CN116854474A - A highly wear-resistant resin-based carbon brush composite material and its preparation method - Google Patents

Abstract

The invention discloses a high wear-resistant resin-based carbon brush composite material and a preparation method thereof, wherein the high wear-resistant resin-based carbon brush composite material comprises the following components in parts by weight: 60-80% of electrochemical graphite powder, 20-40% of flake graphite powder, and 15-25% of adhesive by total weight of the electrochemical graphite powder and the flake graphite powder, and carrying out dry powder hot mixing on 60-80% of the fossil toner and 20-40% of the flake graphite powder at a temperature of 85-100 ℃ for 2-3 hours; after the temperature is reduced to 40-50 ℃, adding 15-25% of phenolic resin powder into the mixed powder obtained in the step S1; continuing kneading for 0.5-1 hr, adding 75-85% industrial liquor to the obtained mixed pasteHeating to 70-90deg.C, kneading for 1-2 hr; grinding and sieving the paste to obtain a first-stage material; 90-100% of the first-stage material and less than 10% of MoS after simple sphericization ₂ Carrying out secondary kneading at room temperature for 1-3h; and carrying out compression molding on the pressed powder of the secondary paste under 160-200MPa, and roasting to obtain the carbon brush composite material. The invention has the advantages of low cost, and the prepared carbon brush material has high density, high wear resistance and good stability.

Description

A highly wear-resistant resin-based carbon brush composite material and its preparation method

Technical field

The invention relates to the field of carbon graphite materials, and in particular to a highly wear-resistant resin-based carbon brush composite material and a preparation method thereof.

Background technique

Carbon brushes are also called electric brushes. As a kind of sliding contact, they are widely used in many electrical equipment. They are devices for transmitting energy or signals between the fixed part and the rotating part of a motor or generator or other rotating machinery. They are generally square in shape. , stuck on the metal bracket, with a spring inside to press it tightly on the rotating shaft. When the motor rotates, the electric energy is delivered to the coil through the phase commutator. This requires the carbon brush to have a certain mechanical strength and the ability to suppress spark generation. However, as the power requirements for various electrical appliances increase, the current density of the motor continues to increase, and the matching carbon brushes do not meet the requirements for wear resistance, homogeneity, etc., resulting in shortened service life and other problems. Therefore, it is necessary to develop a carbon brush material that is wear-resistant, has good electrical conductivity, and has a low spark level.

Carbon brushes are generally multi-carbon phase heterogeneous materials prepared from graphite, adhesives, and some reinforcing materials. Experts and scholars at home and abroad have done a lot of research in this area. For example, the invention patent CN201810384528.1 discloses a composite material preparation process for preparing electric brushes, using modified coal pitch, graphite powder, molybdenum disulfide, and vinyl vinyl groups. Bisstearamide, stearamide, coke powder, silver powder and copper powder are used as raw materials, and then mixed according to a certain proportion to prepare the base particles and raw materials for each working layer, which are hot-pressed under a protective atmosphere to prepare bulk brush materials, including The slip ring material has a simple preparation process and low cost, and its performance can meet the current market demand. The invention patent CN201910060343. Thermoplastic phenolic resin/furan resin, tungsten disulfide/cerium oxide are used as raw materials, and then mixed according to a certain proportion and then spheroidized, and then pressed and solidified to produce a spherical resin-based brush composite material. The brush material has a curing temperature of 180 and 210°C, a molded density of 1.65 and 1.58g/cm ³ , and an isotropy ratio of 1.67 and 1.20. With the continuous changes in usage conditions, higher requirements are also put forward for carbon brush materials.

Contents of the invention

The purpose of the present invention is to provide a highly wear-resistant resin-based carbon brush composite material and its preparation method. The prepared carbon brush material has high density, high wear resistance and good stability; by preparing the first-stage material and then carrying out the second stage After the first mixing and kneading, the carbon brush composite material obtained has a spherical structure, which not only has higher density and strength, but also has good wear resistance, and the preparation time is short, which saves costs.

In order to achieve the above object, the technical solution adopted by the present invention is: a highly wear-resistant resin-based carbon brush composite material includes the following components by weight: 60-80% electrochemical graphite powder and 20-40% flake graphite powder.

Furthermore, the binder also includes 15-25% of the total weight of electrochemical graphite powder and flake graphite powder.

Furthermore, a dispersant accounting for 75-85% of the total weight of electrochemical graphite powder and flake graphite powder is included.

Further, the binder is phenolic resin powder.

Further, the dispersant is industrial alcohol.

