Tungsten Wire
It wasn't until the early 1900s that
tungsten was recognized as the superior choice for lighting filaments. Initially, the brittleness and lack of malleability prohibited its utilization. This problem, though, was eventually solved when it was realized that through process involving hydrogen and extremely high temperatures, fused tungsten can be rolled and drawn into wires, without the danger of breakage. This process involves the following actions and vocabulary: pressing, presintering, full sintering, swaging and drawing. Pressing is an initial step in the process concerning
tungsten powder, which needs to be loading and pressed into a hollow container in order for it to become compacted into a united shape. Presintering involves positioning the compacted tungsten powder into a furnace with high temperatures and a hydrogen atmosphere, so that it may be further secured. Full sintering involves a water-cooling component and electric current, in which the tungsten is passed through. This is yet another process by which the tungsten is further secured and strengthened. Swaging and drawing are both processes in which the desired shape of the wire is achieved.
Tungsten wire has an extremely high melting point, good corrosion resistance and great strength at high temperatures. Because of these qualities, tungsten wire is often used for bulb filaments, along with other high-temperature applications. By using the appropriate temperatures, it was understood that its degree of compliance improved; tungsten metal is, when left in its pure state, brittle; rolling the metal into a wire form, however, increases its strength and allows for easier handling of the metal, ultimately causing the metal to reach its full density. By mixing the tungsten powder with other organic or metallic materials, the final microstructure of tungsten wire consists of fiber-like structures, providing the wire with bend ductility. Essentially, in order for the tungsten to become its desired wire form, some type of additional agent must be incorporated. While the percentage of tungsten used in the manufacturing of such products is rather small, the value tungsten wires have acquired to such industries is undeniable. For this reason, the process described above is important to appreciate.
