CN110453101B - Metallic copper flake graphite reinforced copper matrix composite material and preparation method and application thereof - Google Patents

Abstract

The invention discloses a graphite-reinforced copper-based composite material with metal copper flakes. Prepared after sintering; wherein, the hard particles are selected from one or more of SiC particles, B ₄ C particles, TiC particles, Al ₂ O ₃ particles, SiO ₂ particles, Si ₃ N ₄ particles and AlN particles; The metal copper flake graphite is to sensitize and activate the layered graphite flake in turn, so that the surface and the interlayer of the graphite flake adsorb a layer of reducing colloid, and form a nucleation site; It is obtained by plating metal copper layers on the surface and interlayers of graphite. The invention also provides a preparation method and application of the metal copper flake graphite reinforced copper matrix composite material. The copper flake graphite reinforced copper matrix composite material of the invention can improve the bonding strength of the flake graphite and the copper matrix, and increase the mechanical and friction and wear resistance properties of the copper matrix composite material.

Description

Metallic copper flake graphite reinforced copper matrix composite material and preparation method and application thereof

technical field

The invention relates to the technical field of composite material preparation, in particular to a graphite-reinforced copper-based composite material sandwiched with metal copper flakes, a preparation method and application thereof.

Background technique

Copper matrix composites are widely used as friction materials due to their good workability, excellent tribological properties and good thermal conductivity. Hard particles are often added to copper-based composite materials to strengthen the second phase, and the addition of hard particles can effectively improve the wear resistance and friction coefficient of the composite material. However, the addition of hard particles is easy to cause damage to the wear surface, and at the same time, the hard particles are easy to fall off from the copper matrix to cause abrasive wear. In order to overcome this problem, solid lubricants are often added to copper-based composites to stabilize the friction pair, and reduce the adhesive contact of the friction pair by forming a lubrication transfer layer on the surface of the pair. Among solid lubricants, graphite has excellent lubricity, high thermal conductivity, damping resistance and high temperature stability, so graphite is the most common solid lubricant in copper matrix composites.

However, a large number of literatures have reported that the weak interfacial bonding force between copper and graphite will cause the graphite to be pulled out from the matrix during friction and wear, thus failing to achieve its lubricating effect. Graphite surface metallization is an effective way to improve the interface bonding between graphite and copper matrix. However, the surface metallized graphites used in previous studies are mainly spheroidal graphites, graphite powders, or graphite fibers with smaller sizes. However, there are few reports on the relationship between large scale graphite flakes and copper (>200 μm in diameter) matrix. Compared with other types of graphite, large-scale flake graphite has the advantages of low density, low price, small specific surface area, and high thermal conductivity along the horizontal direction, and is used in friction materials working under high-speed and heavy-load conditions, such as automobiles, high-speed trains, etc. Friction materials for brakes such as windmills and aerospace. In addition, studies have shown that the surface metallization of large-sized particles does not improve the interfacial bonding strength as effectively as the surface metallization of small-sized particles.

SUMMARY OF THE INVENTION

In order to improve the interface strength between the flake graphite and the copper matrix, and increase the mechanical and friction and wear resistance properties of the copper matrix composite material, the present invention provides a metal copper flake graphite reinforced copper matrix composite material and a preparation method thereof.

In order to solve the above technical problems, the present invention provides a metal copper flake graphite reinforced copper matrix composite material, which is composed of 1-20wt.% hard particles, 5-30wt.% metal copper flake graphite and the balance of copper The powder is prepared by hot pressing and sintering after molding;

Wherein, the hard particles are selected from one or more of SiC particles, B ₄ C particles, TiC particles, Al ₂ O ₃ particles, SiO ₂ particles, Si ₃ N ₄ particles and AlN particles;

The preparation method of described metal copper flake graphite is:

The layered graphite flakes are sequentially sensitized and activated, so that a layer of reducing colloid is adsorbed on the surface and between the layers of the graphite flakes, and a nucleation site is formed on the reducing colloid; and

The metal copper layer is plated on the surface and between the layers of the layered graphite flake by the method of electroless plating, so as to obtain the metal copper flake graphite.

Further, the size of the hard particles is 600 nm˜300 μm, and further, the size of the hard particles is 10˜20 μm.

Further, the copper powder is selected from one or more of atomized copper powder, electrolytic copper powder, copper oxide powder, red copper powder, bronze powder and brass powder. Further, the size of the copper powder is 1-45 μm.

Further, the size of the graphite with metal copper flakes is 100-300 μm.

Further, the layered graphite flakes are prepared through the following steps:

Mix the natural flake graphite with mixed acid and intercalating agent evenly, and stir and react at 35～40℃ for 1～2h; after the reaction, wash the natural flake graphite with water, filter, and then dry, and keep at 300～400℃ for 1 hour. ~2 min to obtain the layered flake graphite.

