Tungsten copper composite material for vacuum switchgearTungsten copper materials have been widely used in vacuum switch appliances as electrical contacts of high-voltage electrical switches, occupying a large share in tungsten copper products. And because of the excellent electrical conductivity and electrical ablation resistance of tungsten copper materials, it has been used in new high-voltage electrical switches that use Van as the extinguishing medium.
At the same time, around the twentieth century, another newly developed tungsten copper material for vacuum switches was widely used in medium and high voltage electrical appliances with a large amount and a wide range.This type of vacuum electrical switch has a small volume, good performance and convenient operation. And it is easy to maintain, has a long service life, and has the characteristics of being able to adapt to flammable, explosive, alpine, humid and corrosive environments. In addition to the properties required for conventional electrical contacts, the tungsten-copper contact material for vacuum also requires that it meet the requirements for extremely low gas content in vacuum application materials, so special processes such as high temperature or vacuum degassing, vacuum Infiltration and other preparation.
Among the vacuum tungsten copper contact materials, in addition to the conventional tungsten copper contact material grades, high-tungsten and low-copper tungsten copper products have been developed, such as, etc., several major vacuum tungsten copper material grades, their gas content, and electrical conductivity The properties and hardness are shown in Table 1. When the tungsten copper material is required to be used in the occasion of low cut-off value, a small amount of other low-melting metals can be added thereto, such as.
Tungsten copper composite material for electrodeIn the longer period of the development of EDM, copper and copper alloys were widely used as processing electrodes. Although copper and copper alloys are inexpensive and easy to use, copper and copper alloy electrodes are not resistant to electrical spark ablation, resulting in large electrode consumption and poor processing accuracy, sometimes requiring multiple processing.
With the increasing accuracy of molds and the use of many difficult-to-machine materials and components, as well as the maturity of EDM technology, the use of tungsten copper materials as electrodes for EDM is increasing. Electro-machined electrodes using tungsten copper materials not only improve the accuracy of the molds and parts being processed, but also have small electrode losses and high processing efficiency, and can even complete the rough and finish processing of the product in one go.
EDM electrodes are characterized by a large variety of specifications, small batches and large totals. The tungsten-copper material used as the electrode for electroprocessing should have the highest possible density and uniformity of the structure, especially for some slender rods, tubes, and special-shaped electrodes. The utilization rate is very low.
Tungsten copper composite material for electronic packaging and heat sinkTungsten-copper two-phase composites have low thermal expansion coefficient and high electrical and thermal conductivity, and are considered as a good heat sink material in high-power and large-scale integrated circuits. In recent years, many experts and scholars at home and abroad have conducted a lot of research on tungsten copper as a heat sink material. These studies mainly include powder modification, adding active agents to improve the sintering density of tungsten copper.
Tungsten-copper composite material has both high heat resistance and good thermal conductivity, and at the same time has a coefficient of thermal expansion that matches the silicon wafer, arsenic, and ceramic materials, so it is obtained as an insert, a connector and a heat sink. With rapid application, it has become a new important electronic packaging and heat sink material.
At present, the relative density of tungsten-copper materials can be as high as above. Using powder materials with higher purity, the thermal conductivity of the materials can reach '. As electronic packaging and heat sink materials, there are higher requirements for the quality and performance of tungsten copper materials, not only high purity and uniform organization, low air leakage rate, good thermal conductivity, and small thermal expansion coefficient, so strict production control Process and product quality. Table 1 lists the performance of the main tungsten copper materials used for packaging heat sinks.
Tungsten copper alloy for high temperatureDue to the high melting point of tungsten, the tungsten copper material has strong high temperature resistance.In the 19th century, the United States began to use it as a rail material for electromagnetic guns, nozzle throat liners on rocket missiles, and gas rudder components. . Its high temperature resistance principle is that when the temperature of the gas is close to or even higher than the melting point of metallic tungsten, the tungsten copper material absorbs a large amount of heat due to the evaporation of the copper contained in it, which causes the temperature of the surface area of the tungsten copper machining component to be greatly reduced. Withstand the high temperature atmosphere.
The development and application of high-temperature tungsten copper materials in the field of military defense and aerospace are also increasing significantly. As aerospace technology and military defense materials, tungsten copper materials must have high reliability, which puts forward higher requirements for material properties, especially high temperature strength and ablation performance in high temperature gas.