 precursor powder is obtained; The Sc2O3-Al2O3 precursor powder is calcined to obtain Sc2O3-Al2O3 composite powder.

6. The aircraft tail high temperature resistant signal transmission cable according to claim 1, characterized in that: In the step d), the mass ratio of Yb(NO3)3 to Er(NO3)3 is 1:0.5-1.

7. The aircraft tail high temperature resistant signal transmission cable according to claim 1, characterized in that: In the step e), the mass ratio of Sc-Al doped zirconia, CeO2@Ti3AlC2 and nanorod-shaped Yb2SiO5 / Er2Si2O7 is 10:4-5:6-7.

8. A method for preparing a high-temperature resistant signal transmission cable for an aircraft tail as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: The fluorosilicone rubber, boron nitride and silicon carbide whiskers are first mixed evenly, and then dicumyl peroxide is added and continued to be mixed to obtain a rubber compound; Extruding the rubber mixture and coating the central conductor to form an insulating layer; Silver-plated glass fiber is used as the weaving material and is covered on the outer surface of the insulation layer using a diagonal weaving process to form a high-density electromagnetic shielding layer; After the polyimide resin is melted, a silane coupling agent is added to react, and then high-temperature resistant composite particles and hexagonal boron nitride nanosheets are added in sequence and dispersed at high speed under an inert atmosphere. The resulting mixture is electrostatically sprayed on the surface of the electromagnetic shielding layer and then cured to form an outer protective layer; finally, the resulting cable is heat-set to obtain the cable.

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