Method for preparing AgNi electric contact material based on foaming infiltration process and product of method

Abstract

The invention discloses a method for preparing an AgNi electric contact material based on a foaming infiltration process and a product of the method. The method comprises the following steps of: adding a foaming agent into AgNi mixed powder to sinter and strengthen the AgNi mixed powder; wrapping the sintered and strengthened AgNi powder with a separant, and sintering the powder to be above a liquid phase; crushing and screening to obtain high-strength porous AgNi powder; preparing the porous AgNi powder into a special columnar porous framework spindle through isostatic pressing; placing a pure silver sheet above the framework; putting the framework into a graphite crucible; carrying out infiltration on the framework spindle at a high temperature to obtain an AgNi / Ag composite spindle with high silver content and low resistivity; extruding the spindle into a thin strip; and finally punching the thin strip into the AgNi electric contact material. With the method of the invention adopted, the problem of the combined extrusion of a thin strip, and the problem that a low-nickel high-silver AgNi electric contact material can be manufactured only by adopting a solid-phase sintering process are solved at the same time. Compared with the material manufactured by the solid-phase sintering process, the material manufactured by the method of the invention has the advantages of higher compactness, high burning loss resistance, and greatly improved service performance such as long electric service life.

Description

technical field [0001] The invention relates to the field of electrical contact materials, in particular to a method for preparing an AgNi electrical contact material and a product thereof, which is prepared by a brand-new foaming infiltration process. Background technique [0002] AgNi electrical contact materials are widely used in circuit breakers, miniature circuit breakers, leakage protection switches, contactors, and relays. Generally, the pressing sintering method or extrusion method is used, and the Ni content is between 10wt% and 35wt%. In switch design, the requirements for switch temperature rise are getting higher and higher, especially in small micro circuit breakers, the contact resistance of materials with Ni content higher than 35wt% is difficult to meet the use requirements, while the electrical contact materials with low Ni content can only use solid The phase sintering method cannot meet the requirements of short-circuit resistance and anti-burning loss of...

AI Technical Summary

Problems solved by technology

[0011] The Chinese invention patent with the publication number CN104209520A adds a polyacrylate pore-forming agent to the powder to increase the pores. The powder produced by this method has low strength and can meet the production requirements when making AgNi30 and AgNi materials with higher Ni content. When making AgNi materials with a Ni content below 30%, the skeleton will collapse or even burst due to the severe deformation of the pores during the infiltration process.

Similarly, using this method to make high-silver AgNi materials will also have the problem that the skeleton collapses or even bursts during infiltration and cannot be formed.

[0012] The Chinese invention patent with the publication number CN112548099A provides a method for making porous alloy powder by using ammonium bicarbonate foaming agent. The powder made by this method also has the problem that the internal strength of the powder is too low. During the AgNi infiltration process, the powder will cause the skeleton to collapse or even explode due to the severe deformation of the pores, and the mechanism is basically similar to that of the polyacrylate pore-forming agent.

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