Sheet Silver Nickel Tungsten Electrical Contact

Silver nickel electrical contact has been widely used in various low-voltage electrical appliances because of its good thermal conductivity, low and stable contact resistance, excellent processing performance and other advantages. However, due to its poor anti fusion welding performance, the application range of silver nickel electrical contact is affected.

In order to solve the existing technical problems, some scholars have proposed a preparation process of sheet silver nickel tungsten electrical contact material with simple process and uniform additive distribution in the base material, which is characterized by the following steps:

1)calculate the amount of tungsten trioxide powder, nickel powder and silver nitrate required according to the material ratio of the silver nickel tungsten electrical contact to be prepared, and calculate the amount of sodium hydroxide required for the reaction of silver nitrate and sodium hydroxide to generate silver oxide according to the amount of silver nitrate, weigh it for standby; take silver nitrate and dissolve it with water to prepare 20-40w / W% silver nitrate solution, and then mix the tungsten trioxide powder and silver nitrate solution. The suspension containing silver nitrate and tungsten trioxide was obtained by stirring in the reactor;

2)Prepare 10-30w / W% sodium hydroxide solution by dissolving sodium hydroxide with water, add it to the suspension obtained in step 1) stir reaction, precipitate, generate, filter, and obtain composite powder of silver oxide and tungsten trioxide;

3)The composite powder of silver oxide and tungsten trioxide is washed to neutral, dried, crushed, roasted, and then crushed to obtain the composite powder of silver oxide and tungsten trioxide;

4)The silver nickel tungsten oxide composite powder was mixed with nickel powder to obtain the silver nickel tungsten oxide composite powder;

5)The silver nickel tungsten oxide powder was formed by oil pressure, and then reduced in reducing atmosphere to obtain silver nickel tungsten billet;

6)The sheet Ag Ni W electrical contact material is obtained by re pressing and re burning the obtained Ag Ni W blank.

The composite powder of silver oxide and tungsten trioxide is obtained by the reaction of sodium hydroxide with silver nitrate suspension containing tungsten trioxide powder. Because the density of tungsten trioxide powder (7.16g / cm³) is close to that of silver oxide (7.143g / cm³), the mixture of tungsten trioxide powder and silver oxide can be more uniform, and the tungsten trioxide powder can be more evenly distributed in the silver oxide matrix. On the other hand, the obtained silver nickel tungsten oxide billets further refine the tungsten particles in the process of being reduced to silver nickel tungsten billets, so that the distribution of tungsten elements in the matrix is more uniform and dispersive, so that the obtained silver nickel tungsten electrical contact materials have uniform metallographic structure, thus having excellent electrical properties and simple process. It has little pollution to human body and environment and is suitable for industrial production.

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