CN-117488129-B - Preparation method of silver plate with low air content

Abstract

The invention particularly relates to a preparation method of a silver plate with low air content, which comprises the following steps of S1, adding silver powder into a crucible to smelt into silver liquid, S2, adding massive silver graphite solid into the silver liquid, dispersing the massive silver graphite solid into silver graphite powder at high temperature, reducing smelting temperature and heating, and S3, casting the silver liquid into a mould, and cooling to obtain the silver plate. The method comprises the steps of taking massive silver graphite leftovers as deoxidizers, removing oxygen in molten silver liquid, firstly, crushing massive silver graphite into silver graphite powder when the massive silver graphite is placed on the surface of the high Wen Yinye, covering the surface of the molten silver liquid, enabling the silver graphite powder to be in full contact with the silver liquid, continuously consuming oxygen in the silver liquid, secondly, not introducing impurity ions, keeping purity of silver plates, and thirdly, enabling gas in air to hardly penetrate through a silver graphite powder layer to enter the molten silver liquid because the graphite powder is micron-sized or even nano-sized powder, and further playing a role of isolating air.

Inventors

• ZHOU KEWU
• DAI LINTAO
• LIU YINGFEI
• MIAO RENLIANG
• WANG BAOFENG
• LIN YINGTAO

Assignees

• 温州伟达贵金属粉体材料有限公司

Dates

Publication Date

20260508

Application Date

20231117

Claims (9)

1. 1. The preparation method of the silver plate with low air content is characterized by comprising the following steps of: s1, adding silver powder into a crucible to smelt into silver liquid; s2, adding massive silver graphite solids into the silver liquid, dispersing the massive silver graphite solids into silver graphite powder at a high temperature, reducing the smelting temperature and heating; and S3, casting the silver liquid into a die, and cooling to obtain the silver plate.
2. 2. The method of claim 1, wherein the silver powder has a water content of less than 2%.
3. 3. The method for preparing a silver plate with low air content according to claim 1, wherein silver powder is continuously added to cover the surface of the silver liquid in the smelting process in the step S1.
4. 4. The method of claim 1, wherein in step S2, the bulk silver graphite solid is dispersed as silver graphite powder at 1100-1200deg.C.
5. 5. The method of claim 1, wherein in step S2, the bulk silver graphite solid comprises one or more of silver graphite extruded filament corner pieces, silver graphite extruded cake corner pieces, and silver graphite contact corner pieces.
6. 6. The method of manufacturing a low air content silver plate according to claim 1, wherein in step S2, the melting temperature is lowered to 1000-1050 ℃ and heated for 10-15 minutes.
7. 7. The method of claim 1, wherein in step S2, the heated silver solution is heated and plant ash is covered on the silver solution.
8. 8. The method of manufacturing a low air content silver plate according to claim 7, wherein the heated silver solution is heated to 1100-1150 ℃ and heated for 1-2min.
9. 9. The method of claim 1, wherein in step S3, a layer of graphite is sprayed on the contact area of the die and the silver liquid by burning acetylene before casting.

Description

Preparation method of silver plate with low air content Technical Field The invention belongs to the field of contact materials of low-voltage distribution equipment, and particularly relates to a preparation method of a silver plate with low air content. Background Silver graphite material is widely applied to various circuit breakers for protecting power lines and motors. Silver graphite materials have good fusion welding resistance and conductivity, and low and stable contact resistance. And the silver graphite extruded yarn, the silver graphite extruded cake and the silver graphite contact product are scrapped and the like. The silver plate with low air content can be processed into silver-based composite material, and also can be processed into silver foil strips with low resistivity and no bubble defect in appearance, so that the silver foil strips have wide application in the production process of contact materials. The patent CN103658566 discloses a method for producing silver ingots with low oxygen content, which mainly comprises the steps of adding charcoal or graphite particles into the bottom of a crucible, adding silver powder for smelting, and covering combustible matters on the surface of the silver liquid, so that external oxygen is prevented from entering the silver liquid, and oxygen in the silver liquid can be consumed. And finally casting the molten silver liquid into a mould to prepare the silver ingot with low oxygen content. However, in actual production, it is found that combustibles such as newspaper or coke powder or straw or flour are carbonized into blocks during combustion, resulting in insufficient contact surface between the combustibles and molten silver, and the molten silver is required to be continuously added with combustibles during oxygen removal, but the added combustibles are not actually contacted with the molten silver but are covered on the previously carbonized combustibles, thereby resulting in poor actual deoxidizing effect of the method and being unfavorable for generalized production. There is a need for a new and efficient low air content silver plate manufacturing process. Disclosure of Invention The invention aims to overcome the defects and shortcomings in the prior art, and provides a preparation method of a silver plate with low air content, which comprises the following steps: s1, adding silver powder into a crucible to smelt into silver liquid; s2, adding massive silver graphite solids into the silver liquid, dispersing the massive silver graphite solids into silver graphite powder at a high temperature, reducing the smelting temperature and heating; and S3, casting the silver liquid into a die, and cooling to obtain the silver plate. Preferably, in step S1, the silver powder has a water content of less than 2%. Through this setting, because moisture content is too high, vapor can wash out silver powder in the high temperature in-process, and the air gets into silver liquid through the hole that leaves, and this setting can further improve the degasification effect. Preferably, in step S1, silver powder is continuously added to cover the surface of the silver liquid in the smelting process. Through this setting, stop the air to get into the silver liquid that the below melted through the silver powder that constantly adds, further promote the degasification effect. Preferably, in step S2, the bulk silver graphite solid is dispersed as silver graphite powder at 1100-1200 ℃. Through the arrangement, as the silver graphite is a powder metallurgy pressed sintering product, after silver is melted at 1100-1200 ℃, the silver loss in the silver graphite can cause the forming force between silver powder and graphite powder to be weakened, the massive silver graphite is crushed into silver graphite powder, the silver graphite powder is covered on the surface of molten silver liquid, and the silver graphite powder is fully contacted with the silver liquid, so that oxygen in the silver liquid is continuously consumed. Preferably, in step S2, the bulk silver graphite solid includes one or more of silver graphite extruded filament corner pieces, silver graphite extruded cake corner pieces, and silver graphite contact corner pieces. Preferably, in step S2, the smelting temperature is reduced to 1000-1050 ℃ and heated for 10-15 minutes. Preferably, in step S2, the heated silver solution is warmed up and plant ash is covered on the silver solution. Through this setting, cover plant ash can block silver graphite powder or graphite powder, prevent silver graphite powder or graphite powder to get into the silver plate when the casting, plant ash can block in the air gets into silver melt simultaneously, further reduces the gas content of making the silver plate. During actual operation, residual silver graphite powder can be gathered on one side far away from the casting nozzle through the graphite rod, plant ash is covered on silver liquid on one side close to the castin