Preparation method of silver tungsten carbide contact material

Abstract

The invention discloses a preparation method of a silver tungsten carbide contact material. The preparation method comprises a step of obtaining a pressed blank, and is characterized in that the stepof obtaining the pressed blank comprises the following procedures: soaking tungsten carbide powder with a silver nitrate solution, drying an obtained mixed material, carrying out thermal decompositionreaction, crushing, reducing, and pressing obtained silver tungsten carbide mixed powder to obtain the pressed blank, wherein the silver nitrate solution is a silver nitrate aqueous solution. The method is simple in process, short in production period and low in forming difficulty, and the obtained contact is more uniform in metallographic structure, higher in density and hardness and lower in resistivity.

Description

Technical field[0001]The invention relates to a preparation method of a contact material, in particular to a preparation method of a silver tungsten carbide contact material.Background technique[0002]In the contact industry, the common silver tungsten carbide contacts with low tungsten carbide content (20-30%) are usually produced by the process of pressing-sintering-repressing to obtain a contact with higher density and meeting electrical requirements. The high tungsten carbide content (50-80%) of silver tungsten carbide contacts, due to the increase in tungsten carbide content, the difficulty of press molding has doubled, and it is impossible to obtain high-density silver tungsten carbide contacts. The performance will drop linearly and it is difficult to meet the requirements of electrical appliances. Therefore, silver tungsten carbide contacts with high tungsten carbide content usually need to be processed by infiltration process to obtain high density and superior performance c...

AI Technical Summary

Problems solved by technology

[0008] Although the method of pre-adding silver by chemical coating or electroplating can help to improve the forming strength when preparing the tungsten carbide skeleton and finally obtain a silver tungsten carbide contact material with high density and high tungsten carbide content through infiltration treatment, But they all have following deficiencies: 1) after the silver tungsten carbide coated mixed slurry is made by chemical reaction, it needs to be cleaned with pure water, and a large amount of waste water is produced in this process, and there are problems of sewage treatment and environmental pollution; 2 ) needs to consume a large amount of chemical reagents (such as sodium hydroxide, polyethylene glycol or hydrazine hydrate, etc.) in the preparation process, which not only has an impact on the health of production operators, but also has environmental pollution problems; In the coating reaction (need to be carried out in a liquid system), due to the high density of tungsten carbide, the sinking speed in the reaction solution is high, so there will be serious clustering and aggregation, and it is difficult to obtain a truly uniform composite powder

However, due to the increase of the ball milling process, on the one hand, the production cycle of the product is prolonged and the energy consumption is increased; on the other hand, the impurities brought in during the ball milling process still have an adverse effect on the performance of the obtained contact.

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