A modified tungsten carbide powder capable of inhibiting oxidation, and its preparation method and application

Abstract

The invention discloses a modified tungsten carbide powder capable of inhibiting oxidation, its preparation method and application, and is specifically related to the technical field of modified tungsten carbide powder preparation. The modified tungsten carbide powder includes a tungsten carbide powder matrix with a particle size of 1-30 μm, and its surface is coated with a composite layer consisting of stearic acid and polyaniline in a mass ratio of 0.5-2:1, combined by esterification and π-π conjugation, and a coating thickness of 50-200 nm. The preparation method is as follows: stearic acid and polyaniline are dissolved in acetone to form a solution with a total concentration of 1.5-3wt%, mixed with tungsten carbide powder, stirred at 45-55 ° C for 40-45 min under an inert atmosphere, filtered, washed with acetone and deionized water, and vacuum dried to obtain. The modified tungsten carbide powder can be used to prepare electronic components, such as integrated circuit packaging materials and power semiconductor heat dissipation substrates, and can effectively inhibit oxidation, ensure conductive effect, and improve component reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of modified tungsten carbide powder preparation, and more particularly to modified tungsten carbide powder capable of inhibiting oxidation, and a preparation method and application thereof. Background Art

[0002] Tungsten carbide (WC) is a ceramic material with excellent physical and chemical properties. Its melting point reaches 2870°C, its hardness approaches that of diamond, its thermal conductivity reaches 170-220 W / (m·K), and it exhibits excellent wear resistance and chemical stability. Due to its unique combination of properties, tungsten carbide powder is widely used in aerospace, machining, electronic packaging, and other fields. In the electronic component field, especially in integrated circuit packaging materials and power semiconductor heat dissipation substrates operating in high-temperature and high-humidity environments, tungsten carbide powder is an ideal filler due to its high thermal conductivity and mechanical strength.

[0003] Although tungsten carbide powder has excellent performance, it is prone to oxidation reaction in high temperature and high humidity environment, generating oxides such as WO3, which causes the material resistivity to increase sharply and the mechanical properties to decrease, seriously affecting the reliability of electronic components.

[0004] In the existing technology, the modification of tungsten carbide powder is mainly achieved by coating with a single organic substance or simply physically mixing, but there are obvious shortcomings:

[0005] When coated with single stearic acid, it is only combined with the surface of tungsten carbide through physical adsorption or weak chemical bonds. It is easy to crack and fall off in a hot and humid environment, and its antioxidant effect is limited.

[0006] Moreover, traditional coatings only rely on physical barriers and lack a blocking mechanism for electrochemical oxidation pathways, making them unable to inhibit oxidation for a long time in high temperature and high humidity environments.

[0007] Therefore, a modified tungsten carbide powder capable of inhibiting oxidation, a preparation method thereof, and an application thereof are proposed. Summary of the Invention

[0008] In order to overcome the above-mentioned defects of the prior art, the present invention provides a modified tungsten carbide powder capable of inhibiting oxidation, and a preparation method and application thereof, to solve the problems raised in the above-mentioned background technology.

[0009] To achieve the above object, the present invention provides the following technical solution: a modified tungsten carbide powder capable of inhibiting oxidation, comprising:

[0010] Tungsten carbide powder matrix, particle size 1-30μm;

[0011] A composite coating layer coated on the surface of the tungsten carbide powder matrix, wherein the composite coating layer is an inner layer formed by stearic acid first coated on the surface of the tungsten carbide powder, and an outer layer formed by polyaniline coated on the outer side of the inner layer, wherein the mass ratio of stearic acid to polyaniline is (0.5-2):1;

[0012] The composite coating layer is combined with the tungsten carbide powder matrix through esterification reaction and π-π conjugation, and the coating layer has a thickness of 50-200 nm.

