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.

Tungsten copper FGM thermal shock resistance is also called as thermal stability, thermal shock stability or resistance to temperature abruptness. It is an important indicator for evaluating the resistance of damage when it endures rapid temperature change. The closer the test values are, the higher the precision is.The main influencing factors of tungsten copper FGM thermal shock resistance include CTE (Coefficient of Thermal Expansion), thermal conductivity, elastic modulus, material inherent strength, fracture toughness. Generally, the smaller CTE, the less the volume change caused by the temperature change, the less the corresponding temperature stress, the better the thermal shock resistance; the higher the inherent strength of the material, the greater the strength to withstand thermal stress without damage, thermal shock resistance is better; the larger the elastic modulus, the smaller the elasticity, the smaller the elastic deformation of the material can not alleviate and release thermal stress, which is not good for thermal shock resistance.

Straight brick water quenching method in China (YB376). (200 to 230 mm) X (100 to 150 m) K (50 to 100 mm) was inserted into a furnace preheated to 1100 ° C for 50 minutes and then quenched in water at room temperature for 3 minutes and then dried. The thermal shock resistance was characterized by the number of thermal cycles in which the end face was broken by half;
Long strip test method in China (YB4018). The sample (230mm x 114mm x 31mm or 230 mm x 65mm x  31mm) to a surface as the heating surface, in the hot plate from the room temperature to a prescribed rate heated to 1000 ℃, for 30min, and then quenched in the air. The degree of damage was evaluated by the percent change of flexural strength before and after thermal shock. The bending strength retention ratio of each brick is calculated by the following formula: Rr = Ra / Rb × 100%, Rr - Retention strength (%), Ra-bending strength (MPa) Fracture strength of specimens before thermal shock.
In addition, there is United States panel test method (ASTMC38), long sample test method (ASTMCll00) and the European Refractory Manufacturers' Association's Cylindrical Sample Water Quenching (PRE / RS-1).