CN-121990827-A - Preparation method of high-pressure-resistance high-strength graphite reinforced electrode paste

CN121990827ACN 121990827 ACN121990827 ACN 121990827ACN-121990827-A

Abstract

The invention relates to the technical field of electrode paste, in particular to a preparation method of high-pressure-resistance high-strength graphite reinforced electrode paste, which comprises the steps of sequentially carrying out oxidation modification and silane modification on crystalline flake graphite powder, preparing silane modified graphite powder, synchronously preparing boron-nitrogen source precursors, coating amino carbon quantum dots with silicon to obtain silicon coated carbon quantum dots, preparing a composite binder, tungsten carbide-aluminum nitride composite reinforced phase and carbon-coated silicon powder, blending and kneading components such as silane modified graphite powder, boron-nitrogen source precursors and the like, pressing the mixture under gradient pressure to obtain a blank, and carrying out sectional roasting and cooling on the blank to obtain the target electrode paste. According to the invention, interface compatibility is optimized through oxidation-silane modification of crystalline flake graphite, a silicon-coated carbon quantum dot reinforced bonding system is adopted, a mechanical support network is constructed by a composite reinforced phase, boron-nitrogen source in-situ doping is supplemented and reinforced, and the compact structure is ensured by combining gradient pressure pressing and sectional roasting. The pressure-resistant strength at normal temperature, the mechanical stability at high temperature and the compactness of the electrode paste are improved under the synergistic effect of all links, and the high-temperature high-load working condition can be stably adapted.

Inventors

LU XUSHAN
ZHANG YUSHENG
YANG GUOJUN
DA CHAOYING
WU XUEGANG
YAO YIN

Assignees

乌海阳光炭素有限公司

Dates

Publication Date: 20260508
Application Date: 20260209

Claims (10)