[0013] The carboxyl groups of stearic acid form hydrogen bonds with the amino groups of polyaniline, enhancing the stability of the coating layer. At the same time, the hydrophobic chains cooperate to block water molecules. At the same time, polyaniline forms a dense network through π-π conjugation and is located in the outer layer of stearic acid, blocking the electron transfer path and inhibiting electrochemical oxidation. The thickness of the coating layer is between 50-200nm, thus avoiding being too thin and easy to break, and being too thick and reducing thermal conductivity.

[0014] Preferably, the tungsten carbide powder matrix is ​​prepared by mechanical alloying, direct reduction carbonization or sol-gel method.

[0015] The specific steps of preparing tungsten carbide powder matrix by mechanical alloying are as follows:

[0016] Tungsten powder with a purity of 99.9% and a particle size of 1-5 μm is mixed with carbon black with a purity of 99.5% and a particle size less than 50 nm in an atomic ratio of W:C=1:0.5.

[0017] Then a planetary ball mill was used with a rotation speed of 350 rpm and a ball-to-material ratio of 10:1 (carbide grinding balls).

[0018] Argon protection was used during the ball milling process, the ball milling time was 20 h, and cooling was paused every 30 min;

[0019] Then, the carbonization was carried out in situ at 1400°C under flowing argon and an oxygen content of <5 ppm for 2 h.

[0020] Finally, the powder was pulverized by air flow and sieved to 1-30 μm to prepare tungsten carbide powder.

[0021] The specific steps of preparing tungsten carbide powder matrix by direct reduction carbonization are as follows:

[0022] First, the precursor is prepared: ammonium metatungstate (AMT) and sucrose are dissolved in water at a molar ratio of W:C = 1:1.2, and spray-dried into a precursor powder with a particle size of 10-50μm;

[0023] Then, reduction carbonization is carried out, specifically, the temperature is increased from 20°C to 800°C at a heating rate of 5°C / min, and after reduction with hydrogen, the temperature is increased from 800°C to 1500°C at a heating rate of 10°C / min, and reduction is carried out with a CH4 / H2 mixed gas with a CH4 volume ratio of 20%, and the temperature is kept at 1500°C for 1 hour;

[0024] Then, the reduced carbonized product after being kept at this temperature for 1 hour was cooled to room temperature by passing argon gas at a cooling rate of 50°C / s to suppress grain growth;

[0025] Finally, the product after rapid cooling is subjected to air flow classification to screen out tungsten carbide powder with a particle size of 1-30 μm.

[0026] The reaction mechanism of preparing tungsten carbide powder matrix by direct reduction carbonization is:

[0027]

[0028] The specific steps of preparing tungsten carbide powder matrix by sol-gel method are as follows:

[0029] Sol preparation:

[0030] Tungsten source: ammonium metatungstate (0.5M) + citric acid (chelating agent, tungsten and citric acid in a molar ratio of W:CA=1:2);

[0031] Carbon source: phenolic resin (tungsten and carbon in a molar ratio of W:C=1:1);

[0032] Mix and stir at 60°C for 24 hours until a transparent sol is obtained, and the pH is controlled within the range of 3-4;

[0033] The stirred transparent sol was evaporated and dehydrated at 80°C, and then aged at 120°C for 48h to form a porous gel;

[0034] The porous gel was pre-carbonized at 300°C for 2 h, and then carbonized at 1000°C for 1 h under the protection of N2 atmosphere.

[0035] Then, the nano-WC powder was obtained by reduction at a H2 flow rate of 100 mL / min and a temperature of 1200 °C for 1.5 h;

[0036] Finally, the obtained nano-WC powder is subjected to ball milling to deagglomerate, and then sieved to 20-100nm, and finally agglomerated into 1-30μm particles to prepare tungsten carbide powder;

[0037] Preferably, in the composite coating layer, the mass ratio of stearic acid to polyaniline is 1:1.

