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What is Non-sag tungsten?

Non-sag tungsten also called doped tungsten is a dispersion-strengthened microalloy with elemental potassium, which is contained as microscopic bubbles in the tungsten lattice. Under working conditions in an incandescent lamp the potassium is a gas under high pressure. These gas bubbles essentially prevent the recrystallization of the tungsten wire and are responsible for the outstanding creep resistance of NS tungsten at the extremely high temperatures of a glowing lamp filament. More than 90% of NS tungsten is used for incandescent lamps.

In addition, small amounts are used as defroster heating wires in automobile windshields and as heating wire coils for aluminium evaporation in metallization applications. The presented papers deal with the chemical reactions and the chemical compounds occurring along the path from tungsten raw materials to the final NS tungsten filament; a compendium of present knowledge on the different chemical aspects of NS tungsten manufacture is presented. It is composed of nine individual papers, each of them written by experts working in the field.

What is Non-sag tungsten wire?

The invention relates to non-sag tungsten wire for being used in light sources or heating elements, which tungsten wire is prepared from a tungsten block by powder metallurgy process with thermomechanical technique, and has an overlapped crystal structure after recrystallization and contains a dopant material. The essential feature of the tungsten wire according to the invention is that as the dopant material, it contains at least one of the following additive materials.

Method of manufacturing a non-sag tungsten wire for electric lamps

To essentially eliminate aluminum and silicon as contaminants in a doped tungsten wire, the tungsten wire is obtained by mechanical working of reduced tungsten blue oxide which contains as a primary or major constituent a special hexagonal ammonium tungsten bronze of the general formula (NH4)X (NH3)y WO3. A liquid doping step is carried out by adding a solution containing potassium nitrate, the special doped ammonium tungsten bronze forming preferably more than 70% by weight of the overall tungsten blue oxide. The special hexagonal ammonium tungsten bronze is made by decomposing ammonium paratungstate in an ammonium atmosphere, preferably at a temperature between about 400° and 550° C.

Application of non-sag tungsten wire

Non sag tungsten wire can be used in the car and motorbike light for its non-sag property. The wire used in the car and the same series light shouls have the property of anti-shaking, so that the car light could have the stable light source to direct the drivers at night. the non-sag tugnsten light can meet the requirements of the property, which is used to decrease the shaking degree. That is to say, non-sag tungsten wire is a much better choice in the lights of car and motorbike, etc.