A method for preparing a highly wear-resistant resin-based carbon brush composite material, including the following steps:

S1. Hot mix 60-80% chemical graphite powder and 20-40% flake graphite powder with dry powder at a temperature of 85-100°C for 2-3 hours;

S2. After the temperature drops to 40-50°C, add 15-25% phenolic resin powder to the mixed powder obtained in step S1 and continue kneading;

S3. After continuing kneading for 0.5-1h, add 75-85% industrial alcohol to the mixed paste obtained in step S2, raise the temperature to 70-90°C, and continue kneading for 1-2h;

S4. Grind and sieve the paste in step S3 to obtain first-stage material;

S5. Knead 90-100% of the first-stage material in step S4 and less than 10% of MoS ₂ after simple spheroidization for a second time at room temperature. The kneading time is 1-3 hours;

S6. Mold the pressed powder of the secondary paste obtained in step S5 at 160-200MPa, and then freely heat it up at room temperature -70°C; at 70°C-190°C, the heating rate is 9°C/h , keep warm for 5 hours; when 190℃-360℃, the heating rate is 8℃/h, keep warm for 4h; when 360℃-460℃, the heating rate is 5℃/h, keep warm for 8h; when 460℃-950℃, The heating rate is 8°C/h, and the baking is performed under the heating curve of 6 hours of heat preservation. After processing, the carbon brush composite material is obtained.

Compared with the prior art, the advantages of the present invention are:

1. The carbon brush composite material of the present invention uses high-purity electrochemical graphite powder, which contains very few raw material impurities, improves the true specific gravity, and also has good oxidation resistance, thermal conductivity and chemical stability. Using an appropriate amount of phenolic resin will form resin coke during the roasting process, which can improve the strength and hardness of the product. MoS ₂ easily slides along the SS surface under the action of shear force, which can reduce friction; in addition, it is diamagnetic and can assist rectification and commutation under high temperature and high pressure. Each phase of the carbon brush composite material prepared by this method is evenly distributed, and the aggregate carbon phase and other phases are effectively combined. At the same time, it can also reduce the occurrence of micro-cracks in the material and improve the comprehensive mechanical properties of the composite material.

2. The carbon brush composite material of the present invention has a "quasi-spherical" structure. It is prepared by using a first-stage material similar to "granulation" and compounded with MoS ₂ with excellent lubrication properties. It has high strength, high density and low resistivity. And the carbon brush composite material has better stability. At the same time, the present invention can obtain composite materials with better performance by using lower temperature and shorter time.

Description of the drawings

Figure 1 is a SEM picture 1 of Example 2 of the present invention;

Figure 2 is the second SEM picture of Example 2 of the present invention.

Detailed ways

The present invention will be further described below.

Example 1:

The highly wear-resistant resin-based carbon brush composite material of this embodiment is mainly prepared from the following raw materials in parts by mass: 60% electrochemical graphite powder, 40% flake graphite powder, and a binder and a dispersant, where the binder is The phenolic resin powder is used in an amount of 15% of the total mass of the electrochemical graphite powder ring and flake graphite powder; the dispersant is industrial alcohol, and the amount is 75% of the total mass of the electrochemical graphite powder ring and flake graphite powder.

The preparation method of the highly wear-resistant resin-based carbon brush composite material of this embodiment is as follows:

S1. Add electrochemical graphite powder and flake graphite powder into the mixer and dry mix for 2 hours, until the temperature rises to 85°C;

S2. Then lower the temperature to 40°C, add phenolic resin powder, and continue kneading;

S3. After adding phenolic resin for 0.5h, add industrial alcohol and continue kneading;

S4. Raise the temperature to 75°C, open the lid and continue kneading for 1 hour, then grind and sieve the paste to obtain the first-stage material;

S5. Knead 95% of the first-stage material in S4 and 5% of the treated MoS ₂ twice for 1 hour, then mold it under a pressure of 180MPa, and then bake it to obtain the carbon brush composite material, in which the baking temperature rises to room temperature -70 ℃, free heating; at 70℃-190℃, the heating rate is 9℃/h, holding for 5h; at 190℃-360℃, the heating rate is 8℃/h, holding for 4h; at 360℃-460℃ When the temperature is 460℃-950℃, the heating rate is 5℃/h and the temperature is maintained for 8h. When the temperature is 460℃-950℃, the heating rate is 8℃/h and the temperature is kept for 6h.