[0038] A method for preparing modified tungsten carbide powder capable of inhibiting oxidation comprises the following steps:

[0039] Step 1: mixing stearic acid, polyaniline and a solvent to form a composite coating solution;

[0040] The solvent is acetone, and the total concentration of stearic acid and polyaniline is 1.5-3wt%;

[0041] Step 2: Mix tungsten carbide powder and composite coating solution in a mass ratio of 0.5:1–1:1, and stir at 300-400 r / min at 45-55°C for 40-45 minutes under inert atmosphere;

[0042] Step 3: After filtration, wash with acetone and deionized water in sequence;

[0043] Step 4: Vacuum dry at 50-60°C for 1.5-2 hours.

[0044] Preferably, in step 1, the order of adding stearic acid and polyaniline is:

[0045] First dissolve stearic acid in acetone, then add polyaniline and stir until completely dispersed.

[0046] Preferably, in step 1, stearic acid is dissolved in acetone and stirred for 0-10 minutes, and then polyaniline is added and stirred for 10-35 minutes.

[0047] Stearic acid (SA) is first dissolved in acetone to form a homogeneous solution. At this point, the stearic acid molecules exist in a free state with the carboxyl groups exposed. Polyaniline (PANI) is then added, which is dispersed in the solution and has no strong interaction with the stearic acid molecules. When WC powder is added to the composite solution, stearic acid is rapidly adsorbed due to the strong affinity between the carboxyl groups and the WC surface, forming the first layer of coating, with the hydrocarbon groups facing outward to form a hydrophobic interface.

[0048] Subsequently, the polyaniline dispersed in the solution is attached to the stearic acid outer layer under stirring in the following manner:

[0049] Van der Waals forces between hydrophobic hydrocarbon groups and polyaniline segments;

[0050] The stirring shear force causes polyaniline to wrap around the surface of the stearic acid layer, forming a WC core-stearic acid-polyaniline shell structure from the inside out;

[0051] The carboxyl group (-COOH) of SA and the W-OH hydroxyl group on the WC surface can form a strong covalent bond with an esterification reaction, with a bond energy of approximately 250-350 kJ / mol. The benzene ring of PANI and WC are primarily bound by a weaker π-π stacking interaction. At a reaction temperature of 45-55°C, SA thermodynamically prioritizes occupying the active sites on the WC surface. Although SA and PANI molecules are evenly dispersed in the premixed solution, after the addition of WC powder, SA, with its small molecular weight and rapid diffusion rate, will first contact the WC surface. Due to the entanglement effect, the PANI macromolecules require more than 15 minutes to effectively diffuse to the interface. Therefore, when tungsten carbide powder is added to the prepared composite coating solution, it is ensured that after stearic acid anchors the tungsten carbide surface, polyaniline self-assembles into a continuous film through π-π stacking. During this process, inert gas protection is used to prevent the polyaniline from oxidative inactivation.

[0052] The coated modified tungsten carbide powder is first cleaned with acetone. The main reasons for using acetone for cleaning are:

[0053] During the coating process, some stearic acid and polyaniline may not be adsorbed on the tungsten carbide surface and still exist in the filter cake in a free state. Acetone is the solvent of step 1 and has good solubility for both. It can effectively dissolve and wash away unbound organic matter to avoid impurity residues affecting the coating effect.

[0054] Polyaniline may form localized aggregates in the solution, which may not be uniformly coated on the tungsten carbide surface. Acetone can penetrate and disperse these aggregates, washing away the unbound polyaniline and ensuring a uniform coating.

[0055] The mother liquor remaining in the filter cake after filtration contains acetone, unreacted organic matter, and possible by-products, such as oxidation products of stearic acid or polyaniline. Washing with acetone can displace the mother liquor and reduce the residual impurities during subsequent drying.

[0056] Then, deionized water is used for washing. After cleaning with acetone, deionized water is still needed for washing because:

[0057] Acetone is volatile but may remain in the filter cake. Deionized water can dilute and wash away the acetone, preventing it from affecting product quality during the subsequent drying process, such as forming pores or residual odor.

