Nonlinear conductive epoxy resin composites based on metal nanoparticles and silicon carbide particle fillers, their preparation methods and applications

Abstract

This invention discloses a nonlinear conductive epoxy resin composite material constructed based on metal nanoparticles and silicon carbide particle fillers, its preparation method, and its applications. The nonlinear conductive epoxy resin composite material of this invention comprises a functional filler composed of metal nanoparticles and silicon carbide material, and an epoxy resin matrix. The metal nanoparticles, well dispersed on the surface of the silicon carbide material, guide charge transport within the composite material, forming a charge dissipation network. This novel nonlinear conductive epoxy resin composite material exhibits the ability to promptly dissipate accumulated charge under a locally enhanced DC electric field, thereby protecting equipment from electrostatic discharge and partial discharge hazards. It provides a new perspective and development direction for electronic device packaging materials and electrical equipment insulation materials. Furthermore, the material preparation process is simple, highly operable, and suitable for industrial application.

Description

Technical Field

[0001] This invention relates to the field of nonlinear conductive epoxy resin composite materials technology, specifically to a method for preparing nonlinear conductive epoxy resin composite materials based on metal nanoparticles and silicon carbide particle fillers, and their applications. Background Technology

[0002] The trend towards higher integration and power density in electronic components poses significant challenges to the insulation performance and intelligence of their packaging materials. Traditional packaging insulation materials are typically designed to improve breakdown resistance. However, due to the complexity of device structures, electric field distortion and charge injection are unavoidable. Accumulated free charges can cause electrostatic discharge or electron avalanche under prolonged operating conditions, leading to insulation failure and threatening component safety. In this context, a smart material whose electrical parameters are nonlinearly affected by the electric field strength—namely, nonlinear conductive materials—has attracted industry attention. These materials exhibit high insulation at low voltages but can rapidly release charges at high voltages, preventing insulation failure caused by localized electric field distortion. The fundamental principle of nonlinear materials is to achieve the insulation-conductivity state transition through the Schottky barrier of wide-bandgap semiconductor materials. Limited by the scarcity of wide-bandgap semiconductors (such as zinc oxide and silicon carbide), many have proposed constructing core-shell structures (such as bismuth oxide / zinc oxide, titanium dioxide / barium titanate, silicon dioxide / silicon carbide) to adjust the barrier height, hoping to obtain tunable threshold field strength and nonlinear conductivity. However, this strategy imposes stringent requirements on the conductivity of the outer shell components. On the one hand, a highly insulating shell reduces charge dissipation efficiency above the threshold electric field. On the other hand, a low-resistivity shell struggles to maintain ideal insulation below the threshold electric field because charge tends to conduct along the shell rather than through the semiconductor core. Furthermore, even when the filler content reaches the percolation threshold, a polymer matrix layer approximately 15 nanometers thick remains between adjacent fillers. This layer, typically overlooked in previous nonlinear material designs, results in an additional polymer / semiconductor interface that significantly impacts charge dissipation efficiency under high electric fields. Therefore, fabricating high-performance, parameter-tunable nonlinear conductive materials remains challenging.

[0003] Previous preparation schemes for high-performance nonlinear conductive materials, such as those disclosed in patents CN114854177B and CN115536982B, have yielded different results. CN114854177B uses a silane coupling agent to modify silicon carbide, improving its compatibility with the epoxy resin matrix. However, its nonlinear coefficient is only increased to 5.6, failing to solve the negative impact of the polymer thin layer between filler particles. CN115536982B uses dopamine and titanium dioxide to jointly modify barium carbonate particles. However, due to the shielding effect of the dopamine layer on the charge carriers in the titanium dioxide region, the performance of the prepared nonlinear conductive material is difficult to control, and it cannot meet the flexible requirements of practical applications.

[0004] In summary, solving the problem of barrier height control and suppressing the adverse effects of polymer thin layers on charge dissipation rate, it is crucial to develop a high-performance nonlinear conductivity composite material with adjustable barrier height and high nonlinear coefficient, providing a promising direction for the development of intelligent packaging materials for next-generation electronic devices. Summary of the Invention

[0005] The purpose of this invention is to provide a nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers, its preparation method, and its application.