Further, the size of the natural flake graphite is 100-300 μm.

Further, the mixed acid is formed by mixing perchloric acid and phosphoric acid, and the volume ratio of the two is 3-6:0.5-1.5; the intercalating agent is potassium permanganate.

Further, the content ratio of the mixed acid, potassium permanganate and natural flake graphite is (3.5-7.5ml):(0.2-0.6g):(3-5g).

In the present invention, the activation is to allow the surface of the flake graphite to absorb a layer of metal Pd. Pd is a very strong catalytically active metal. In the process of electroless metal plating, the metal coating will nucleate and grow with Pd as the center. Therefore, the electroless plating process can be carried out smoothly; the adsorption of metal Pd is obtained by the reduction of Pd ²⁺ by the Sn(OH)Cl colloid adsorbed on the surface of the carbon fiber after sensitization treatment. Further, the formula of the sensitization solution is: SnCl ₂ , 20g/L; 37wt% HCl, 40mL/L; the remainder is deionized water; the formula of the activation solution is: PdCl ₂ , 0.2g/L; 37wt% HCl , 5mL/L; the remainder is deionized water.

further,

The formula of electroless Cu plating solution is: copper sulfate pentahydrate, 14-18g/L; disodium EDTA, 20-30g/L; potassium sodium tartrate, 15-25g/L; formaldehyde solution, 12-16mL/L L; the rest are deionized water; the pH adjusting agent is 50wt.% NaOH solution, and the pH value of the adjusted solution is 13.5-14; the temperature of electroless Cu plating is 35-45°C.

Further, it also includes the steps of washing and drying the flake graphite with metal layer obtained after electroless plating in an alcohol solution.

The present invention also provides a method for preparing the described copper-clad copper flake graphite reinforced copper-based material, comprising the following steps:

Take a formula amount of hard particles, metal copper flake graphite and copper powder, add 0.2-0.5wt.% of a mixing agent, and mix evenly to obtain a composite powder; the composite powder is cold-pressed, and the cold-pressing pressure is 450-550MPa, and the pressure holding time is 30-60s; and hot-pressing and sintering the green body after cold-pressing, first heating up to 380-420°C, and keeping the temperature for 2-2.5h to make the mixture completely volatilize; 880～920 ℃, heat preservation 1～1.5h, namely obtain the described copper-based copper-clad metal flake graphite reinforced copper-based material; wherein the vacuum degree in the furnace is 10 ^-2 Pa, the pressure is 2～3Mpa, and the heating rate is 15～20 ℃/ min.

The invention also provides the application of the graphite-reinforced copper-based material sandwiched with metal copper flakes in friction materials.

Beneficial effects of the present invention:

Compared with the traditional direct addition of flake graphite and copper-plated flake graphite, the metal-coated copper flake graphite used in the present invention can greatly improve the bonding strength between the flake graphite and the copper matrix, and greatly improve the mechanical properties of the copper-based composite material. and friction and wear properties. It has broad application prospects in the field of friction materials requiring high friction stability and high wear resistance.

Description of drawings

Fig. 1 is the SEM topography of raw material flake graphite;

Fig. 2 is the SEM topography of the layered graphite flake prepared in Example 1;

Fig. 3 is the SEM topography of the graphite interlayer flake prepared by Example 1;

FIG. 4 is the EDS image of the surface of the graphite flake with metal copper layer prepared in Example 1. FIG.

Fig. 5 is the metallographic photograph of the composite material of the sample after vacuum hot pressing sintering;

Figures 6a and d are diagrams and schematic diagrams of the interface bonding between graphite flakes and copper in the composite material prepared in Comparative Example 1; Figures 6b and e are diagrams and schematic diagrams of the interface bonding between graphite flakes and copper in the composite material prepared in Comparative Example 2; Figure 6c and f are the interface bonding diagram and schematic diagram of flake graphite and copper in the composite material prepared in Example 1.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

Example 1

The present embodiment discloses a preparation method of metal copper flake graphite reinforced copper matrix composite material, comprising the following steps:

(1) At room temperature, put 5ml of perchloric acid and 1ml of phosphoric acid into a glass beaker and mix evenly to obtain a mixed acid, then add 0.4g potassium permanganate, stir slowly to dissolve it in the mixed acid, and finally add 4g Flake graphite and stir well to mix well. A glass beaker containing perchloric acid, phosphoric acid, potassium permanganate and flake graphite was placed in a constant temperature water bath with a water temperature of 40°C for 60 min. During the reaction, stirring should be continued to ensure a uniform reaction. After the reaction, washed with water for several times, and filtered out the precipitated graphite flakes and dried at 60°C. Finally, the obtained flake graphite was put into a muffle furnace, and the muffle furnace was raised to 300° C. and kept for 60 s. Turn off the power supply of the muffle furnace, and after the temperature in the furnace drops below 100°C, the flake graphite is taken out from the muffle furnace to obtain layered flake graphite. The original morphology of graphite flakes is shown in Figure 1, and the morphology of the obtained layered graphite flakes is shown in Figure 2.