1. The preparation method of the high-pressure-resistance high-strength graphite reinforced electrode paste is characterized by comprising the following steps of: Step 1, adding flake graphite powder into a mixed solution of a nitric acid solution and a potassium permanganate solution for mixing reaction, washing and drying to obtain oxidized modified graphite powder, dispersing the oxidized modified graphite powder into an ethanol solution, adding gamma-aminopropyl triethoxysilane for stirring reaction, filtering and drying to obtain silane modified graphite powder, mixing borax with urea, adding deionized water for ultrasonic dissolution to obtain a boron-nitrogen source precursor solution; Dispersing the aminated carbon quantum dots in a mixed solvent of absolute ethyl alcohol and deionized water, dropwise adding ammonia water to adjust the pH of the system, slowly dropwise adding an absolute ethyl alcohol solution of tetraethoxysilane, continuously stirring for reaction, and centrifuging, washing and drying after the reaction is finished to obtain the silicon-coated carbon quantum dots; Adding phenolic resin into polyimide resin for melting, mixing and stirring with the silicon-coated carbon quantum dots and the titanate coupling agent to obtain a composite adhesive, mixing and ball-milling tungsten carbide nano particles and aluminum nitride powder to obtain a composite reinforcing phase, dispersing silicon powder into formaldehyde solution, adjusting pH, and stirring for reaction to obtain carbon-plated silicon powder; Step 4, after blending and kneading the silane modified graphite powder, the boron-nitrogen source precursor solution and the composite adhesive, adding the composite reinforcing phase and the carbon-plated silicon powder, curing, adding the carbon nano tube, mixing and stirring to obtain electrode paste slurry, pressing the electrode paste slurry under gradient pressure, molding, and demolding to obtain an electrode paste blank; And 5, placing the electrode paste blank body in inert atmosphere for sectional roasting treatment, and cooling to obtain the high-pressure-resistance high-strength graphite reinforced electrode paste.
2. The preparation method of the high-pressure-resistance high-strength graphite-reinforced electrode paste according to claim 1, wherein in the step 1, the mass ratio of the flake graphite powder to the nitric acid solution to the potassium permanganate solution is 1 (3-5): (0.1-0.3), the concentration of the nitric acid solution is 10-30 wt%, the concentration of the potassium permanganate solution is 0.5-2 wt%, the mass ratio of the oxidation-modified graphite powder to the ethanol solution to the gamma-aminopropyl triethoxysilane is 1 (5-15): (0.01-0.05), the concentration of the ethanol solution is 35-55 wt%, and the mass ratio of the borax to the urea to the deionized water is 1 (1.5-3): (8-45).
3. The method for preparing the high-pressure-resistant high-strength graphite-reinforced electrode paste according to claim 1, wherein in the step 1, the temperature of the mixing reaction is 15-40 ℃ and the time is 3-8 hours, the washing is performed until the pH is 6.5-7.5, the temperature of the stirring reaction is 40-70 ℃ and the time is 2-6 hours, and the ultrasonic power of ultrasonic dissolution is 100-300W and the time is 60-90 minutes.
4. The preparation method of the high-pressure-resistance high-strength graphite-reinforced electrode paste according to claim 1, wherein in the step 2, the pH value is 9-11, the mass ratio of the amino carbon quantum dots, the mixed solvent, the ammonia water and the ethyl orthosilicate is1 (100-200): (1-5): (5-20), the mass ratio of the ethyl orthosilicate to the absolute ethyl alcohol is1 (1-2), and the volume ratio of the absolute ethyl alcohol to the deionized water in the mixed solvent is 4-9): 1.
5. The method for preparing a high pressure-resistant and high strength graphite reinforced electrode paste according to claim 1, wherein in the step 2, the dispersing temperature is 30-50 ℃ and the dispersing time is 30-60min, and the stirring reaction temperature is 40-70 ℃ and the stirring reaction time is 2-6h.
6. The preparation method of the high-pressure-resistance high-strength graphite-reinforced electrode paste according to claim 1, wherein in the step 3, the mass ratio of phenolic resin to polyimide resin to silicon-coated carbon quantum dots to titanate coupling agent is (6-8): (2-4): (0.1-0.5): (0.1-0.5), the mass ratio of the tungsten carbide nano particles to aluminum nitride powder is (3-7): 1, the mass ratio of the silicon powder to formaldehyde solution is (1-3), and the mass fraction of the formaldehyde solution is 30-40 wt%.
7. The preparation method of the high-pressure-resistant high-strength graphite reinforced electrode paste according to claim 1, wherein in the step 3, the melting temperature is 120-160 ℃ and the time is 30-90min, the mixing and stirring temperature is 180-220 ℃ and the time is 20-60min, the ball-to-material ratio of the mixing ball mill is (5-10): 1, the rotating speed is 200-400rpm, the time is 2-6h, and the pH is 3.0-4.0.
8. The preparation method of the high-pressure-resistance high-strength graphite reinforced electrode paste according to claim 1, wherein in the step 4, the mass ratio of the silane modified graphite powder to the boron-nitrogen source precursor solution to the composite binder to the composite reinforcing phase to the carbon-plated silicon powder to the carbon nanotubes is 1 (0.1-0.3): (0.2-0.4): (0.05-0.15): (0.03-0.08): (0.01-0.05).
9. The method for preparing the high-pressure-resistance high-strength graphite-reinforced electrode paste according to claim 1, wherein in the step 4, the gradient pressure comprises a first gradient pre-pressing exhaust pressure and a second gradient main pressure densification pressure, wherein the first gradient pre-pressing exhaust pressure is 10-30MPa, the dwell time is 1-3min, the second gradient main pressure densification pressure is 50-100MPa, and the dwell time is 3-8min.
10. The method for preparing the high-pressure-resistant high-strength graphite-reinforced electrode paste according to claim 1, wherein in the step 5, the sectional baking treatment comprises a first-stage baking and a second-stage baking, wherein the temperature of the first-stage baking is 100-800 ℃, the heat preservation time is 4-8h, the temperature of the second-stage baking is 900-1200 ℃, and the heat preservation time is 4-8h.