[0006] The technical solution adopted in this invention is:

[0007] A nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers is disclosed, comprising an epoxy resin matrix and a metal nanoparticle-silicon carbide composite filler. The metal nanoparticle-silicon carbide composite filler comprises micron-sized silicon carbide microspheres and metal nanoparticles dispersed and attached to their outer surface.

[0008] Further, the volume fraction of silicon carbide is 20-25 vol%, and the volume fraction of metal nanoparticles is 0.2-0.6 vol%; the particle size of silicon carbide particles in the nonlinear conductive epoxy resin composite material constructed based on metal nanoparticles and silicon carbide particle fillers is in the range of 4-7 micrometers, and the particle size of metal nanoparticles is in the range of 8-60 nanometers.

[0009] Silver nanoparticle-silicon carbide composite filler is prepared by the following method:

[0010] 1) First, silicon carbide particles are mixed in deionized water and dispersed by ultrasonication to obtain a silicon carbide dispersion, wherein the mass fraction of silicon carbide is 0.047-0.141. Silver nitrate or gold chlorate powder is added and stirred to obtain a silicon carbide-metal salt mixed solution, which is allowed to stand for 15-60 minutes. The mass ratio of silver nitrate to silicon carbide in the mixed solution is 0.034-0.102, and the mass ratio of gold chlorate to silicon carbide is 0.068-0.204.

[0011] 2) The reaction solution was filtered and the solid was freeze-dried to obtain a composite filler with metal nanoparticles and silicon carbide particles in contact.

[0012] 3) The composite filler obtained after freeze-drying, which has metal nanoparticles and silicon carbide particles in contact, is subjected to high temperature treatment for 2-4 hours to obtain silver nanoparticle-silicon carbide composite filler in which metal nanoparticles and silicon carbide particles are in close contact.

[0013] Furthermore, in step 1), the ultrasonic dispersion time is 20-60 minutes.

[0014] Furthermore, the silicon carbide-silver nitrate mixed solution described in step 2) needs to be allowed to stand in the dark for 15-60 minutes, and then quickly filtered.

[0015] Furthermore, in step 3), the high-temperature treatment process needs to be carried out in a nitrogen atmosphere, and the heating temperature is 300-360°C, preferably 360°C.

[0016] The particle size of the obtained metal nanoparticles is controlled by the static reaction time of the silicon carbide-metal salt mixed solution, and the particle size of the metal nanoparticles is in the range of 8-60 nanometers.

[0017] The method for preparing the nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers includes the following steps: dispersing silver nanoparticle-silicon carbide composite fillers obtained at different reaction times in a mixture of epoxy resin, curing agent and accelerator for degassing and high-temperature curing to obtain the corresponding composite material.

[0018] The proportions of epoxy resin monomer, curing agent, accelerator, and metal nanoparticle-silicon carbide composite filler are as follows: 1 part epoxy resin monomer, 1-1.2 parts curing agent, 0.006-0.01 parts accelerator, and 8.2-10.28 parts metal nanoparticle-silicon carbide composite filler. The volume fraction of the metal nanoparticle-silicon carbide composite filler in the prepared composite material is 20%-25%. The epoxy resin is at least one of alicyclic epoxy resin and bisphenol A type epoxy resin; the curing agent is methylhexahydrophthalic anhydride; and the accelerator is 2-ethyl-4-methylimidazole.

[0019] Furthermore, the dispersion conditions are as follows: first, the nanoparticle-silicon carbide composite filler is ultrasonically dispersed in acetone for 30 minutes, and then epoxy resin is added and heated and stirred in an oil bath for 4 hours to evaporate the acetone.

[0020] Furthermore, the high-temperature curing conditions are as follows: first, cure at 95℃-115℃ for 40-80 minutes, then cure at 115℃-125℃ for 100-150 minutes, and then cure at 135℃-145℃ for 30-60 minutes.

[0021] The present invention prepares a nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers, wherein the volume fraction of SiC is 20-25 vol%; the volume fraction of metal nanoparticles is 0.2-0.6 vol%; and the particle size of the silicon carbide particles in the nonlinear conductive epoxy resin composite material is in the range of 4-7 micrometers. The particle size of the metal nanoparticles is in the range of 8-60 nanometers.