Example 2:

The highly wear-resistant resin-based carbon brush composite material of this embodiment is mainly prepared from the following raw materials in parts by mass: 70% electrochemical graphite powder, 30% flake graphite powder, and a binder and a dispersant, wherein the binder is The amount of phenolic resin powder accounts for 20% of the total mass of the electrochemical graphite powder ring and flake graphite powder; the dispersant is industrial alcohol, and the consumption accounts for 80% of the total mass of the electrochemical graphite powder ring and flake graphite powder.

The preparation method of the highly wear-resistant resin-based carbon brush composite material of this embodiment is as follows:

S1. Add electrochemical graphite powder and flake graphite powder into the mixer and dry mix for 2.5 hours, until the temperature rises to 90°C;

S2. Then lower the temperature to 45°C, add phenolic resin powder, and continue kneading;

S3. After adding phenolic resin for 0.5h, add industrial alcohol and continue kneading;

S4. Raise the temperature to 80°C, open the lid and continue kneading for 1.5 hours, then grind and sieve the paste to obtain the first-stage material;

S5. Knead 97% of the first-stage material in S4 and the treated 3% MoS ₂ for 2 hours, then mold it under a pressure of 190MPa, and then bake it to obtain the carbon brush composite material, in which the baking temperature rises to room temperature -70 ℃, free heating; at 70℃-190℃, the heating rate is 9℃/h, holding for 5h; at 190℃-360℃, the heating rate is 8℃/h, holding for 4h; at 360℃-460℃ When the temperature is 460℃-950℃, the heating rate is 5℃/h and the temperature is maintained for 8h. When the temperature is 460℃-950℃, the heating rate is 8℃/h and the temperature is kept for 6h.

Example 3:

The highly wear-resistant resin-based carbon brush composite material of this embodiment is mainly prepared from the following raw materials in parts by mass: 80% electrochemical graphite powder, 20% flake graphite powder, and a binder and a dispersant, wherein the binder is The amount of phenolic resin powder accounts for 25% of the total mass of electrochemical graphite powder rings and flake graphite powder; the dispersant is industrial alcohol, and the consumption accounts for 85% of the total mass of electrochemical graphite powder rings and flake graphite powder.

The preparation method of the highly wear-resistant resin-based carbon brush composite material of this embodiment is as follows:

S1. Add electrochemical graphite powder and flake graphite powder into the mixer and dry mix for 3 hours until the temperature rises to 95°C;

S2. Then lower the temperature to 50°C, add phenolic resin powder, and continue kneading;

S3. After adding phenolic resin for 0.5h, add industrial alcohol and continue kneading;

S4. Raise the temperature to 85°C, open the lid and continue kneading for 2 hours, then grind and sieve the paste to obtain the first-stage material;

S5. Knead 99% of the first-stage material in S4 and 1% of the treated MoS ₂ twice for 1 hour, then mold it under a pressure of 200MPa, and then bake it to obtain the carbon brush composite material, in which the baking temperature rises to room temperature -70 ℃, free heating; at 70℃-190℃, the heating rate is 9℃/h, holding for 5h; at 190℃-360℃, the heating rate is 8℃/h, holding for 4h; at 360℃-460℃ When the temperature is 460℃-950℃, the heating rate is 5℃/h and the temperature is maintained for 8h. When the temperature is 460℃-950℃, the heating rate is 8℃/h and the temperature is kept for 6h.

Example 4:

The highly wear-resistant resin-based carbon brush composite material of this embodiment is mainly prepared from the following raw materials in parts by mass: 70% electrochemical graphite powder, 30% flake graphite powder, and a binder and a dispersant, where the binder is The amount of phenolic resin powder accounts for 20% of the total mass of the electrochemical graphite powder ring and flake graphite powder; the dispersant is industrial alcohol, and the consumption accounts for 80% of the total mass of the electrochemical graphite powder ring and flake graphite powder.

The preparation method of the highly wear-resistant resin-based carbon brush composite material of this embodiment is as follows:

S1. Add electrochemical graphite powder and flake graphite powder into the mixer and dry mix for 2.5 hours, until the temperature rises to 90°C;

S2. Then lower the temperature to 45°C, add phenolic resin powder, and continue kneading;

S3. After adding phenolic resin for 0.5h, add industrial alcohol and continue kneading;

S4. Raise the temperature to 80°C, open the lid and continue kneading for 1.5 hours, then grind and sieve the paste to obtain the first-stage material;

S5. Knead the 100% first-stage material in S4 for a second time for 2 hours, then mold it under a pressure of 190MPa, and then bake it to obtain the carbon brush composite material. When the baking temperature rises to room temperature -70°C, the temperature is increased freely; at 70°C At -190℃, the heating rate is 9℃/h, and the temperature is maintained for 5 hours; at 190℃-360℃, the heating rate is 8℃/h, and the temperature is kept for 4h; at 360℃-460℃, the heating rate is 5℃/h , keep warm for 8h; at 460℃-950℃, the heating rate is 8℃/h, keep warm for 6h.