(2) Put the graphite flakes obtained through the treatment in the step (1) into the sensitizing solution and keep stirring, take it out after 15 minutes, clean it with deionization, and dry at room temperature. The ratio of the sensitizing solution is: SnCl ₂ , 20 g/L; 37 wt% HCl, 40 mL/L; the remainder is deionized water. The sensitized graphite flakes were put into the activation solution and stirred continuously, taken out after 15 minutes, cleaned with deionization, and dried at room temperature. The ratio of the activation solution is: PdCl ₂ , 0.2 g/L; 37 wt% HCl, 5 mL/L; the remainder is deionized water.

(3) Using the method of electroless copper plating, a metal layer is plated on the surface of the layered flake graphite and between the graphite layers. The layered flake graphite obtained in the (1) step is put into a constant temperature water bath, and the plating solution required for chemical copper plating is carried out in the water bath. The formula of the electroless Cu plating solution is: copper sulfate pentahydrate, 14g/L; disodium EDTA, 20g/L; potassium sodium tartrate, 15g/L; formaldehyde solution, 12mL/L, and the rest are deionized water. The constant temperature water bath was heated to 35° C. and kept for 10 minutes, then 50wt.% NaOH solution was added to adjust the pH value of the solution to 13.5-14, and the temperature was kept for 30 minutes with constant stirring. After the reaction, the graphite flakes are taken out, put into an ethanol solution for ultrasonic cleaning immediately, and dried in a drying oven to obtain graphite flakes with metal copper. The morphology of the obtained graphite with metal-clad copper flakes is shown in Figure 3. The surface composition of the obtained graphite with metallic copper flakes is shown in FIG. 4 .

(4) Mixing: take 10g of metal copper flake graphite, 2g of SiO ₂ particles and 88g of electrolytic copper powder into a mixing tank to obtain mixed powder. Add 0.2 ml of mixing agent to the mixing tank. Put the mixing tank into the three-dimensional swing mixer and mix for 4 hours. The mixing machine rotates at a speed of 400 r/min. After mixing, the composite powder is obtained.

的不锈钢模具中，在液压机下冷压成型。冷压压力为500MPa，保压时间为30s。冷压成型后得到成型试样。(5) Cold-pressing molding: The composite powder is packed into the inner diameter of

It is cold-pressed under a hydraulic press in a stainless steel mold. The cold pressing pressure is 500MPa, and the holding time is 30s. After cold pressing, the formed samples were obtained.

的石墨模具中，在真空热压炉中进行热压烧结。炉内真空度为10^-2Pa，炉内升温速率为20℃/min，升温至400℃保温2h，混料剂可从试样中全部挥发。继续升温至900℃保温并加压，其中压力为2～3MPa，保温时间为1h。保温时间结束后，关掉电源，卸载压力，待炉内温度降至100℃以下，将热压件从真空热压炉中取出，去模具，得到夹金属铜鳞片石墨增强铜基复合材料。真空热压烧结后试样的复合材料的金相照片如图5所示。复合材料中鳞片石墨与铜的界面结合情况和界面结合示意图如图6c和f所示。(6) Hot-pressing sintering: the cold-pressed sample is loaded into the inner diameter of

In the graphite mold, the hot pressing sintering is carried out in a vacuum hot pressing furnace. The vacuum degree in the furnace is 10 ^-2 Pa, the heating rate in the furnace is 20 ℃/min, and the temperature is raised to 400 ℃ for 2 hours, and the mixing agent can be completely volatilized from the sample. Continue to heat up to 900° C. for heat preservation and pressurization, wherein the pressure is 2-3 MPa, and the heat preservation time is 1 h. After the holding time is over, turn off the power and unload the pressure. When the temperature in the furnace drops below 100°C, the hot-pressed parts are taken out from the vacuum hot-pressing furnace and removed from the mold to obtain the metal-copper flake graphite-reinforced copper-based composite material. The metallographic photograph of the composite material of the sample after vacuum hot pressing sintering is shown in Figure 5. The interfacial bonding situation and interfacial bonding of flake graphite and copper in the composites are shown in Fig. 6c and f.

Example 2

The present embodiment discloses a preparation method of a graphite-reinforced copper-based composite material with metal copper flakes, comprising the following steps:

(1) At room temperature, put 5ml of perchloric acid and 1ml of phosphoric acid into a glass beaker and mix evenly to obtain a mixed acid, then add 0.4g potassium permanganate, stir slowly to dissolve it in the mixed acid, and finally add 4g Flake graphite and stir well to mix well. A glass beaker containing perchloric acid, phosphoric acid, potassium permanganate and flake graphite was placed in a constant temperature water bath with a water temperature of 40°C for 60 min. During the reaction, stirring should be continued to ensure a uniform reaction. After the reaction, washed with water for several times, and filtered out the precipitated graphite flakes and dried at 60°C. Finally, the obtained flake graphite was put into a muffle furnace, and the muffle furnace was raised to 300° C. and kept for 60 s. Turn off the power supply of the muffle furnace, and after the temperature in the furnace drops below 100°C, the flake graphite is taken out from the muffle furnace to obtain layered flake graphite.

