|
The contact elements are key components in the electrical switches, the switch electrical performance as well as life largely depends on the contact material is good or bad. With the increasing levels of manufacturing of electrical switches, increasing varieties, especially due to the saving of silver and other precious metals, protect the needs of its natural resources depleted, section silver electrical contact materials research by people attach great importance to. Ideal electrical contact material must meet a wide range of physical properties, mechanical properties, electrical contact properties, chemical properties, manufacturing performance requirements, these requirements are diverse, and some performance requirements are contradictory to each other, and thus a single material can be made with these requirements is almost impossible. To this end, usually using the powder metallurgy method, the different properties from each other but can not dissolve or small solubility of two or more metal or alloy combination, made of composite material, to achieve the above main performance requirements, and obtained the best overall performance. This article in accordance with the requirements of the electrical contact performance, copper-based body to add a variety of components using powder metallurgy technology, developed a new type of high-performance copper-based composite silver electrical contacts. The material has a higher conductivity, the better the oxidation resistance and welding resistance, low contact resistance and good mechanical properties, to meet the low and medium pressure electrical requirements of the electrical contacts, can replace currently widely The use of silver-based electrical contact materials, but can also improve the electrical performance of the switch, which greatly reduces the cost of electrical contact elements. Requirements of the electrical contact material has good resistance to electric ablation and anti-welding properties, but the pure copper is difficult to achieve the kinds of requirements, which need to choose a low-melting component, below the melting temperature of the copper, this group yuan substances easily than copper oxidation, burning or evaporation, and the formation of oxides easy to decompose, the decomposition will be easy to extinguish the arc arc energy consumption, excess oxygen is expelled, forming holes or microporous This porous structure conducive to contact welding resistance. This article Sn, Cd, Zn, Bi, Sb of the low-melting component, electrical properties and the oxidation test was conducted on the material, the results show that the best performance of the conductivity of the low-melting component of an electrical contact material for Cd, but Cd steam toxicity. Bi conductivity and contact resistance manifested better overall performance. Comprehensive consideration of the influence of Bi on each performance, and determine that the Bi is added in an amount of 2%. In order to improve the mechanical properties of the copper substrate, to increase its hardness and improve the wear resistance and welding resistance the group element needs to contain a high melting point, high hardness, good electrical properties and mechanical properties with a copper matrix composite. Select WC, TiC, B 4 C as the melting point, high hardness element, by adding these elements to the sample conductivity and stiffness seen, B 4 C particles exhibit the best performance. B 4 C different content material properties that copper matrix composites B 4 C can increase the hardness and wear resistance of the material, but added in an amount exceeding 3%, the hardness of the specimen a downward trend, abrasion With
|