Black tungsten wire is a filament made of tungsten metal. Usually, the surface is not polished or specially treated, and the graphite emulsion is attached, showing a dark gray or black appearance, hence the name "black tungsten wire". Tungsten is a high melting point (about 3422°C), high density, corrosion-resistant metal, and is widely used in many fields due to its excellent physical and chemical properties. Black tungsten wire is mainly made by powder metallurgy and wire drawing. Its surface may retain trace oxides due to oxidation or production process, so the color is darker.
The main uses of black tungsten wire include the following aspects. First, it is often used in the lighting industry as the filament of traditional incandescent lamps and halogen lamps. Due to the high melting point and good thermal stability of tungsten, black tungsten wire can work for a long time at high temperature without melting or deformation. Secondly, black tungsten wire is used as cathode emission material in the electronics industry, such as in vacuum tubes and picture tubes, relying on its high electron emission performance to achieve stable operation. In addition, black tungsten wire is also used to manufacture heating elements, such as the core components of industrial furnaces and electric heaters, because it can withstand extreme high temperature environments.
During the production process, black tungsten wire is usually pressed into a rod from tungsten powder, and then sintered at high temperature and drawn multiple times to form a filament. Although the demand for black tungsten wire in the lighting field has declined with the rise of new lighting technologies such as LEDs, it still has an irreplaceable role in high-temperature industries, medical equipment (such as X-ray tubes) and scientific research.
The advantages of black tungsten wire include high temperature resistance, corrosion resistance and high mechanical strength, but it is difficult to process, has high cost, and its brittleness needs to be considered in some applications. With the advancement of materials science, doped tungsten wire (such as potassium, aluminum, etc.) has gradually replaced some black tungsten wire applications to improve performance. In short, as a classic high-performance material, black tungsten wire still plays an important role in modern industry.