[0022] This invention relates to a nonlinear conductive epoxy resin composite material constructed using metal nanoparticles and silicon carbide particles. The composite material comprises an epoxy resin matrix, metal nanoparticles, and silicon carbide as a functional filler. A highly engineered solution reduction method is used to process the silicon carbide, creating metal nanoparticles of varying sizes on its surface. These well-dispersed metal nanoparticles guide charge transport within the composite material, forming a charge dissipation network that enables efficient charge dissipation under high electric fields. This nonlinear conductive epoxy resin composite material exhibits a high nonlinear coefficient, demonstrating a clear transition between insulation and conductivity under high and low electric fields. It also exhibits rapid charge dissipation under locally enhanced electric fields, preventing electrostatic discharge and partial discharge hazards caused by charge accumulation. This novel nonlinear conductive material offers a promising direction for intelligent electronic packaging, and the process is more operable, making it suitable for industrial applications. The material can also be used to prepare electronic device packaging materials.

[0023] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0024] (1) By constructing a contact between metal nanoparticles and silicon carbide, this invention directly utilizes the Schottky barrier formed by the metal-semiconductor interface, thereby enabling flexible control of the barrier height by screening metal materials.

[0025] (2) The metal nanoparticles prepared by the solution reduction method of the present invention are grown in situ on the surface of silicon carbide particles, which avoids large-scale agglomeration and does not degrade the insulation performance of the final composite material under low electric field.

[0026] (3) The metal nanoparticles used in this invention utilize the electric field near the distortion of the metal material to overcome the influence of the polymer thin layer, so that the final composite material has the ability to quickly dissipate charge under high electric field conditions, protecting the equipment from the harm of electrostatic discharge and partial discharge.

[0027] (4) The present invention achieves a nonlinear coefficient of 8.7 at a filler volume fraction of 25 vol%, exhibits rapid charge dissipation performance in electrostatic discharge tests, and effectively suppresses the amount of accumulated charge on the material surface. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the preparation process of the nonlinear conductive epoxy resin composite material based on silver metal nanoparticles and silicon carbide particle fillers of the present invention.

[0029] Figure 2 This is a SEM image of a silver metal nanoparticle-silicon carbide composite filler.

[0030] Figure 3 The ultraviolet photoelectron spectrum of the silver metal nanoparticle-silicon carbide composite filler is shown.

[0031] Figure 4 This is a post-processed image of the UV-Vis diffuse reflectance spectrum of the silver metal nanoparticle-silicon carbide composite filler.

[0032] Figure 5 The relative band structure diagrams are for silicon carbide, silver, gold, and composite fillers of silicon carbide with two metal nanoparticles.

[0033] Figure 6 The figure shows the conductivity-electric field strength test results of the composite material prepared by directly filling silicon carbide with two kinds of metal nanoparticles and silicon carbide.

[0034] Figure 7 Simulation results of the internal electric field intensity distribution and electrical conduction path of a nonlinear conductive epoxy resin composite material based on silver metal nanoparticles and silicon carbide particle fillers.

[0035] Figure 8 SEM images of silver nanoparticle-silicon carbide composite fillers with reaction growth times of 15, 40, and 60 minutes.

[0036] Figure 9 To verify the electrostatic discharge test results of the charge dissipation ability of composite materials filled with metal nanoparticles and silicon carbide composite fillers versus those directly filled with silicon carbide.

[0037] Figure 10 The conductivity-electric field strength test diagrams are for the nonlinear conductive composite materials EP-Ag40 / SiC and EP-SiC prepared in Example 2 and Comparative Example 1. Detailed Implementation

[0038] The technical solution of the present invention will be further explained below with reference to specific embodiments and accompanying drawings.

[0039] Example 1

[0040] A nonlinear conductive epoxy resin composite material based on silver metal nanoparticles and silicon carbide particle fillers is prepared by the following steps (preparation process as follows). Figure 1 (as shown)

[0041] 1) Add silicon carbide powder to deionized water and ultrasonically disperse for 45 minutes. The mass ratio of silicon carbide to deionized water is 5:100. Add silver nitrate powder to the above silicon carbide dispersion. The mass ratio of silver nitrate powder to deionized water is 0.17:100. After stirring and dissolving thoroughly, add sodium hydroxide solution with a concentration of 1 mol / L dropwise to make the pH value reach 12. Place in a dark place and let it stand for 60 minutes to react.