[0058] If metal ions are introduced into the raw materials or during the reaction, such as W produced by the dissolution of metal oxides on the surface of WC powder, n+ 2. Trace metal salts in the solution: deionized water can reduce the ion concentration through multiple washings to prevent it from affecting the stability of the coating layer or subsequent application performance;

[0059] Stearic acid and polyaniline have extremely low solubility in water. Deionized water washing can promote the further solidification of the two on the surface of tungsten carbide, enhance the bonding strength between the coating layer and the substrate, thereby allowing stearic acid to form a more compact arrangement structure in water, and the hydrophobic chain segments of polyaniline can be further wrapped around the outer layer of stearic acid;

[0060] If acetone and ionic impurities remain in the filter cake, they may migrate to the particle surface with the solvent during vacuum drying (50-60°C), causing surface contamination or defects. Washing with deionized water can reduce this risk.

[0061] After washing, the powder is vacuum dried at 50-60° C. for 1.5-2 hours to obtain a purer modified tungsten carbide powder.

[0062] The invention discloses an application of modified tungsten carbide powder capable of inhibiting oxidation in the preparation of electronic components for use in a high-temperature and high-humidity environment, wherein the electronic components have a working environment with a humidity of ≥80% and a temperature of ≥100°C.

[0063] Preferably, the electronic component is an integrated circuit packaging material or a power semiconductor heat dissipation substrate.

[0064] Technical effects and advantages of the present invention:

[0065] 1. The composite coating formed by stearic acid and polyaniline is combined with the tungsten carbide powder matrix through esterification reaction and π-π conjugation to construct a dense antioxidant barrier, effectively blocking the penetration of oxygen and water molecules.

[0066] 2. The carboxyl group of stearic acid forms a strong covalent bond with the surface of tungsten carbide, serving as the inner layer anchoring matrix; polyaniline forms a continuous network on the outer layer through π-π stacking. When the mass ratio of stearic acid and polyaniline is 1:1, the coating thickness is 50-200nm, which can avoid cracking due to being too thin and prevent the thermal conductivity from being reduced due to being too thick. When preparing the coating solution, stearic acid is first added to dissolve in acetone, and then polyaniline is added. This can ensure that stearic acid is preferentially combined with tungsten carbide powder, which can not only improve the density of the coating layer, shorten the raw material compounding process, avoid interface mixing, but also improve processing efficiency.

[0067] 3. The tungsten carbide powder matrix can be prepared by mechanical alloying, direct reduction carbonization or sol-gel method to adapt to different process requirements. In electronic components in high temperature and high humidity environments such as integrated circuit packaging materials and power semiconductor heat dissipation substrates, the modified tungsten carbide powder has good oxidation resistance and thermal conductivity, meeting the reliability requirements of high-end electronic devices. DETAILED DESCRIPTION

[0068] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0069] Example 1

[0070] The modified tungsten carbide powder capable of inhibiting oxidation provided in Example 1 includes the following raw materials:

[0071] 100 parts of tungsten carbide powder prepared by direct reduction carbonization method, with a particle size of 15±3 μm; 0.75 parts of stearic acid; 0.75 parts of polyaniline; and 100 parts of acetone.

[0072] The preparation steps of modified tungsten carbide powder capable of inhibiting oxidation are as follows:

[0073] Stearic acid was added to acetone and stirred at 50°C for 10 min to completely dissolve the stearic acid to obtain solution A.

[0074] Then, polyaniline was added to solution A and stirred for 20 min until a blue uniform dispersion was obtained to obtain solution B;

[0075] Add tungsten carbide powder into solution B, stir at 50°C and 350 rpm for 45 min under nitrogen protection to obtain mixed solution C;

[0076] The mixed solution C was filtered, washed once with acetone, and then washed twice with deionized water. Subsequently, it was vacuum dried at 55° C. for 1.5 h to obtain modified tungsten carbide powder.

[0077] Example 2

[0078] The modified tungsten carbide powder capable of inhibiting oxidation provided in Example 2 includes the following raw materials:

[0079] 100 parts of tungsten carbide powder prepared by direct reduction carbonization method, with a particle size of 15±3 μm; 0.5 parts of stearic acid; 1.0 parts of polyaniline; and 100 parts of acetone.

