A kind of silver-molybdenum electrical contact material with high dispersion degree and preparation method thereof

Abstract

The invention discloses a silver-molybdenum electrical contact material with high dispersibility and a preparation method thereof. The additive can be effectively dispersed by coating the molybdenum powder in the early stage and the ball milling pretreatment of the additive, so that the additive can grow uniformly on the surface of the molybdenum powder, and the maximum Play the role of additives to the greatest extent, effectively improve the wetting angle of the melt to the skeleton, and make the wetting performance better. At the same time, the high-energy crushing treatment of the coating powder can effectively remove the internal pores in the preparation process of the coating powder, increase the bulk density of the powder, and make the pore size distribution in the initial compaction as the infiltration channel uniform, interconnected, and melt It can infiltrate evenly to achieve complete densification and eliminate defects. After the infiltration of the skeleton, there is no hole, no aggregation, and no exposed reinforcing phase particles on the cross-section, and the silver and molybdenum form a good combination, which improves the dispersion and compactness of the silver-molybdenum material.

Description

technical field [0001] The invention belongs to the technical field of electrical contact materials, in particular to a high dispersion silver molybdenum electrical contact material and a preparation method thereof. Background technique [0002] With the higher and higher requirements for the reliability of electrical appliances at the power distribution end, electrical appliance manufacturers are constantly launching low-voltage power distribution products with higher indicators. The improvement of the breaking index of electrical appliances means that the thermal penetration of the arc is extremely strong when breaking. At this time, the contact material is easily eroded by the arc, causing the electrical appliance to fail to connect and malfunction. Taking into account the properties of materials such as electrical conductivity, burn resistance, and corrosion resistance, at this stage, the material composition is not adjusted, and the dispersion of the material itself, th...

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Problems solved by technology

[0005] When the content of molybdenum in the silver-molybdenum powder is too high and the molybdenum particles are too small, and the molybdenum mass percentage increases to 50%-65%, the dispersibility, processability and infiltration difficulty of the molybdenum particles are greatly improved. Conventional mixed powders The additives cannot be uniformly dispersed, resulting in the infiltration of internal defects and pores that cannot be solved; in the conventional mixed powder, it is inevitable to encounter a large number of molybdenum particles adjacent to the particles during the powder mixing and molding process; and due to its ultra-high Hardness, when the molybdenum particles are in contact with the surface of the particles, plastic deformation will hardly occur, so the particles cannot form mutual meshing, resulting in cracks in the compact, and even the compact cannot be formed; even if the metallographic structure of the formed product is molybdenum Aggregation, silver accumulation, many internal pores and defects, and the product's anti-burning and anti-welding properties become poor

[0006] The conventional powder mixing process or the conventional coating process cannot avoid the agglomeration of molybdenum particles and additive particles, and cannot remove the internal pores in the preparation process of the coating powder. Therefore, the reinforcement phase aggregation phenomenon cannot be completely eliminated when the silver-molybdenum contact material is prepared by the conventional powder mixing process; The coating process cannot avoid pores and product delamination after infiltration, as well as cross-section holes, aggregation, and exposed reinforcement phase particles, and silver and molybdenum cannot form a good combination

Therefore, the production of highly dispersible silver-molybdenum materials has always been a difficult problem in the industry, and this problem also limits the further improvement of the electrical breaking performance to a considerable extent.

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