(2) Put the graphite flakes obtained through the treatment in the step (1) into the sensitizing solution and keep stirring, take it out after 15 minutes, clean it with deionization, and dry at room temperature. The ratio of the sensitizing solution is: SnCl ₂ , 20 g/L; 37 wt% HCl, 40 mL/L; the remainder is deionized water. The sensitized graphite flakes were put into the activation solution and stirred continuously, taken out after 15 minutes, cleaned with deionization, and dried at room temperature. The ratio of the activation solution is: PdCl ₂ , 0.2 g/L; 37 wt% HCl, 5 mL/L; the remainder is deionized water.

(3) Using the method of electroless copper plating, a metal layer is plated on the surface of the layered flake graphite and between the graphite layers. The layered flake graphite obtained in the (1) step is put into a constant temperature water bath, and the plating solution required for chemical copper plating is carried out in the water bath. The formula of electroless Cu plating solution is: copper sulfate pentahydrate, 16g/L; disodium EDTA, 25g/L; potassium sodium tartrate, 20g/L; formaldehyde solution, 13mL/L, and the rest are deionized water. The constant temperature water bath was heated to 35° C. and kept for 10 minutes, then 50wt.% NaOH solution was added to adjust the pH value of the solution to 13.5-14, and the temperature was kept for 30 minutes with constant stirring. After the reaction, the graphite flakes are taken out, put into an ethanol solution for ultrasonic cleaning immediately, and dried in a drying oven to obtain graphite flakes with metal copper.

(4) Mixing: take 8g of metal copper flake graphite, 1g of _SiO2 particles and 91g of electrolytic copper powder into a mixing tank to obtain mixed powder. Add 0.2 ml of mixing agent to the mixing tank. Put the mixing tank into the three-dimensional swing mixer and mix for 4 hours. The mixing machine rotates at a speed of 400 r/min. After mixing, the composite powder is obtained.

的不锈钢模具中，在液压机下冷压成型。冷压压力为500MPa，保压时间为30s。冷压成型后得到成型试样。(5) Cold-pressing molding: The composite powder is packed into the inner diameter of

It is cold-pressed under a hydraulic press in a stainless steel mold. The cold pressing pressure is 500MPa, and the holding time is 30s. After cold pressing, the formed samples were obtained.

的石墨模具中，在真空热压炉中进行热压烧结。炉内真空度为10^-2Pa，炉内升温速率为20℃/min，升温至400℃保温2h，混料剂可从试样中全部挥发。继续升温至900℃保温并加压，其中压力为2～3MPa，保温时间为1h。保温时间结束后，关掉电源，卸载压力，待炉内温度降至100℃以下，将热压件从真空热压炉中取出，去模具，得到夹金属铜鳞片石墨增强铜基复合材料。(6) Hot-pressing sintering: the cold-pressed sample is loaded into the inner diameter of

In the graphite mold, the hot pressing sintering is carried out in a vacuum hot pressing furnace. The vacuum degree in the furnace is 10 ^-2 Pa, the heating rate in the furnace is 20 ℃/min, and the temperature is raised to 400 ℃ for 2 hours, and the mixing agent can be completely volatilized from the sample. Continue to heat up to 900° C. for heat preservation and pressurization, wherein the pressure is 2-3 MPa, and the heat preservation time is 1 h. After the holding time is over, turn off the power and unload the pressure. When the temperature in the furnace drops below 100°C, the hot-pressed parts are taken out from the vacuum hot-pressing furnace and removed from the mold to obtain the metal-copper flake graphite-reinforced copper-based composite material.

Example 3

The present embodiment discloses a preparation method of a graphite-reinforced copper-based composite material with metal copper flakes, comprising the following steps:

(1) At room temperature, put 5ml of perchloric acid and 1ml of phosphoric acid into a glass beaker and mix evenly to obtain a mixed acid, then add 0.4g potassium permanganate, stir slowly to dissolve it in the mixed acid, and finally add 4g Flake graphite and stir well to mix well. A glass beaker containing perchloric acid, phosphoric acid, potassium permanganate and flake graphite was placed in a constant temperature water bath with a water temperature of 40°C for 60 min. During the reaction, stirring should be continued to ensure a uniform reaction. After the reaction, washed with water for several times, and filtered out the precipitated graphite flakes and dried at 60°C. Finally, the obtained flake graphite was put into a muffle furnace, and the muffle furnace was raised to 300° C. and kept for 60 s. Turn off the power supply of the muffle furnace, and after the temperature in the furnace drops below 100°C, the flake graphite is taken out from the muffle furnace to obtain layered flake graphite.