[0080] The preparation steps of modified tungsten carbide powder capable of inhibiting oxidation are as follows:

[0081] Stearic acid was added to acetone and stirred at 50°C for 10 min to completely dissolve the stearic acid to obtain solution A.

[0082] Then, polyaniline was added to solution A and stirred for 20 min until a blue uniform dispersion was obtained to obtain solution B;

[0083] Add tungsten carbide powder into solution B, stir at 50°C and 350 rpm for 45 min under nitrogen protection to obtain mixed solution C;

[0084] The mixed solution C was filtered, washed once with acetone, and then washed twice with deionized water. Subsequently, it was vacuum dried at 55° C. for 1.5 h to obtain modified tungsten carbide powder.

[0085] Example 3

[0086] The modified tungsten carbide powder capable of inhibiting oxidation provided in Example 3 includes the following raw materials:

[0087] 100 parts of tungsten carbide powder prepared by a sol-gel method, with a particle size of 15±3 μm; 1.0 part of stearic acid; 1.0 part of polyaniline; and 100 parts of acetone.

[0088] The preparation steps of modified tungsten carbide powder capable of inhibiting oxidation are as follows:

[0089] Stearic acid was added to acetone and stirred at 50°C for 10 min to completely dissolve the stearic acid to obtain solution A.

[0090] Then, polyaniline was added to solution A and stirred for 20 min until a blue uniform dispersion was obtained to obtain solution B;

[0091] Add tungsten carbide powder into solution B, stir at 50°C and 350 rpm for 45 min under nitrogen protection to obtain mixed solution C;

[0092] The mixed solution C was filtered, washed once with acetone, and then washed twice with deionized water. Subsequently, it was vacuum dried at 55° C. for 1.5 h to obtain modified tungsten carbide powder.

[0093] Example 4

[0094] The modified tungsten carbide powder capable of inhibiting oxidation provided in Example 4 includes the following raw materials:

[0095] 100 parts of tungsten carbide powder prepared by mechanical alloying method, with a particle size of 15±3 μm; 0.75 parts of stearic acid; 0.75 parts of polyaniline; and 100 parts of acetone.

[0096] The preparation steps of modified tungsten carbide powder capable of inhibiting oxidation are as follows:

[0097] Stearic acid was added to acetone and stirred at 50°C for 10 min to completely dissolve the stearic acid to obtain solution A.

[0098] Then, polyaniline was added to solution A and stirred for 20 min until a blue uniform dispersion was obtained to obtain solution B;

[0099] Add tungsten carbide powder into solution B, stir at 50°C and 350 rpm for 45 min under nitrogen protection to obtain mixed solution C;

[0100] The mixed solution C was filtered, washed once with acetone, and then washed twice with deionized water. Subsequently, it was vacuum dried at 55° C. for 1.5 h to obtain modified tungsten carbide powder.

[0101] Comparative Example 1

[0102] The modified tungsten carbide powder capable of inhibiting oxidation provided in Comparative Example 1 includes the following raw materials:

[0103] 100 parts of tungsten carbide powder prepared by direct reduction carbonization method, with a particle size of 15±3 μm; 1.5 parts of stearic acid; and 100 parts of acetone.

[0104] The preparation steps of modified tungsten carbide powder capable of inhibiting oxidation are as follows:

[0105] Stearic acid was added to acetone and stirred at 50°C for 10 min to completely dissolve the stearic acid to obtain solution A.

[0106] Add tungsten carbide powder into solution A, stir at 50°C and 350 rpm for 45 minutes to obtain mixed solution D.

[0107] The mixed solution D was filtered, washed once with acetone, and then washed twice with deionized water. Subsequently, it was vacuum dried at 55° C. for 1.5 h to obtain modified tungsten carbide powder.

