Tungsten copper contact for high-voltage breaker is kind of oil-free switchgear that uses SF6 gas as arc quenching medium and insulating medium. It has better performance in arc extinguish and insulation than oil circuit breaker and has high requirement of application, management, operation of SF6. So it main used for the voltage level of 110kv. There are two main structure of tungsten copper contact for high-voltage breaker:

Porcelain column structure: It also known as blocks, a plurality of identical unit interrupters and pillar insulators can be used to form the circuit breakers of different voltage levels. The circuit breaker consists of three independent single-phase and one hydraulic, electrical control cabinet. Each phase consists of two pillars of porcelain sets of four interrupters (fracture) in series. In each pillar porcelain top of the unit is equipped with two unit interrupter, 120 ° angle V-shaped arrangement, the two parallel capacitors are arranged horizontally.
Tank structure: Using the advantages of box-type multi-oil circuit breaker, the circuit breaker and the transformer together, compact structure, anti-seismic and anti-fouling ability. It is generally three-phase split-type, single-phase from the base, insulated porcelain casing, current transformers and single-break interrupter with the shell composition. Each phase is equipped with a hydraulic mechanism and a control cabinet which can be operated individually and can be operated in three phases by means of electrical control.

In addition, it has so many advantages compared with other materials:
1. As insulating gas, SF6 has many advantages, is colorless, tasteless, non-toxic, non-flammable inert gas and has performance in cooling arc. Especially cooling effect under high arc temperature;
2. The chemical effect of SF6 gas itself is very stable, and has a very high dielectric strength;
3. Blocking effect: give full play to the effect of air blowing arc, interrupter small size, simple structure, breaking current, arc time is short, breaking capacitor or inductor current without re-ignition, over-voltage;
4. Long electrical life: 50kA full capacity of continuous breaking up to 19 times, the cumulative breaking current up to 4200kA, maintenance cycle is long, suitable for frequent operation;
5. Good sealing performance: SF6 gas has lower water content, arc chamber, resistance and pillar into separate air separation, on-site installation without opening, after installation with automatic connection; installation easy maintenance, and to prevent dirt and moisture Into the circuit breaker inside.

Tungsten copper contact for high-voltage breaker is also called as high-voltage switch, which not only plays an important role in cutting or closing high-voltage circuit in the no-load current and load current, but also in protecting relay when short circuit. 

Tungsten copper contact for electronic has excellent wear and corrosion resistance and mainly used for controlling electron motion in vacuum, air or solid. So it has a wide range of application, such as electronic components, connectors, semiconductor discrete devices, electro-acoustic devices, laser devices, electronic display devices, optoelectronic devices, sensors, power supplies, switches and other electronic chemical materials and parts.

Tungsten copper contact for vacuum switch is an important component in automatic control system and directly affects the operation of power system. Due to perfect performance of tungsten copper material, it can be widely used in metallurgical, chemical, oil, steel, machinery, refrigeration equipment, water pump pressure control, low water level protection and other industrial equipments.

Tungsten copper lightning rod used to protect buildings, tall trees and other devices to avoid lightning. It connects the grounded drain network with compliant conductor by lightning stripper at the top of the protected object. Basically, it can be divided into several types:
1. Direct tungsten copper lightening rod: For petrochemical storage, radio and television, gas stations, construction buildings, beacon, communications base stations, weather stations, military bases, radar room, the bank building;
2. Special tungsten copper lightening rod: It is applicable to higher building microwave communication station, radar base station, beacon station, communication base station, military base, radar room, bank building, astronomical weather station and other important places;
3. Pre-discharge tungsten copper lightning rod: When the lightning rod to receive lightning, flashing through the lightning wave processing device, using the shell and the center ground rod has a gap of 3mm, constitute a coupling capacitor. At the same time the housing is grounded through an inductor coil (center ground rod). When the down-lead is close to the flashover, the inductance is open due to the extremely high frequency.

Between the independent lightning rod and the object to be protected should be not less than 5m distance, so as to avoid lightning strike. Independent of the lightning rod should be set up an independent grounding device, and the ground between the network distances of not less than 3m; 35kV and below the high-voltage power distribution unit structure and the roof should not be installed lightning rod. Installed in the framework of the lightning rod should be connected with the grounding network, and installation of centralized grounding device; lightning rod and grounding device from the road and exit distance should be larger than 3m, or should be paved gravel or asphalt surface 5 ~ 8cm thickness, to prevent the person from step-by-step voltage hazards; transformer door-type structure should not be installed on the lightning rod.

