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Old 01-10-2018, 11:01 AM   #1 
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Silver Tungste Cobalt-Chromium Alloy

Silver Tungsten alloy to tungsten based on the addition of other elements of the alloy. Among the metals, tungsten has the highest melting point, high temperature strength and creep resistance, and good thermal conductivity, electrical conductivity and electron emission properties. It is widely used in tungsten and its alloys in addition to a large amount of tungsten and its alloys In the electronics and electric light industry, but also in the aerospace, casting, weapons and other departments for the production of rocket lances, die-casting mold, armor piercing, contacts, heating body and heat shield. Tungsten was first used to make incandescent filaments. In 1909, W.D.Coolidge made the tungsten wire by tungsten powder pressing, remelting, swaging and drawing process. From then on, the production of tungsten wire got rapid development. In 1913, I. Langmuir and Rogers discovered that the use of tungsten-thorium wire after the tungsten-thorium wire (also known as thorium wire) emitted electrons performed better than pure tungsten wire, is still widely used to date. In 1922, a tungsten filament with excellent anti-sagging performance (called doping or non-sagging tungsten filament) was developed, which is a great progress in tungsten filament research. Non-sagging tungsten filament is a widely used superior filament and cathode material. In the 1950s and 1960s, extensive research was conducted on tungsten-based alloys, hoping to develop tungsten alloys that can work from 1930 to 2760 for the manufacture of high-temperature-resistant components used in the aerospace industry. Among them, tungsten-rhenium alloys are more studied.

Tungsten melting and processing forming technology has also been studied, using consumable arc and electron beam melting of tungsten ingots obtained by extrusion and plastic processing into some products; but the melting ingot coarse grain, poor plasticity , Processing difficulties, the rate of finished products is low, so smelting - plastic processing technology failed to become the main means of production. In addition to chemical vapor deposition (CVD) and plasma spray can produce very few products, powder metallurgy is still the main means of manufacturing tungsten products. China was able to produce tungsten wire in the 1950s. Research on the smelting, powder metallurgy and processing of tungsten in the 1960s allowed the production of sheets, sheets, foils, rods, tubes, wires and other shaped parts. Silver tungsten alloy hot electron emission ability is low. In addition to the conventional macro performance requirements, but also requires porosity, microstructure and performance, it is necessary to take a special process, to be vacuum degassing, vacuum infiltration and other complex processes.

Tungsten copper electronic packaging and heat sink material, both with low expansion characteristics of tungsten, but also has high thermal conductivity of copper, its thermal expansion coefficient and thermal conductivity can be adjusted by changing the composition of tungsten copper, which provides a more tungsten Wide range of applications. Due to the high heat resistance and good thermal conductivity of the tungsten copper material, but also with the thermal expansion coefficient matching silicon, gallium arsenide and ceramic materials, it has been widely used in semiconductor materials. For high power devices and packaging materials, heat sink materials, cooling components, ceramics and gallium arsenide base and so on. A small amount of a certain element may have a great impact on the nature of the alloy. For example, impurities in a ferromagnetic alloy can change the properties of the alloy. Unlike pure metals, most alloys do not have a fixed melting point and the mixture is in a solid-liquid co-existing state when the temperature is in the melting temperature range. Aluminum castings have feeder refueling, al-si class alloy solidification temperature range, riser feeding high efficiency, easy access to dense tissue castings. Other types of cast aluminum alloy solidification temperature range, riser feeding low efficiency, poor casting density. Aluminum is extremely easy to get in and oxidize, so the pouring system must ensure that the molten aluminum flows in faster and more smoothly to avoid agitation. A variety of casting methods are suitable for Cobalt-Chromium Alloy castings. When the production is less, available sand casting, sand should be used to shape; mass production of important castings, the use of special casting.


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