[0108] Comparative Example 2

[0109] The modified tungsten carbide powder capable of inhibiting oxidation provided in Comparative Example 2 includes the following raw materials:

[0110] 100 parts of tungsten carbide powder prepared by direct reduction carbonization method, with a particle size of 15±3 μm; 0.75 parts of stearic acid; 0.75 parts of polyaniline; and 100 parts of acetone.

[0111] The preparation steps of modified tungsten carbide powder capable of inhibiting oxidation are as follows:

[0112] Stearic acid and polyaniline were added to acetone simultaneously and stirred at 50°C for 30 min until a blue uniform dispersion was obtained to obtain a first solution;

[0113] Add tungsten carbide powder to the first solution, and stir at 50°C and 350 rpm for 45 minutes under nitrogen protection to obtain a mixed solution;

[0114] The mixed liquid was filtered, washed once with acetone, and then washed twice with deionized water. Subsequently, it was vacuum dried at 55° C. for 1.5 h to obtain modified tungsten carbide powder.

[0115] Comparative Example 3

[0116] This comparative example 3 provides 100 parts of untreated tungsten carbide powder prepared by direct reduction carbonization method.

[0117] Oxidation experiment

[0118] The modified tungsten carbide powders prepared in Examples 1-4 and Comparative Examples 1-2 and the tungsten carbide powder in Comparative Example 3 were placed in a constant temperature and humidity chamber under double 85 conditions for accelerated oxidation, and the resistivity was detected every 5 days, where the double 85 conditions were a temperature of 85°C and a humidity of 85%.

[0119] Evaluation indicators:

[0120] Oxidation slope a value: y=ax+b, where y is the resistance value, x represents the oxidation time, a is the slope, reflecting the oxidation rate, and b is the intercept, representing the initial state resistance;

[0121] 25-day resistance growth rate = (R 25 -R0) / R0×100%;

[0122] The experimental results are shown in Table 1 below.

[0123] Table 1: Oxidation data of Examples 1-4 and Comparative Examples 1-3

[0124]

[0125] As can be seen from Table 1 above, the resistance growth rate of SA:PANI=1:1 in Example 1 is 141%, which is much lower than 178% of the single-component optimal comparative example 1.

[0126] In Comparative Example 2, the materials were added simultaneously. Due to the competitive binding of SA / PANI, the a value increased to 0.63, which was 21% higher than that in Example 1. It can be seen that the preferential binding of stearic acid with tungsten carbide powder was significantly better than the simultaneous binding, avoiding the binding hindrance of polyaniline to stearic acid, and the coating state after binding was more compact, which improved the binding strength. In Comparative Example 1, in which no polyaniline was added, the coating state had obviously weaker binding strength and poorer density.

[0127] The tungsten carbide powder matrix prepared by direct reduction carbonization in Example 1 has the best effect and is more conducive to providing a dense surface, allowing stearic acid to be anchored.

[0128] In Example 2, the addition of stearic acid was reduced, resulting in a resistance growth rate of 171%, confirming that insufficient stearic acid resulted in weakened interfacial bonding.

[0129] In Comparative Example 1, only stearic acid was added without polyaniline, which resulted in large-scale cracking of the coating layer due to the lack of polyaniline network support. Therefore, it can be seen that the addition of polyaniline can significantly improve the density of the coating layer.

[0130] Specifically, in Comparative Example 1, in which only stearic acid was added, the oxidation slope a value was 0.68, the resistance growth rate after 25 days was 178%, and the coating state was "cracked and peeled (30% area)".

[0131] In Example 1 in which polyaniline was added, the oxidation slope a value dropped to 0.52, the resistance growth rate dropped to 141%, and the coating layer was "dense and continuous without cracks."

[0132] Comparing the two, it can be seen that the antioxidant capacity of the coating is significantly improved after adding polyaniline. The core premise of antioxidant capacity is the density of the coating - only a dense structure can effectively block oxygen, water molecules and electron transfer paths. This is the direct experimental basis for the conclusion.