Description

Preparation method of high-pressure-resistance high-strength graphite reinforced electrode paste Technical Field The application relates to the technical field of electrode paste, in particular to a preparation method of high-pressure-resistance high-strength graphite reinforced electrode paste. Background The graphite electrode paste is used as a key conductive and structural material in the high-temperature industrial fields of metallurgy, chemical industry and the like, and the pressure resistance and the mechanical strength of the graphite electrode paste directly determine the stability and the safety of industrial production. With the development of industrial devices to large-scale and high-efficiency, the performance requirements on the electrode paste are increasingly severe, and the use requirements of the traditional graphite electrode paste under the working conditions of high load and high temperature are difficult to meet. In the prior art, in order to improve the performance of the graphite electrode paste, means such as graphite surface modification, reinforcing phase addition, roasting process optimization and the like are often adopted. In the aspect of graphite modification, the conventional method is mostly single oxidation treatment or simple silane coupling agent modification, the oxidation treatment can only introduce a small amount of active functional groups on the surface of graphite, the subsequent silane grafting is mostly dependent on physical adsorption or weakening of chemical bond combination, a stable interface bridging structure cannot be formed, the interface bonding strength of graphite and an adhesive is low, interface stripping is easy to occur when the graphite is stressed, and the load transfer efficiency is poor. In the reinforcing phase design, the prior art mostly adopts a single-scale or single-type reinforcing phase, lacks multi-scale collaborative design, is easy to agglomerate in micron-scale reinforcing phase and can not fill micro pores, the nano-scale reinforcing phase is difficult to form a continuous supporting network, and the crack growth inhibition effect is limited. In the aspect of the roasting process, most of traditional processes are single-temperature roasting or simple sectional heating, so that efficient impurity removal, accurate cooperation of doping modification and densification are difficult to realize, a high-dispersity high-hardness reinforcing phase cannot be generated through in-situ reaction, the final porosity of the material is high, and the improvement of pressure resistance and mechanical strength is further restricted. Therefore, aiming at the bottleneck of the prior art, developing a graphite reinforced electrode paste preparation technology capable of constructing a stable interface structure and realizing multi-scale synergistic reinforcement becomes a technical problem to be solved in the current field. Disclosure of Invention Aiming at the problems, the application provides a preparation method of high-pressure-resistance high-strength graphite reinforced electrode paste, which realizes the improvement of the pressure resistance and mechanical strength of the electrode paste by a combination technology of stable interface construction by scale graphite oxidation-silane modification, optimized bonding performance of an amino carbon quantum dot silicon coating synergistic composite adhesive, multi-scale composite reinforced phase-synergistic reinforcement, boron-nitrogen source in-situ doping and boron carbide generation and gradient pressure pressing-two-stage roasting precise regulation and control. In order to achieve the above purpose, the application adopts the following technical scheme: The application provides a preparation method of high-pressure-resistance high-strength graphite reinforced electrode paste, which comprises the following steps: Step 1, adding flake graphite powder into a mixed solution of a nitric acid solution and a potassium permanganate solution for mixing reaction, washing and drying to obtain oxidized modified graphite powder, dispersing the oxidized modified graphite powder into an ethanol solution, adding gamma-aminopropyl triethoxysilane for stirring reaction, filtering and drying to obtain silane modified graphite powder, mixing borax with urea, adding deionized water for ultrasonic dissolution to obtain a boron-nitrogen source precursor solution; dispersing the aminated carbon quantum dots in a mixed solvent of absolute ethyl alcohol and deionized water, dropwise adding ammonia water to adjust the pH of the system to 9-11, slowly dropwise adding absolute ethyl alcohol solution of tetraethoxysilane, continuously stirring for reaction, and centrifuging, washing and drying after the reaction is finished to obtain the silicon-coated carbon quantum dots; Adding phenolic resin into polyimide resin for melting, mixing and stirring with the silicon-coated carbon quantum dots and the titanate coupling