[0042] 2) The solution after the reaction was filtered and washed three times each with water and ethanol. It was then freeze-dried at -25°C for 24 hours. After the freeze-drying was completed, the powder sample was removed and heated in a tube furnace at 360°C in a nitrogen atmosphere for 4 hours.

[0043] 3) Repeat the above steps to obtain a sufficient amount of silver metal nanoparticle-silicon carbide composite filler. Add 20.59 g of the composite filler to 20 g of acetone and disperse by sonication for 45 minutes. Then add 10 g of alicyclic epoxy resin and heat to 70°C and stir for 4 hours to evaporate all the acetone. Add methylhexahydrophthalic anhydride and 2-ethyl-4-methylimidazole at a mass ratio of 1:1.2:0.006. Stir for 30 minutes and place in a vacuum chamber at 50°C for 5 hours to remove air bubbles from the mixture. Then place in a heating chamber and cure at 110°C for 60 minutes, then at 125°C for 120 minutes, and then at 135°C for 60 minutes to obtain a nonlinear conductive epoxy resin composite material (denoted as EP-Ag60 / SiC) based on silver metal nanoparticles and silicon carbide particles. The filler volume fraction of this composite material is 25 vol.

[0044] Example 2

[0045] A nonlinear conductive epoxy resin composite material, denoted as EP-Ag40 / SiC, is constructed based on silver metal nanoparticles and silicon carbide particle fillers. Its preparation process is the same as in Example 1, except that the reaction time of the solution in the dark is adjusted to 40 minutes in step 1).

[0046] Example 3

[0047] A nonlinear conductive epoxy resin composite material, denoted as EP-Ag15 / SiC, is constructed based on silver metal nanoparticles and silicon carbide particle fillers. Its preparation process is the same as in Example 1, except that the reaction time of the solution in the dark is adjusted to 15 minutes in step 1).

[0048] Example 4

[0049] A nonlinear conductive epoxy resin composite material based on gold nanoparticles and silicon carbide particle fillers, denoted as EP-Au60 / SiC, is prepared in the same manner as in Example 1, except that the metal particle salt added in step 1) is changed from silver nitrate to gold chlorate. The mass ratio of the added gold chlorate powder to deionized water is 0.34:100.

[0050] Comparative Example 1

[0051] An epoxy composite material directly filled with silicon carbide, the preparation method of which includes the following steps:

[0052] 20.59 g of composite filler was added to 20 g of acetone and dispersed by sonication for 45 minutes. Then, 10 g of alicyclic epoxy resin was added, and the mixture was heated to 70°C and stirred for 4 hours until all the acetone was evaporated. Methylhexane and 2-ethyl-4-methylimidazole were added at a mass ratio of 1:1.2:0.006. After stirring for 30 minutes, the mixture was placed in a vacuum chamber and evacuated at 50°C for 5 hours to remove air bubbles. Then, the mixture was placed in a heating chamber and cured at 110°C for 60 minutes, then at 125°C for 120 minutes, and then at 135°C for 60 minutes to obtain a directly filled silicon carbide epoxy resin composite material (denoted as EP-SiC). The filler volume fraction of this composite material was 25 vol.

[0053] Performance testing

[0054] 1. TEM image of the silver nanoparticle-silicon carbide composite filler prepared in Example 1 is shown below. Figure 2 As shown, the infrared spectrum is as follows Figure 3 As shown, the thermogravimetric curve is as follows Figure 4 As shown.

[0055] Depend on Figure 2 As can be seen, the high-angle annular dark-field scanning image clearly depicts the presence of silver nanoparticles attached to the silicon carbide surface. Smaller particles are uniformly spherical, while larger particles exhibit various morphologies. This phenomenon is attributed to the contact between nanoparticles that approach each other during the growth stage, resulting in the growth of irregular ellipsoidal shapes. However, overall, there is no obvious aggregation.