[0133] Secondly, in Comparative Example 1, since no polyaniline was added and the coating consisted solely of stearic acid, cracking and flaking were observed. In contrast, in Examples 1-4, after adding polyaniline, the coatings all appeared dense and continuous, with no cracks or only minor defects (for example, in Example 4, the microcrack area was less than 5%). This difference in macroscopic properties directly reflects the contribution of polyaniline to the integrity of the coating, and integrity is a key indicator of density.

[0134] Furthermore, when stearic acid is coated alone, its bonding with the tungsten carbide matrix mainly relies on physical adsorption or weak chemical bonds, and the interaction between stearic acid molecular chains is relatively weak. In dry and subsequent high-temperature and high-humidity environments, the stearic acid layer is prone to cracking due to stress shrinkage. This cracking directly destroys the continuity of the coating layer, causing oxygen and water molecules to penetrate into the matrix through the cracks, accelerating oxidation. At this time, "cracking" means that the coating layer has a large number of pores and fractures, that is, the density is lost.

[0135] The addition of polyaniline improves density and avoids cracking through the following mechanisms:

[0136] The polyaniline molecular chains form a rigid network through π-π conjugation, which is coated on the outer layer of stearic acid. It acts like a "skeleton" to enhance the mechanical strength of the coating layer and inhibit cracking of the stearic acid layer caused by stress shrinkage.

[0137] The carboxyl group of stearic acid forms hydrogen bonds with the amino group of polyaniline, making the two-layer structure tightly combined and reducing the gap between the layers; at the same time, the hydrophobic chain segments of polyaniline and the hydrophobic chains of stearic acid work synergistically to further block the penetration of water molecules and avoid swelling and cracking of the coating layer due to water erosion.

[0138] The entangled structure of the polyaniline network can fill the tiny pores that may be produced by the stearic acid layer, thereby improving the overall density at the microscopic level.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 modified tungsten carbide powder capable of inhibiting oxidation, characterized in that: include: Tungsten carbide powder matrix, particle size 1-30μm; A composite coating layer coated on the surface of the tungsten carbide powder matrix, wherein the composite coating layer is an inner layer formed by stearic acid first coated on the surface of the tungsten carbide powder, and an outer layer formed by polyaniline coated on the outer side of the inner layer, wherein the mass ratio of stearic acid to polyaniline is (0.5-2):1; The thickness of the composite coating layer is 50-200 nm; The steps for preparing the modified tungsten carbide powder capable of inhibiting oxidation include: Step 1: mixing stearic acid, polyaniline and a solvent to form a composite coating solution; The solvent is acetone, and the total concentration of stearic acid and polyaniline is 1.5-3wt%; Step 2: Mix tungsten carbide powder and composite coating solution in a mass ratio of 0.5:1–1:1, and stir at 300-400 r / min at 45-55°C for 40-45 minutes under inert atmosphere; Step 3: After filtration, wash with acetone and deionized water in sequence; Step 4: vacuum drying at 50-60°C for 1.5-2 hours; Wherein, in step 1, the order of adding stearic acid and polyaniline is: First dissolve stearic acid in acetone and stir for 0-10 minutes, then add polyaniline and stir for 10-35 minutes to completely disperse it.

2. The modified tungsten carbide powder capable of inhibiting oxidation according to claim 1, characterized in that: The tungsten carbide powder matrix is ​​prepared by mechanical alloying, direct reduction carbonization or sol-gel method.

3. The modified tungsten carbide powder capable of inhibiting oxidation according to claim 1, characterized in that: In the composite coating layer, the mass ratio of stearic acid to polyaniline is 1:

1.

4. Use of the modified tungsten carbide powder capable of inhibiting oxidation according to any one of claims 1 to 3 in the preparation of electronic components for use in high temperature and high humidity environments, characterized in that: The electronic components work in an environment with a humidity ≥ 80% and a temperature ≥ 100°C.

5. The use of the modified tungsten carbide powder capable of inhibiting oxidation according to claim 4 in the preparation of electronic components for high temperature and high humidity environments, characterized in that: The electronic component is an integrated circuit packaging material or a power semiconductor heat dissipation substrate.

Images