Silver tungsten carbide graphite contact material and preparation method thereof

Abstract

The invention discloses a novel silver tungsten carbide graphite contact material and a preparation method thereof, which belong to the technical field of electric engineering material. The preparation method comprises the following steps of: putting tungsten carbide powder, graphite powder and tungsten into a reaction vessel; adding deionized water and 40% hydrazine hydrate into the reaction vessel; spraying 50-500 g / l silver ammonia complex solution into the reaction vessel at a flow rate of 5 to 500 ml / min with stirring at a rotating speed of 50 to 200 r / min to coat silver powder on the tungsten carbide graphite, the graphite powder and the tungsten particles; and performing high-energy ball milling, destressing, initial-pressing forming, sintering, re-pressing forming, annealing and re-pressing forming to obtain the contact material, wherein the weight percents of silver, tungsten carbide and graphite in the contact material are 72 to 85 percent, 13 to 24 percent and 2 to 5 percent respectively, and the weight of tungsten is 0.5 to 1.5 percent of the total weight of the silver, the tungsten carbide and the graphite. By using a coating process with a chemical plating principle, the invention improves the physical bonding strength between non-wetting materials, improves chemical properties and physical properties of the materials, greatly optimizes the conductivity and improves the arc erosion resistance.

Description

technical field [0001] The invention relates to a novel silver tungsten carbide graphite contact material and a preparation method thereof, belonging to the technical field of electrical materials. Background technique [0002] Among the electrical contact materials of low-voltage electrical appliances, silver tungsten carbide graphite contact materials are widely used in various molded case circuit breakers, frame-type universal circuit breakers, and automotive electrical appliances. This is because the material has good welding resistance and electrical conductivity, low and stable contact resistance. The role of tungsten carbide and graphite is to prevent the bonding and welding of contacts, and do not form any insulation to increase the contact resistance, but tungsten carbide and graphite have a stable arc slope and poor thermal stability in air. Poor arc corrosion resistance is the biggest defect of this material. In China, the mechanical powder mixing process is gen...

AI Technical Summary

Problems solved by technology

The role of tungsten carbide and graphite is to prevent the bonding and welding of contacts, and do not form any insulation to increase the contact resistance, but tungsten carbide and graphite have a stable arc slope and poor thermal stability in air. Poor arc corrosion resistance is the biggest defect of this material

In China, the mechanical powder mixing process is generally used for production. This process is simple and easy, with few processes, low equipment requirements, high material utilization rate, and low production cost. However, the obtained contacts are uneven in structure and poor in density. High arc erosion rate