CN-121988819-A - Method for carrying out plasma surface treatment on graphene for auxiliary brazing

Abstract

A plasma surface treatment graphene auxiliary brazing method belongs to the field of brazing. The invention aims to solve the problems of poor wettability and low bonding capacity of the existing graphene on the existing metal solder, and solve the problems that the existing graphene surface treatment method has influence on the thermal conductivity of graphene, and has complex process, environmental pollution and inapplicability to base materials with complex shapes and large-area components. The method comprises the steps of treating graphene on the surface of the plasma, and brazing. The method is used for plasma surface treatment graphene auxiliary brazing.

Inventors

• QI JUNLEI
• LIU SHIYAN
• YE ZHENYU
• WANG ZIJIA
• LI CHUN
• SI XIAOQING
• CAO JIAN
• YAN YAOTIAN

Assignees

• 哈尔滨工业大学

Dates

Publication Date

20260508

Application Date

20260326

Claims (10)

1. 1. The method for plasma surface treatment of graphene assisted brazing is characterized by comprising the following steps of: 1. Plasma surface treatment of graphene; Placing graphene in a plasma enhanced chemical vapor deposition device, vacuumizing, introducing argon-hydrogen mixed gas with the flow rate of 40-80 sccm, heating to 300-500 ℃, starting a radio frequency power supply, introducing methane gas with the flow rate of 10-20 sccm, preserving heat for 10-30 min under the conditions of the temperature of 300-500 ℃, the argon-hydrogen mixed gas flow rate of 40-80 sccm and the methane gas flow rate of 10-20 sccm, stopping introducing methane gas after preserving heat, and cooling with a furnace under the argon-hydrogen mixed gas to obtain the graphene subjected to plasma surface treatment; 2. Brazing: And (3) placing the brazing filler metal between the graphene subjected to plasma surface treatment and the base metal to obtain an assembly, placing the assembly in a vacuum brazing furnace, preserving heat at 700-800 ℃, then cooling to 200-400 ℃, cooling to room temperature along with the furnace, and taking out the sample to finish the graphene auxiliary brazing method after the plasma surface treatment.
2. 2. The method of claim 1, wherein the step one is performed by vacuum pumping to a temperature below 0.7 torr.
3. 3. The method for plasma surface treatment graphene-assisted brazing according to claim 1, wherein the volume percentage of hydrogen in the argon-hydrogen mixture gas in the first step is 5% -10%.
4. 4. The method for plasma surface treatment of graphene-assisted brazing according to claim 1, wherein the radio frequency power in the first step is 200-250 w.
5. 5. The method for plasma surface treatment graphene-assisted brazing according to claim 1, wherein the flow ratio of the argon-hydrogen mixture gas to the methane gas in the first step is (4-6): 1.
6. 6. The method for plasma surface-treated graphene-assisted brazing according to claim 1, wherein the brazing filler metal in the second step is AgCuInTi, agCuTi, tiZrNiCu or SnAgCuTi.
7. 7. The method for plasma surface treatment of graphene-assisted brazing according to claim 1, wherein the brazing filler metal in the second step is foil, powder or solder paste.
8. 8. The method for plasma surface treatment graphene-assisted brazing according to claim 1, wherein the base material in the second step is a ceramic matrix composite.
9. 9. The method for plasma surface treatment of graphene-assisted brazing according to claim 1, wherein in the second step, the temperature is raised to 700-800 ℃ at a temperature rise speed of 5-10 ℃ per minute, and the temperature is kept for 5-10 min under the condition that the temperature is 700-800 ℃.
10. 10. The method for plasma surface treatment of graphene-assisted brazing according to claim 1, wherein in the second step, the temperature is reduced to 200-400 ℃ at a temperature reduction speed of 2-10 ℃ per minute, and then the temperature is reduced to room temperature along with the furnace vacuum cooling.

Description

Method for carrying out plasma surface treatment on graphene for auxiliary brazing Technical Field The invention belongs to the field of brazing. Background With the large-scale application of third-generation semiconductor materials such as silicon carbide (SiC), gallium nitride (GaN) and the like, the performance requirements of new energy automobiles, 5G communication, photovoltaic inverters and other front-edge fields on power devices are continuously improved. The continuous rise of the power density and junction temperature of the device makes the traditional heat dissipation substrate gradually show the bottleneck of insufficient heat dissipation capacity when facing the scene of high heat flux density. Electronic devices are gradually developed to be highly integrated and light, and the selection of thermal management materials with light density and high heat conductivity is gradually becoming a new development requirement. The physical performance index of graphene accords with the proposition, and the graphene is applied to a heat conducting substrate to exert the effect of light-weight heat dissipation, so that the graphene is becoming a new development trend. In various connection methods of graphite and dissimilar materials, the vacuum brazing method has the advantages of strong structural adaptability, extremely small workpiece deformation, wide applicable material range, extremely strong process adaptability, stable production efficiency, no oxidation pollution and wider application range. Vacuum brazing is a precise welding process in which workpieces are heated to a temperature above the melting point of the brazing filler metal and below the melting point of the base metal in a high vacuum environment, so that the liquid brazing filler metal fills joints by capillary action and forms metallurgical bonding. In the process of brazing and connecting graphene and dissimilar materials, two main difficulties are provided, namely that the wettability of metal brazing filler metal to the graphene is poor, the liquid brazing filler metal is difficult to spread on the surface of a graphene composite material, and effective metallurgical bonding of an integral member is difficult to realize, and the single-layer graphene has a thermal expansion coefficient of about-3×10 -6 K-1 at room temperature and a negative thermal expansion characteristic, and the thermal expansion coefficients of the metal brazing filler metal are generally larger than 10×10 -6 K-1, so that larger mismatch stress is easy to generate after welding, interface cracks are easy to initiate, buckling deformation is easy to generate, and joint failure is easy to occur. The main reason of the poor wettability of the metal solder to the graphene is that the surface of the graphene is in a completely inert covalent bond structure, atoms are densely arranged and have no active sites, and the conventional general metal solder such as silver copper, copper phosphorus and the like cannot be spread and wetted on the surface of the graphene even in a vacuum high-temperature environment. In the prior researches, patent CN 107492502B discloses that the surface treatment of graphene is carried out by utilizing benzene series steam, and the method can lead the graphene to be better combined with a substrate with low damage and good repeatability. However, the method can affect the thermal conductivity of graphene, and multi-parameter cooperative control is needed, so that the process complexity is high, benzene series steam is easy to pollute and has toxicity. Patent CN 120575150A proposes a method for directly growing a thick graphene film on the surface of silicon oxide, but the method has extremely high requirements on a base material, the surface roughness and cleanliness of the base material can greatly influence the growth condition of graphene, and the product performance fluctuation is large. The graphene and the base material are combined mainly by physical adsorption and weak van der waals force, and are not suitable for the base material with a complex shape and a large-area member. Disclosure of Invention The invention aims to solve the problems of poor wettability and low bonding capacity of the existing graphene on the existing metal solder, solves the problems of influence on the thermal conductivity of the graphene, complex process, environmental pollution and inapplicability to the base metal with complex shape and large-area components in the existing graphene surface treatment method, and further provides a method for assisting in brazing by plasma surface treatment of the graphene. A method for carrying out plasma surface treatment on graphene for auxiliary brazing comprises the following steps: 1. Plasma surface treatment of graphene; Placing graphene in a plasma enhanced chemical vapor deposition device, vacuumizing, introducing argon-hydrogen mixed gas with the flow rate of 40-80 sccm, heating to 300-500 ℃, starting a radio