Method for preparing copper-based electrical contact material based on foaming infiltration process and product thereof

Abstract

The invention discloses a method for preparing a skeleton used in the infiltration preparation process of copper-based electrical contact materials. A foaming agent is added to Cu-based mixed powder for sintering strengthening, and the sintering-strengthened Cu-based powder is wrapped with a separator and sintered to a liquid state. Then crush and sieve the above phase to obtain high-strength porous Cu-based powder, press the porous Cu-based powder into a skeleton, spray the silicon-containing corundum powder on the working surface of the skeleton, and then place the pure copper sheet on the top of the skeleton. Liquid phase infiltration is performed on the framework to obtain a Cu-based electrical contact material with high copper content and low resistivity. The invention solves the problem that the Cu-based electrical contact material with high copper content can only be produced by the solid phase sintering process, and has higher density and resistance to burnout compared with the Cu-based electrical contact material with the same copper content prepared by the sintering process It has lower resistivity and surface oxidation resistance, and the use performance such as electrical life has been greatly improved.

Description

technical field [0001] The invention relates to the field of electrical contact materials, in particular to a method for preparing a copper-based electrical contact material based on a foaming infiltration process and a product thereof. Background technique [0002] Copper-based contact materials are widely used as contacts in low-voltage circuit breakers, frame circuit breakers, DC relays, etc., and are generally made by infiltration method. The content of refractory phases (W, WC, Mo) is between 40wt% and 80wt%. %between. In the occasions with high temperature rise requirements, such as the contact resistance of materials with refractory phase content higher than 40wt% in DC relays, it is difficult to meet the requirements for use, and contacts with high copper content can only be used solid-phase sintering. , unable to meet the requirements of switch short-circuit capability and electrical life performance, which seriously restricts the development of the industry. [0...

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Problems solved by technology

In this way, the manufactured product contains part of the infiltrated structure, and the main structure is still a solid-phase sintered structure, and it is difficult to ensure a uniform structure.

At the same time, due to the high ductility and toughness of silver and the high strength of WC (W), the crushing process of AgWC (W) infiltrated and dense materials is very difficult, and it is even more difficult to crush into powders with ideal particle sizes. This process is difficult to achieve. mass production

[0010] The Chinese invention patent with the publication number CN104209520A adds polyacrylate pore-forming agent to the powder to increase the pores. The strength of the powder produced by this method is low when making Cu(W, WC, Mo)40 and Cu content is lower. Copper-based materials can meet the production requirements. When making Cu-based materials with a copper content higher than 40%, the skeleton will collapse or even burst due to the severe deformation of the pores during the infiltration process.

[0011] 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 produced by this method also has the problem of low internal strength of the powder. During the infiltration process of Cu (W, WC, Mo), the powder will collapse or even explode due to the severe deformation of the pores and cannot be formed. The mechanism is basically similar to that of polyacrylate pore formers.

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