[0056] 2. The ultraviolet photoelectron spectra of silicon carbide and the composite fillers of silver and gold nanoparticles prepared in Examples 1 and 4 (referred to as SiC, Ag / SiC, and Au / SiC) are as follows: Figure 3 As shown.

[0057] The UV photoelectron spectroscopy obtained from SiC, Ag / SiC, and Au / SiC highlights both low and high binding energy regions. The low and high binding energy cutoff points were determined based on the corresponding tangents for each region, used to determine the Fermi level, valence band maximum, and conduction band minimum (relative to the vacuum level) for each material. The calculated Fermi level for silicon carbide is 3.01 eV. Silicon carbide composite fillers with surface metal nanoparticles exhibit higher Fermi levels due to the larger work functions of silver and gold (4.26 and 5.1, respectively), making it more difficult for electrons to be excited to the vacuum level.

[0058] 3. Post-processed UV-Vis diffuse reflectance spectra of silicon carbide and the composite fillers of silver and gold nanoparticles prepared in Examples 1 and 4 are shown in the figure. Figure 4 As shown.

[0059] The band gaps of SiC, Ag / SiC, and Au / SiC were determined through UV-Vis measurements and subsequent processing. Tauc fitting results showed that the band gaps of SiC, Ag / SiC, and Au / SiC were 2.85 eV, 2.58 eV, and 2.72 eV, respectively. Compared to Au / SiC, Ag / SiC has a smaller band gap due to the higher conductivity of silver. Ag / SiC and Au / SiC exhibited a new peak in the low photon energy range, at 1.04 eV and 1.13 eV, respectively. This peak is attributed to the stimulation of electrons from low-energy metal nanoparticle clusters.

[0060] 4. The relative band structure of silicon carbide and the composite filler of silver and gold nanoparticles prepared in Examples 1 and 4 with silicon carbide is as follows: Figure 5 As shown.

[0061] As shown in the figure, Ag / SiC and Au / SiC have higher conduction band bottoms and valence band tops than SiC. Furthermore, the Fermi levels of Ag / SiC and Au / SiC lie between the Fermi levels of silicon carbide and the metal. This is because when a heterojunction is formed at the metal-silicon carbide interface, the band structure changes due to the Fermi level alignment effect. Since silicon carbide has a weaker binding force with electrons, electrons migrate, forming a space charge region at the interface. This leads to band bending. Electrons crossing the metal-silicon carbide interface must overcome the Schottky barrier at the interface.

[0062] 5. The conductivity-electric field strength test results of the epoxy resin composite materials (i.e., EP-Ag60 / SiC, EP-Au60 / SiC, and EP-SiC) prepared in Examples 1, 4, and Comparative Example 1 are as follows: Figure 6 As shown.

[0063] The nonlinear conductivity of nonlinear conductive composite materials is typically evaluated using switching electric fields and nonlinear coefficients, which represent the potential application range and nonlinear effects. Fitting results show that the nonlinear coefficients of EP-Ag60 / SiC and EP-Au60 / SiC are 8.7 and 8.2, respectively, significantly higher than EP-SiC (7.8). Simultaneously, the switching electric fields of EP-Ag60 / SiC and EP-Au60 / SiC are 1.11 kV / mm and 1.07 kV / mm, respectively, significantly lower than EP-SiC (3 kV / mm). This improves the sensitivity of the nonlinear conductive material to electric fields, enabling more sensitive dissipation of accumulated charge. Composite materials with metal nanoparticles exhibit significantly increased conductivity, indicating higher sensitivity to electric fields. This characteristic can rapidly clear accumulated charge on the material surface, thus preventing more severe local discharge. This phenomenon can be explained by the presence of metal nanoparticles on the silicon carbide surface, which act as sensitive microcapacitor structures, significantly altering the electric field strength of nearby polymers. When electrons reach the nearest metal nanoparticle on a neighboring silicon carbide particle, they can easily hop across the polymer for conduction. Compared to composites directly filled with silicon carbide, metal nanoparticles make it easier to form complete conduction channels. The potential barrier height at the interface between the metal nanoparticles and silicon carbide plays a crucial role in nonlinear electrical properties. Interfaces with higher barrier heights require greater energy to pass through. Therefore, choosing a metal with high conductivity and low work function to construct on the semiconductor surface will result in a significant reduction in the switching electric field.