(2) Put the graphite flakes obtained through the treatment in the step (1) into the sensitizing solution and keep stirring, take it out after 15 minutes, clean it with deionization, and dry at room temperature. The ratio of the sensitizing solution is: SnCl ₂ , 20 g/L; 37 wt% HCl, 40 mL/L; the remainder is deionized water. The sensitized graphite flakes were put into the activation solution and stirred continuously, taken out after 15 minutes, cleaned with deionization, and dried at room temperature. The ratio of the activation solution is: PdCl ₂ , 0.2 g/L; 37 wt% HCl, 5 mL/L; the remainder is deionized water.

(3) Using the method of electroless copper plating, a metal layer is plated on the surface of the layered flake graphite and between the graphite layers. The layered flake graphite obtained in the (1) step is put into a constant temperature water bath, and the plating solution required for chemical copper plating is carried out in the water bath. The formula of electroless Cu plating solution is: copper sulfate pentahydrate, 16g/L; disodium EDTA, 25g/L; potassium sodium tartrate, 20g/L; formaldehyde solution, 13mL/L, and the rest are deionized water. The constant temperature water bath was heated to 35° C. and kept for 10 minutes, then 50wt.% NaOH solution was added to adjust the pH value of the solution to 13.5-14, and the temperature was kept for 30 minutes with constant stirring. After the reaction, the graphite flakes are taken out, put into an ethanol solution for ultrasonic cleaning immediately, and dried in a drying oven to obtain graphite flakes with metal copper.

(4) Mixing: take 9g of graphite with metal copper flakes, 2g of alumina particles and 89g of bronze powder into a mixing tank to obtain mixed powder. Add 0.2 ml of mixing agent to the mixing tank. Put the mixing tank into the three-dimensional swing mixer and mix for 4 hours. The mixing machine rotates at a speed of 400 r/min. After mixing, the composite powder is obtained.

的不锈钢模具中，在液压机下冷压成型。冷压压力为500MPa，保压时间为30s。冷压成型后得到成型试样。(5) Cold-pressing molding: The composite powder is packed into the inner diameter of

It is cold-pressed under a hydraulic press in a stainless steel mold. The cold pressing pressure is 500MPa, and the holding time is 30s. After cold pressing, the formed samples were obtained.

的石墨模具中，在真空热压炉中进行热压烧结。炉内真空度为10^-2Pa，炉内升温速率为20℃/min，升温至400℃保温2h，混料剂可从试样中全部挥发。继续升温至900℃保温并加压，其中压力为2～3MPa，保温时间为1h。保温时间结束后，关掉电源，卸载压力，待炉内温度降至100℃以下，将热压件从真空热压炉中取出，去模具，得到夹金属铜鳞片石墨增强铜基复合材料。(6) Hot-pressing sintering: the cold-pressed sample is loaded into the inner diameter of

In the graphite mold, the hot pressing sintering is carried out in a vacuum hot pressing furnace. The vacuum degree in the furnace is 10 ^-2 Pa, the heating rate in the furnace is 20 ℃/min, and the temperature is raised to 400 ℃ for 2 hours, and the mixing agent can be completely volatilized from the sample. Continue to heat up to 900° C. for heat preservation and pressurization, wherein the pressure is 2-3 MPa, and the heat preservation time is 1 h. After the holding time is over, turn off the power and unload the pressure. When the temperature in the furnace drops below 100°C, the hot-pressed parts are taken out from the vacuum hot-pressing furnace and removed from the mold to obtain the metal-copper flake graphite-reinforced copper-based composite material.

Example 4

The present embodiment discloses a preparation method of metal copper flake graphite reinforced copper matrix composite material, comprising the following steps:

(1) At room temperature, put 5ml of perchloric acid and 1ml of phosphoric acid into a glass beaker and mix evenly to obtain a mixed acid, then add 0.4g potassium permanganate, stir slowly to dissolve it in the mixed acid, and finally add 4g Flake graphite and stir well to mix well. A glass beaker containing perchloric acid, phosphoric acid, potassium permanganate and flake graphite was placed in a constant temperature water bath with a water temperature of 40°C for 60 min. During the reaction, stirring should be continued to ensure a uniform reaction. After the reaction, washed with water for several times, and filtered out the precipitated graphite flakes and dried at 60°C. Finally, the obtained flake graphite was put into a muffle furnace, and the muffle furnace was raised to 300° C. and kept for 60 s. Turn off the power supply of the muffle furnace, and after the temperature in the furnace drops below 100°C, the flake graphite is taken out from the muffle furnace to obtain layered flake graphite.