Tungsten copper infiltration is to manufacture tungsten skeleton with density and strength, then filled in copper liquid under capillary force. And it can be divided into infiltrated Cu after high-temperature sintering skeleton and mix powder infiltration after low-temperature sintering. The process of high-temperature W skeleton sintering:Tungsten powder + 0.1%~1.5% binder → Mix  → Pressing (400℃~800℃, low vacuum）→ Binder removal (1000℃, 1~2h) → Pre-sintering (1800℃~2000℃, H2, 1h) → High-temperature sintering (1300℃~1400℃, H2 or vacuum) → Infiltration.

This method can be made relative density> 99.2% of tungsten and copper materials. As a result of high temperature sintering, W reduction is sufficient, low melting point impurities and difficult to restore the low-cost oxides can be removed by volatilization and thermal decomposition. Tungsten copper material with low oxygen content, high purity, high temperature sintering method suitable for the manufacture of copper mass fraction φ (Cu) is not greater than 15% of the tungsten copper material. High-temperature sintering method using the material made of high relative density, good overall performance. But its production circle is long and complex, it difficult to be popularized.

Partial mixed powder sintering copper infiltration method: Tungsten powder + 2%~6% copper powder + 0.5%~2.5% binder (such as nickel powder) → Mix  → Pressing (1300℃~1400℃, H2 or vacuum）→ Sintering (1200℃~1350℃, H2 or vacuum) → Infiltration. The method has the advantages of simple technological process and is suitable for producing tungsten and copper composite material with φ (Cu)> 20%. This method produces tungsten copper material, copper distribution along the tungsten grain boundaries, tungsten skeleton strength than high-temperature sintering method, such as this method as the contact material in the circuit breaker, easy to produce ablation.

By experiment, we can find that with the increasing AlN, W-Cu composite density tends to decrease. Theoretical density reduction is due to the low density of AlN itself (3.26g / cm3), which is much less than that of tungsten and copper. So with the increase of AlN content, the theoretical density of the whole material decreases naturally. While the measured density decrease is not only because of the low density of AlN itself, it also includes from relative density: one is the addition of nano AlN particles hinders the rearrangement of tungsten particles, which the tungsten copper material densification in liquid sintering depends on. The higher the content of nano-AlN particles, the more obvious the blocking effect, the more difficult the rearrangement of tungsten particles, the more difficult to fill the pores; the other is the wetting ratio of AlN particle is not as good as W and Cu at high temperature, so the addition will decrease the density of tungsten copper composite materials. In a word, few nano AlN particles have no effect on W-Cu composite material and it can further improve physical and mechanical properties.

W-Cu composite material usually uses Brinell hardness (HB) or Rockwell hardness (HR). In accordance with the addition of AlN and hardness measurements plotting the change curve, we can clearly found that the hardness of W-Cu composite material is improved with the increasing amount of nano AlN particles, which also indicates the addition of AlN particles reduced the interfacial bonding, but it played the role of fine grain strengthening and dispersion strengthening, especially for matrix copper. However, when the content exceeds 1%, the increasing trend of hardness is slowed down, because the density of tungsten-copper composite decreases, which leads to the increase of porosity in matrix.

Tungsten copper lightening gap electrode is composed of two electrodes, which one of the electrodes is fixed on the insulator, connected with the charged wire, and the other electrode is connected with the grounding device through the auxiliary gap, and the gap between the two electrodes is kept at a specified gap. 

Tungsten copper inlaid electrode usually is used for Cu, Al, Ag and other non-ferrous metals spot welding. But W and Mo do not have good radiating performance actually, we usually use tungsten copper as contact. 

Tungsten copper electrode isostatic pressing include CIP, sintering, infiltration, HIP and it can remarkably improve the properties of tungsten copper electrode. Copper content of more than 20% of the tungsten copper alloy due to higher copper content, the use of pre-mixed sintering infiltration process: the porous skeleton is obtained, and the copper content is further infiltrated to obtain the required copper content, and the tungsten-copper blank after infiltration is subjected to hot isostatic pressing treatment.

CIP (Cold Isostatic Pressing) has many advantages, such as:
1. It can manufacture large-size electrodes. Large size electrode molding needs large compressor and the blank is difficult to keep uniform. While this process can be suitable for various rods, tubes, plates under 200mm or other high-performance tungsten copper electrode with square, rectangular, triangular;
2. CIP has uniform force of each direction, so the density and strength of compact is higher than other processes;
3. It uses soft mold for processing, so it is beneficial for manufacturing irregular shape.

HIP (Hot Isostatic Pressing) can remove pores, defects and improve crystalline structure. Through the hot isostatic pressing of high temperature and high pressure, on the one hand tungsten copper billet in the loose, shrinkage and infiltration defects by the deformation of a closed a diffusion to be eliminated, on the other hand, to improve the internal organizational structure, so that in the processing state, To further improve performance, thereby obtaining high-density, high-performance processing of tungsten copper electrode material.