Method for preparing silver metal oxide electrical contact material through internal oxidation method to improve welding-resistant performance

Abstract

The invention discloses a method for preparing a silver metal oxide electrical contact material through an internal oxidation method to improve welding-resistant performance. According to the technical scheme, excess nickel elements are added in the smelting process, and can be fully alloyed with a silver substrate in the melting process, along with decreasing of the cast ingot temperature, the nickel elements are oversaturated to be separated out in a silver alloy, and separated-out nickel particles are evenly distributed in the silver substrate. In the subsequent internal oxidation process,the silver alloy can be fully oxidized, only the surfaces of the nickel particles in the silver substrate are oxidized, the interiors of the nickel particles in the silver substrate cannot be oxidized, the binding strength between oxidation aggregation layers on the surfaces of the nickel particles and the silver substrate is low, and thus the tensile strength of the material is lowered. In the electrical contact process, due to the existence of the nickel particles evenly distributed in silver metal oxide, the welding force of a welding bridge can be effectively decreased, the welding position between contacts is easier to disconnect, and thus the welding-resistant performance of the silver metal oxide material is improved.

Description

technical field [0001] The invention relates to the field of electrical contact materials, in particular to a method for preparing a silver metal oxide electrical contact material by an internal oxidation method for improving anti-welding performance. Background technique [0002] In the field of electrical contacts, silver metal oxide materials occupy an important position in the entire electrical contact material system due to their excellent comprehensive electrical properties. The metal oxides and additives in the silver matrix belong to the strengthening phase for the silver matrix, and the arc erosion resistance and welding resistance of the silver matrix are improved by means of dispersion strengthening. In the process of electrical contact, welding of contacts is a common form of failure. Therefore, how to improve the anti-welding performance of electrical contact materials is an important direction in the field of electrical contact materials research. [0003] Fus...

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Problems solved by technology

[0006] Patent ZL201410309080.9 discloses a preparation method of silver metal oxide electrical contact materials containing nickel fibers, which uses silver-nickel alloy or nickel fibers on the surface of silver metal oxide ingots, and extrudes the composite ingots into wires. After the wire is cut, the ingot is pressed again, and the composite wire is extruded for the second time. The purpose is to improve the conductivity of the silver metal oxide material, and at the same time achieve the purpose of saving silver. Due to the existence of nickel fibers, it can reduce the contact resistance and increase the melting temperature. Pond viscosity, but after extrusion, the nickel fiber and the silver matrix have a good bonding strength, which does not improve the anti-welding performance of the material

[0007] Patent ZL201310601506.3 discloses a silver metal oxide tungsten composite electrical contact material, which uses tungsten element with high melting point in the silver metal oxide to improve the welding resistance of the material, but this method is only suitable for pre-oxidation process Or the material of powder metallurgy process, the material of internal oxidation process cannot improve the anti-welding performance of the material through this method

[0008] Patent 201210297893.1 and patent ZL201310700969.5 disclose a method to improve the welding resistance of materials, but they are only suitable for pre-oxidation process, not suitable for the improvement of welding resistance of materials in internal oxidation process

[0009] However, the method of improving the welding resistance of silver metal oxide materials in the conventional internal oxidation process is to increase the oxide content, or add metal additives that can form alloys with silver, and require the metal oxides of the additives to wet the silver matrix. If the angle is larger, the anti-welding performance of the material will be improved, but this will lead to a decrease in the electrical conductivity of the electrical contact material and an increase in the arc energy.

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