(2) Put the graphite flakes obtained through the treatment in the step (1) into the sensitizing solution and keep stirring, take it out after 15 minutes, clean it with deionization, and dry at room temperature. The ratio of the sensitizing solution is: SnCl ₂ , 20 g/L; 37 wt% HCl, 40 mL/L; the remainder is deionized water. The sensitized graphite flakes were put into the activation solution and stirred continuously, taken out after 15 minutes, cleaned with deionization, and dried at room temperature. The ratio of the activation solution is: PdCl ₂ , 0.2 g/L; 37 wt% HCl, 5 mL/L; the remainder is deionized water.

(3) Using the method of electroless copper plating, a metal layer is plated on the surface of the layered flake graphite and between the graphite layers. The layered flake graphite obtained in the (1) step is put into a constant temperature water bath, and the plating solution required for chemical copper plating is carried out in the water bath. The formula of electroless Cu plating solution is: copper sulfate pentahydrate, 16g/L; disodium EDTA, 25g/L; potassium sodium tartrate, 20g/L; formaldehyde solution, 13mL/L, and the rest are deionized water. The constant temperature water bath was heated to 35° C. and kept for 10 minutes, then 50wt.% NaOH solution was added to adjust the pH value of the solution to 13.5-14, and the temperature was kept for 30 minutes with constant stirring. After the reaction, the graphite flakes are taken out, put into an ethanol solution for ultrasonic cleaning immediately, and dried in a drying oven to obtain graphite flakes with metal copper.

(4) Mixing: take 9g of metal copper flake graphite, 1g of silicon dioxide particles, 1g of alumina particles and 89g of electrolytic copper powder into a mixing tank to obtain mixed powder. Add 0.2 ml of mixing agent to the mixing tank. Put the mixing tank into the three-dimensional swing mixer and mix for 4 hours. The mixing machine rotates at a speed of 400 r/min. After mixing, the composite powder is obtained.

的不锈钢模具中，在液压机下冷压成型。冷压压力为500MPa，保压时间为30s。冷压成型后得到成型试样。(5) Cold-pressing molding: The composite powder is packed into the inner diameter of

It is cold-pressed under a hydraulic press in a stainless steel mold. The cold pressing pressure is 500MPa, and the holding time is 30s. After cold pressing, the formed samples were obtained.

的石墨模具中，在真空热压炉中进行热压烧结。炉内真空度为10^-2Pa，炉内升温速率为20℃/min，升温至400℃保温2h，混料剂可从试样中全部挥发。继续升温至900℃保温并加压，其中压力为2～3MPa，保温时间为1h。保温时间结束后，关掉电源，卸载压力，待炉内温度降至100℃以下，将热压件从真空热压炉中取出，去模具，得到夹金属铜鳞片石墨增强铜基复合材料。(6) Hot-pressing sintering: the cold-pressed sample is loaded into the inner diameter of

In the graphite mold, the hot pressing sintering is carried out in a vacuum hot pressing furnace. The vacuum degree in the furnace is 10 ^-2 Pa, the heating rate in the furnace is 20 ℃/min, and the temperature is raised to 400 ℃ for 2 hours, and the mixing agent can be completely volatilized from the sample. Continue to heat up to 900° C. for heat preservation and pressurization, wherein the pressure is 2-3 MPa, and the heat preservation time is 1 h. After the holding time is over, turn off the power and unload the pressure. When the temperature in the furnace drops below 100°C, the hot-pressed parts are taken out of the vacuum hot-pressing furnace and removed from the mold to obtain a copper-based copper-based composite material with metal copper flakes and graphite.

Comparative Example 1

(1) Mixing: get 6.6g of graphite flakes that are not processed by step (1), (2), (3) in Example 1, _2g SiO particles and 91.4g electrolytic copper powder are put into the mixing tank to obtain Mix powder. Add 0.2 ml of mixing agent to the mixing tank. Put the mixing tank into the three-dimensional swing mixer and mix for 4 hours. The mixing machine rotates at a speed of 400 r/min. After mixing, the composite powder is obtained. Take 6.6g of graphite flakes that have not been treated with metal copper, because the weight of 6.6g of graphite flakes after treatment with metal copper is 10g.

的不锈钢模具中，在液压机下冷压成型。冷压压力为500MPa，保压时间为30s。冷压成型后得到成型试样。(2) Cold-pressing molding: the composite powder is packed into the inner diameter of

It is cold-pressed under a hydraulic press in a stainless steel mold. The cold pressing pressure is 500MPa, and the holding time is 30s. After cold pressing, the formed samples were obtained.

