KR-20260062278-A - Contact material composite for having ARC erosion resistance and manufacturing method of the same

Abstract

The present invention relates to a contact material composition having arc erosion resistance and a method for manufacturing the same. A method for manufacturing a contact material composition having arc erosion resistance for an electric vehicle DC relay comprises: a powder pretreatment step for forming a mixed powder by mixing tungsten powder and a space holder material; a press molding step for forming a green compact by applying pressure to the mixed powder; a sintering heat treatment step for forming a porous tungsten structure by heat treating the green compact; and an impregnation heat treatment step for forming a tungsten-copper composition by impregnating copper particles into the porous tungsten structure. The powder pretreatment step is characterized by mixing tungsten carbide balls and tungsten powder in a weight ratio of 1:1 to 2:1 and performing the process within a range of 4 to 12 hours at a rotational speed of 300 rpm to 400 rpm.

Inventors

• 박창수
• 박광석
• 서보성
• 강장원
• 나태욱
• 하태준

Assignees

• 한국생산기술연구원

Dates

Publication Date

20260507

Application Date

20241029

Claims (7)

1. A method for manufacturing a contact material composition having arc erosion resistance for electrical contacts of an electric vehicle DC relay, A powder pretreatment step for forming a mixed powder by mixing tungsten powder and a space holder material; A press molding step for forming a green compact by applying pressure to the above-mentioned mixed powder; A sintering heat treatment step for heat-treating the above green compact to form a porous tungsten structure; and It includes an impregnation heat treatment step for forming a tungsten-copper composition by impregnating copper particles into the porous tungsten structure, and The above powder pretreatment step A method for manufacturing a contact material composition having arc erosion resistance, characterized by mixing tungsten carbide balls and tungsten powder in a weight ratio of 1:1 to 2:1 and performing the process at a rotational speed of 300 rpm to 400 rpm for a range of 4 hours to 12 hours.
2. In paragraph 1, The above sintering heat treatment step A hydrogen reduction process is performed in a 100% hydrogen atmosphere at a temperature of 750°C to 850°C within a temperature range of 1 hour to 2 hours, and A method for manufacturing a contact material composition having arc erosion resistance, characterized by sintering at a temperature of 1,300°C to 1,900°C in a vacuum atmosphere of 10⁻⁴ to 10⁻⁵ torr.
3. In paragraph 2, Before the above sintering heat treatment step A method for manufacturing a contact material composition having arc erosion resistance, characterized by further including a step of removing the space holder material to form a porous green compact by immersing the green compact in a solvent.
4. In Paragraph 3, A method for manufacturing a contact material composition having arc erosion resistance, characterized in that the above space holder material includes paraffin or NaCl.
5. In Paragraph 3, The above impregnation heat treatment step A method for manufacturing a contact material composition having arc erosion resistance, characterized by being performed in a hydrogen reducing atmosphere at a temperature of 1,100℃ to 1,400℃ and a time range of 10 minutes to 120 minutes.
6. In Paragraph 3, After the above impregnation heat treatment step A step of processing a copper-impregnated tungsten composition into a contact material for an electric vehicle DC relay; A step of polishing the surface of the above contact material; A step of cleaning the surface-polished contact material; and A method for manufacturing a contact material composition having arc erosion resistance, characterized by including the step of annealing the cleaned contact material in a hydrogen atmosphere at a temperature range of 850°C to 950°C.
7. A contact material composition having arc erosion resistance manufactured by any one of the methods selected from claims 1 to 6.

Description

Contact material composite for having ARC erosion resistance and manufacturing method of the same The present invention relates to a contact material composition having arc erosion resistance and a method for manufacturing the same. In particular, it relates to a contact material composition having arc erosion resistance and a method for manufacturing the same, which can be utilized as a contact material for a DC circuit breaker of an electric vehicle to improve the arc erosion resistance of the electrical contact even when using a high-capacity and high-voltage battery, and to improve the physical properties of the W-Cu composition. A DC relay is a type of switch that supplies and cuts off battery current to other components, and it is used in many electrically operated products such as electric vehicles, energy storage devices, factory automation robots, ships, and submarines. Recently, as the performance of electric vehicles continues to improve and high-capacity, high-voltage batteries are increasingly adopted, the importance of corresponding technologies for controlling DC loads is growing. While DC relays are being upgraded to high performance to handle the high-voltage batteries of electric vehicles, their electrical contacts are subjected to extreme mechanical and thermal stress during operation. For example, since the temperature at which an arc occurs during operation can rise to thousands of degrees, there is a technical challenge in addressing the degradation of copper contact materials. Extensive research is being conducted on electrical contact materials using copper-tungsten alloys to address the degradation of copper contacts. Copper-tungsten alloys are widely used as contact tips and contact electrodes due to their excellent resistance to arc corrosion, mechanical wear, contact welding, and electrical conductivity. Copper-tungsten alloys are typically manufactured using powder metallurgy methods such as liquid phase sintering or impregnation. Liquid phase sintering is a method in which tungsten powder and copper powder are mixed, molded, and then sintered at a temperature above the melting point of copper. Depending on the powder processing steps used to increase sintering density, it is classified into ball milling, mechanical alloying, and active sintering using trace elements (Co, Ni). In liquid phase sintering, molten liquid copper penetrates into the pores of a porous tungsten body through capillary forces, thereby enabling the production of high-density composite materials. However, this method presents difficulties in manufacturing porous tungsten preforms consisting solely of continuous, open pores. When manufacturing copper matrix composite materials with a high tungsten content using the impregnation method, the low solubility of copper and tungsten can result in many pores. When applying powder metallurgy methods such as liquid phase sintering or impregnation, the tungsten particles cannot be raised to the melting temperature (3410°C), so the tungsten particles are slightly melted, which can result in more pores within the composite material. An example of a technology for manufacturing a copper-tungsten alloy is disclosed in the following patent documents 1 and 2. For example, Patent Document 1 below discloses a method for impregnating a sintered body with an impregnation material, wherein a sintered body is prepared and at least a portion of the surface of the sintered body is coated with a copper plating layer. By heating a carbon-based container, a carbide layer is formed on the surface of the sintered body excluding the portion where the copper plating layer is formed, to which the molten impregnation material is repelled, and copper of the required weight for impregnation is melted and impregnated into the sintered body. Furthermore, Patent Document 2 below discloses a copper-impregnated molybdenum and/or tungsten-based powder metal alloy for excellent thermal conductivity. A sintered material for use in internal combustion engines, such as valve seat inserts, comprises a pressed base powder metal mixture and a Cu-rich phase impregnated in the pores of the base powder metal mixture. The base powder metal mixture comprises at least one of Mo and W, and at least one additive such as B, N, and/or C. The amount of Mo and/or W is 50 wt% to 85 wt% based on the total weight of the material. At least one additive is present in a total amount of 0.2 to 25 wt% based on the total weight of the material, and the Cu-rich phase is present in an amount of 15 wt% to 50 wt% based on the total weight of the material. This material also has a thermal conductivity of at least 70 W/mK. FIG. 1 is a drawing exemplarily showing a DC relay to which a tungsten-copper composition is applied according to an embodiment of the present invention. Figures 2a and 2b are diagrams illustrating the arc erosion generation mechanism in the DC relay of Figure 1. FIG. 3 is a drawing for explaining a method for ma