Tungsten filament lamp: In addition to a small amount of tungsten wire used as high temperature furnace heating material, the heat pipe and composite materials, such as reinforcement, the vast majority of tungsten filaments are used to produce a variety of incandescent and halogen tungsten filament and the electrode of the gas discharge lamp. In order to reduce the work of its electron emission, the tungsten filament or tungsten rod used as a cathode of a gas discharge lamp, must be added 0.5 to 3% of thorium, which is called tungsten thorium wire. Because thorium is a radioactive element that pollutes the environment, cerium is used instead of thorium to form tungsten cerium or tungsten cerium rods. However, the cerium evaporation rate is high, so the tungsten cerium wire or tungsten cerium rods can only be used for small power gas discharge lamp.

Once the tungsten wire is recrystallized after high temperature use, it becomes brittle and easily broken under shock or vibration. In some of high requirements and high reliability of the electro-optical source products, in order to prevent the rupture of the filament, it often add  3 to 5% of rhenium into doped tungsten wire, known as tungsten rhenium wire, it can make the brittle transition temperature of tungsten down to room temperature or below room temperature. This is a very strange effect of rhenium, it has not yet found an element to replace rhenium, to produce the same effect in tungsten.

Tungsten has a good acid and alkali resistance at room temperature, but it is easy to be oxidized in the humid air, so the fine tungsten wire can not be stored in a humid environment for a long time. In addition, at 1200 degrees, tungsten began to react with the carbon to produce carbonization, so the burning hydrogen treatment of tungsten should pay attention to this problem, otherwise graphite lubricant will react with the surface of tungsten filament to make the wire become brittle fracture.