的石墨模具中，在真空热压炉中进行热压烧结。炉内真空度为10^-2Pa，炉内升温速率为20℃/min，升温至400℃保温2h，混料剂可从试样中全部挥发。继续升温至900℃保温并加压，其中压力为2～3MPa，保温时间为1h。保温时间结束后，关掉电源，卸载压力，待炉内温度降至100℃以下，将热压件从真空热压炉中取出，去模具，得到鳞片石墨增强铜基复合材料。复合材料中鳞片石墨与铜的界面结合情况和界面结合示意图如图6a和d所示。(3) Hot-pressing sintering: the cold-pressed sample is loaded into the inner diameter of

In the graphite mold, the hot pressing sintering is carried out in a vacuum hot pressing furnace. The vacuum degree in the furnace is 10 ^-2 Pa, the heating rate in the furnace is 20 ℃/min, and the temperature is raised to 400 ℃ for 2 hours, and the mixing agent can be completely volatilized from the sample. Continue to heat up to 900° C. for heat preservation and pressurization, wherein the pressure is 2-3 MPa, and the heat preservation time is 1 h. After the holding time is over, turn off the power and unload the pressure. When the temperature in the furnace drops below 100°C, the hot-pressed parts are taken out from the vacuum hot-pressing furnace and removed from the mold to obtain the flake graphite reinforced copper matrix composite material. The interfacial bonding situation and interfacial bonding of flake graphite and copper in the composites are shown in Figures 6a and d.

Comparative Example 2

(1) Get the flake graphite that has not been processed in step (1) in Example 1, put it in the sensitizing solution and stir constantly, take out after 15min and clean it with deionization, and dry at room temperature. The ratio of the sensitizing solution is: SnCl ₂ , 20 g/L; 37 wt% HCl, 40 mL/L; the remainder is deionized water. The sensitized graphite flakes were put into the activation solution and stirred continuously, taken out after 15 minutes, cleaned with deionization, and dried at room temperature. The ratio of the activation solution is: PdCl ₂ , 0.2 g/L; 37 wt% HCl, 5 mL/L; the remainder is deionized water.

(2) Using the method of electroless copper plating, a metal layer is plated on the surface of the flake graphite treated in step (1). The layered flake graphite obtained in the (1) step is put into a constant temperature water bath, and the plating solution required for chemical copper plating is carried out in the water bath. The formula of electroless Cu plating solution is: copper sulfate pentahydrate, 16g/L; disodium EDTA, 25g/L; potassium sodium tartrate, 20g/L; formaldehyde solution, 13mL/L, and the rest are deionized water. The constant temperature water bath was heated to 35° C. and kept for 10 minutes, then 50wt.% NaOH solution was added to adjust the pH value of the solution to 13.5-14, and the temperature was kept for 30 minutes with constant stirring. After the reaction, the graphite flakes are taken out, put into an ethanol solution for ultrasonic cleaning immediately, and dried in a drying oven to obtain copper-plated graphite flakes on the surface.

(3) Mixing: take 9.2g of copper-plated flake graphite on the surface, 2g of _SiO2 particles and 91.4g of electrolytic copper powder into a mixing tank to obtain mixed powder. Add 0.2 ml of mixing agent to the mixing tank. Put the mixing tank into the three-dimensional swing mixer and mix for 4 hours. The mixing machine rotates at a speed of 400 r/min. After mixing, the composite powder is obtained. Taking 9.2g of copper-plated flake graphite on the surface is because the weight of 6.6g of flake graphite after copper plating is 9.2g, and the weight of 6.6g of flake graphite after treatment with metal copper is 10g.

的不锈钢模具中，在液压机下冷压成型。冷压压力为500MPa，保压时间为30s。冷压成型后得到成型试样。(4) Cold pressing: the composite powder is packed into the inner diameter of

It is cold-pressed under a hydraulic press in a stainless steel mold. The cold pressing pressure is 500MPa, and the holding time is 30s. After cold pressing, the formed samples were obtained.

的石墨模具中，在真空热压炉中进行热压烧结。炉内真空度为10^-2Pa，炉内升温速率为20℃/min，升温至400℃保温2h，混料剂可从试样中全部挥发。继续升温至900℃保温并加压，其中压力为2～3MPa，保温时间为1h。保温时间结束后，关掉电源，卸载压力，待炉内温度降至100℃以下，将热压件从真空热压炉中取出，去模具，得到表面镀铜鳞片石墨增强铜基复合材料。复合材料中鳞片石墨与铜的界面结合情况和界面结合示意图如图6b和e所示。(5) Hot-pressing sintering: The cold-pressed sample is loaded into the inner diameter of

In the graphite mold, the hot pressing sintering is carried out in a vacuum hot pressing furnace. The vacuum degree in the furnace is 10 ^-2 Pa, the heating rate in the furnace is 20 ℃/min, and the temperature is raised to 400 ℃ for 2 hours, and the mixing agent can be completely volatilized from the sample. Continue to heat up to 900° C. for heat preservation and pressurization, wherein the pressure is 2-3 MPa, and the heat preservation time is 1 h. After the holding time is over, turn off the power and unload the pressure. When the temperature in the furnace drops below 100°C, the hot-pressed parts are taken out from the vacuum hot-pressing furnace and removed from the mold to obtain copper-coated flake graphite reinforced copper-based composite materials. The interfacial bonding situation and interfacial bonding of flake graphite and copper in the composites are shown in Figure 6b and e.