[0064] 6. The phase-field simulation results of the internal electrical processes of the EP-Ag60 / SiC composite material prepared in Example 1 under DC voltage are as follows: Figure 7 As shown.

[0065] To further investigate the influence of metal nanoparticles on the nonlinear conductivity of composite materials, we established a phase model to simulate the diffusion of electrical channels. Due to the difference in conductivity and relative permittivity between silver and the polymer material, a strong and concentrated electric field enhancement effect appears near the silver nanoparticles. Notably, the electric field distortion in the polymer region between adjacent metal nanoparticles is more significant. Therefore, electrons tend to pass through the silicon carbide via the silver nanoparticles, thus promoting the directional movement of electrons, and the largest potential barrier appears along the conduction channel at the metal-silicon carbide interface. This conclusion can be verified by the simulation results of the conductivity path.

[0066] 7. The SEM results of the silver metal nanoparticle-silicon carbide composite fillers (i.e., Ag60 / SiC, Ag40 / SiC, and Ag15 / SiC) prepared in Examples 1, 2, and 3 are as follows: Figure 8 As shown.

[0067] By changing the reaction time, silver nanoparticles of different sizes can be synthesized on the surface of silicon carbide. Figure 8 This study demonstrates a close relationship between growth time and the diameter of metal nanoparticles. Smaller diameter nanoparticles exhibit a more uniform spherical shape. This phenomenon occurs because, during the static reaction phase, silver atoms generated by ion reduction initially combine with silicon carbide. As the number of silver atoms gradually increases, the size of the nanoparticles also increases. Aggregation occurs when two adjacent silver atom clusters come into contact. Therefore, silver nanoparticles reacting for 60 minutes lose their characteristic spherical shape, while at reaction durations of 40 minutes and 15 minutes, reduced aggregation causes the nanoparticles to retain their spherical shape.

[0068] 8. The conductivity-electric field strength test results of the nonlinear conductive composite materials (i.e., EP-Ag60 / SiC, EP-Ag40 / SiC, and EP-Ag15 / SiC) prepared in Examples 1, 2, and 3 are as follows: Figure 9 As shown.

[0069] Compared to EP-Ag60 / SiC, EP-Ag40 / SiC exhibits more pronounced nonlinear conductivity, while EP-Ag15 / SiC shows the opposite trend. This phenomenon can be attributed to the fact that a large number of nanoparticles in Ag15 / SiC are smaller than the threshold scale for the Coulomb blockade effect, thus limiting electron transport processes. The nanoparticle size distribution of Ag15 / SiC was determined by a normal distribution with an average value of 13.2 nm, which is consistent with previous findings on the nanoparticle size affected by the Coulomb blockade effect.

[0070] 9. The conductivity-electric field strength test results of the nonlinear conductive composite materials (i.e., EP-Ag40 / SiC and EP-SiC) prepared in Example 2 and Comparative Example 1 are as follows: Figure 10 As shown.

[0071] To evaluate the electrostatic discharge protection capability of the proposed nonlinear conductive composite material, we verified its adaptive charge release behavior under charge pulses generated by an electrostatic discharge gun. When a discharge pulse is applied to the material surface, if the sample is in a state of increased conductivity, the charge will flow into the grounding electrode through bulk conduction. Otherwise, the charge will gradually dissipate through a bypass resistor. Therefore, the adaptive charge release characteristics of the material are mainly affected by its nonlinear conductivity, especially the switching electric field. When subjected to a 40 nC charge pulse, the electric field on the EP-Ag40 / SiC sample is 1 kV / mm, lower than the 1.2 kV / mm switching electric field. Therefore, the material is in an insulating state, and the charge dissipates slowly. Conversely, when the applied charge pulse increases to 80 nC (corresponding to an electric field strength of 2 kV / mm on the sample, exceeding the switching electric field), the conductive paths within EP-Ag40 / SiC are activated, and the conductivity increases sharply. Therefore, the charge on the surface decreases rapidly, suppressing the generation of overvoltage. Compared with EP-SiC, its charge dissipation rate is significantly improved. Furthermore, the charge dissipation behavior is consistent with the relative magnitude of conductivity. Within the same timeframe, EP-SiC accumulates more surface charge compared to EP-Ag40 / SiC. These results indicate that EP-Ag40 / SiC, with its significant nonlinear conductivity, tends to dissipate charge more quickly when exposed to electrostatic hazards, thereby reducing the likelihood of electronic component failure.