Performance tests were conducted on the highly wear-resistant resin-based carbon brush composite materials of the above embodiments, and the results are shown in Table 1.

Table 1 Various properties of Examples 1-4

The carbon brush composite material produced through the above process has a volume density of 1.6-1.7g/cm ³ , a resistivity of 20-30μΩ·m, a Rockwell hardness of 75-90HR, a friction coefficient of ≤0.25, and a 50h wear loss of 0.15- 0.3mm, the voltage drop at the contact point is 1.5-2.5V.

As shown in Figures 1 and 2, it can be seen from the SEM image of the carbon brush composite material in Example 2 that the carbon brush composite material uses high-purity electrochemical graphite powder, has very few raw material impurities, increases the true specific gravity, and also has good resistance to Oxidation, thermal conductivity and chemical stability. Using an appropriate amount of phenolic resin will form resin coke during the roasting process, which can improve the strength and hardness of the product. Molybdenum disulfide easily slides along the SS surface under the action of shear force, which can reduce friction; in addition, it is diamagnetic and can assist rectification and commutation under high temperature and high pressure. Each phase of the carbon brush composite material prepared by this method is evenly distributed, which effectively increases the binding force between the aggregate carbon phase and other phases. It can also reduce the occurrence of micro-cracks in the material, improve the comprehensive mechanical properties of the composite material, and has "like "Spherical" type structure, using a similar "granulated" first-stage material and then compounding it with MoS ₂ with excellent lubrication properties to prepare carbon brush composite materials with high strength, high density, low resistivity, and better stability.

This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and the core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the present invention ideas, there will be changes in the specific implementation and scope of application, and changes and improvements to the present invention will be possible without exceeding the concept and scope specified in the appended claims. In summary, this specification The contents should not be construed as limitations of the invention.

Claims (6)

1. A high wear-resistant resin-based carbon brush composite material is characterized in that: comprises the following components in weight: 60-80% of electrochemical graphite powder and 20-40% of flake graphite powder.

2. The high wear-resistant resin-based carbon brush composite material according to claim 1, wherein: the graphite powder also comprises 15-25% of adhesive by weight of the total weight of the electrochemical graphite powder and the flake graphite powder.

3. The high wear-resistant resin-based carbon brush composite material according to claim 2, wherein: and also comprises dispersant accounting for 75-85% of the total weight of the electrochemical graphite powder and the flake graphite powder.

4. The high wear-resistant resin-based carbon brush composite material according to claim 3, wherein: the adhesive is phenolic resin powder.

5. The high wear-resistant resin-based carbon brush composite material according to claim 3, wherein: the dispersing agent is industrial alcohol.

6. A method for preparing a high wear-resistant resin-based carbon brush composite material according to any one of claims 1 to 5, characterized in that: the method comprises the following steps:

s1, carrying out dry powder hot mixing on 60-80% of fossil toner and 20-40% of flake graphite powder at a temperature of 85-100 ℃ for 2-3 hours;

s2, after the temperature is reduced to 40-50 ℃, adding 15-25% of phenolic resin powder into the mixed powder obtained in the step S1, and continuing kneading;

s3, continuously kneading for 0.5-1h, adding 75-85% industrial alcohol into the mixed paste obtained in the step S2, heating to 70-90 ℃, and continuously kneading for 1-2h;

s4, grinding and screening the paste in the step S3 to obtain a first-stage material;

s5, 90-100% of the first-stage material in the step S4 and less than 10% of MoS after simple sphericization ₂ Carrying out secondary kneading at room temperature for 1-3h;

s6, carrying out compression molding on the pressed powder of the secondary paste obtained in the step S5 under 160-200MPa, and then freely heating at the room temperature of-70 ℃; at 70-190 ℃, the heating rate is 9 ℃/h, and the temperature is kept for 5h; at 190-360 ℃, the heating rate is 8 ℃/h, and the temperature is kept for 4h; at 360-460 ℃, the heating rate is 5 ℃/h, and the temperature is kept for 8h; and (3) roasting at the temperature of 460-950 ℃ at a heating rate of 8 ℃/h and a heating curve of 6h of heat preservation, and processing to obtain the carbon brush composite material.