The relative density, Brinell hardness, compressive strength, friction coefficient and wear rate of the copper matrix composites prepared in Example 1, Comparative Example 1 and Comparative Example 2 were tested, and the results are shown in Table 1 below. It can be seen from Table 1 that the graphite reinforced copper matrix composite with metal copper flakes has the highest relative density, Brinell hardness, compressive strength and friction coefficient, and has the lowest wear rate.

Table 1 Example 1, the test results of the copper-based composite materials prepared in Comparative Examples 1-2

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims (9)

1. a kind of metal copper flake graphite reinforced copper-based composite material, it is characterized in that, by the hard particle of 1～20wt%, the metal copper flake graphite of 5～30wt% and the copper powder of surplus through hot pressing after molding prepared by sintering; Wherein, the hard particles are selected from one or more of SiC particles, B ₄ C particles, TiC particles, Al ₂ O ₃ particles, SiO ₂ particles, Si ₃ N ₄ particles and AlN particles; The preparation method of described metal copper flake graphite is: The layered graphite flakes are sequentially sensitized and activated, so that a layer of reducing colloid is adsorbed on the surface and between the layers of the graphite flakes, and a nucleation site is formed on the reducing colloid; and Metallic copper layers are plated on the surface and between layers of the layered graphite flakes by using the method of chemical plating to obtain the graphite with metal copper flakes; Described layered flake graphite is prepared through the following steps: Mix the natural flake graphite with mixed acid and intercalating agent evenly, and stir and react at 30～40℃ for 1～2h; after the reaction, wash the natural flake graphite with water, filter and then dry, and keep at 300～400℃ for 1 hour ~2min, the layered flake graphite is obtained. 2. The metal-coated copper flake graphite-reinforced copper-based composite material according to claim 1, wherein the copper powder is selected from the group consisting of atomized copper powder, electrolytic copper powder, copper oxide powder, red copper powder, bronze powder and yellow One or more of copper powders. 3. The graphite-reinforced copper matrix composite material with metal copper flakes according to claim 1, wherein the size of the graphite with metal copper flakes is 100-300 μm. 4. The metal-coated copper flake graphite-reinforced copper-based composite material according to claim 1, wherein the mixed acid is formed by mixing perchloric acid and phosphoric acid, and the volume ratio of the two is 3～6: 0.5～ 1.5; the intercalating agent is potassium permanganate. 5. The metal-coated copper flake graphite reinforced copper-based composite material according to claim 4, wherein the content ratio of the mixed acid, potassium permanganate and natural flake graphite is (3.5～7.5ml): (0.2 ~0.6g): (3~5g). 6. The metal-coated copper flake graphite reinforced copper-based composite material according to claim 1, wherein the formula of the sensitizing solution is: SnCl ₂ , 20～30 g/L; HCl of 37 wt.%, 30～30 g/L 50 mL/L; the remainder is deionized water; The formulation of the activation solution is: PdCl ₂ , 0.1-0.3 g/L; 37 wt.% HCl, 3-6 mL/L; the remainder is deionized water. 7. The metal-coated copper flake graphite-reinforced copper-based composite material according to claim 1, characterized in that, The formula of electroless Cu plating solution is: copper sulfate pentahydrate, 14-18 g/L; disodium EDTA, 20-30 g/L; potassium sodium tartrate, 15-25 g/L; formaldehyde solution, 12 ~16 mL/L; the rest is deionized water; the pH regulator is 50wt.% NaOH solution, and the pH of the solution is adjusted to 13.5-14; the temperature of electroless Cu plating is 30-45 °C. 8. the preparation method of metal copper flake graphite reinforced copper matrix composite material according to any one of claim 1～7, is characterized in that, comprises the following steps: Take the formula amount of hard particles, metal copper flake graphite and copper powder, add 0.2-0.5 wt.% of a mixing agent, and mix evenly to obtain a composite powder; The composite powder is formed by cold pressing, the pressure of cold pressing is 450-550 MPa, and the holding time is 30-60 s; ～2.5h, the mixing agent is completely volatilized; then the temperature is raised to 880～920℃, and the temperature is kept for 1～1.5h, to obtain the copper-based copper flake graphite-reinforced copper-based material; wherein the vacuum degree in the furnace is 10 ^-2 Pa, The pressure is 2～3Mpa, and the heating rate is 15～20℃/min. 9. The application of the metal-clad copper flake graphite reinforced copper-based composite material in friction materials according to any one of claims 1 to 7.

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