Claims

1. A nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers, characterized in that, The composite material is composed of an epoxy resin matrix and a metal nanoparticle-silicon carbide composite filler; the metal nanoparticle-silicon carbide composite filler consists of silicon carbide particles and metal nanoparticles prepared by solution reduction.

2. The nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers according to claim 1, characterized in that, The volume fraction of silicon carbide is 20-25 vol, and the volume fraction of metal nanoparticles is 0.2-0.6 vol; the particle size of silicon carbide particles in the nonlinear conductive epoxy resin composite material constructed based on metal nanoparticles and silicon carbide particle fillers is in the range of 4-7 micrometers, and the particle size of metal nanoparticles is in the range of 8-60 nanometers.

3. The method for preparing the nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers as described in any one of claims 1-2, characterized in that, Includes the following steps: Metal nanoparticle-silicon carbide composite filler is mixed in a mixture of epoxy resin monomer, curing agent and accelerator, and after degassing and curing, a nonlinear conductive epoxy resin composite material based on metal nanoparticle and silicon carbide particle filler is obtained. The proportions of epoxy resin monomer, curing agent, accelerator, and metal nanoparticle-silicon carbide composite filler are as follows: 1 part epoxy resin monomer, 1-1.2 parts curing agent, 0.006-0.01 parts accelerator, and 8.2-10.28 parts metal nanoparticle-silicon carbide composite filler. The volume fraction of the metal nanoparticle-silicon carbide composite filler in the prepared composite material is 20%-25%.

4. The preparation method according to claim 3, characterized in that, The epoxy resin is at least one of alicyclic epoxy resin and bisphenol A type epoxy resin; the curing agent is methylhexahydrophthalic anhydride; and the accelerator is 2-ethyl-4-methylimidazole.

5. The preparation method according to claim 3, characterized in that, The curing conditions are as follows: first, cure at 95℃-115℃ for 40-80 minutes, then cure at 115℃-125℃ for 100-150 minutes, and then cure at 135℃-145℃ for 30-60 minutes.

6. The method for preparing the nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers according to claim 3, characterized in that, Metal nanoparticle-silicon carbide composite filler was prepared by the following method: 1) First, silicon carbide particles are mixed in deionized water and dispersed by ultrasonication to obtain a silicon carbide dispersion, wherein the mass fraction of silicon carbide is 0.047-0.141 wt%. Silver nitrate or gold chlorate powder is added and stirred to obtain a silicon carbide-metal salt mixed solution, which is allowed to stand for 15-60 minutes. The mass ratio of silver nitrate to silicon carbide in the mixed solution is 0.034-0.102, and the mass ratio of gold chlorate to silicon carbide is 0.068-0.

204. 2) The reaction solution was filtered and the solid was freeze-dried to obtain a composite filler with metal nanoparticles and silicon carbide particles in contact. 3) The composite filler obtained after freeze-drying, which has metal nanoparticles and silicon carbide particles in contact, is subjected to high-temperature treatment for 2-4 hours at a temperature of 300-360°C to obtain a metal nanoparticle-silicon carbide composite filler in which the metal nanoparticles and silicon carbide particles are in close contact.

7. The method for preparing the nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers according to claim 6, characterized in that, Step 3) is carried out under a nitrogen atmosphere.

8. The method for preparing the nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers according to claim 6, characterized in that, The particle size of the obtained metal nanoparticles is controlled by the static reaction time of the silicon carbide-metal salt mixed solution, and the particle size of the metal nanoparticles is in the range of 8-60 nanometers.

9. The application of a nonlinear conductive epoxy resin composite material based on metal nanoparticles and silicon carbide particle fillers as described in claim 1 or 2 in the preparation of electronic device packaging materials and insulation for high-voltage DC electrical equipment.

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